Data Logging IoT Weight Scale

by Brent Rubell and lady ada

published April 02, 2019, last edited April 09, 2025

posted in Hacks CircuitPython Internet of Things - IOT

Save Download

Intermediate

Project guide

Overview

How many grams of coffee did I add to my pour-over?

Is the bag of cat food empty?

Did I remember to water the plant?

What's the weight of these screws in my workshop?

To answer these questions (and more), you're going to build an internet-enabled scale to track weight data over a period of time.

To do this, you'll be performing a bit of hardware hacking - tearing down a DYMO Postage scale and soldering wires to connect it to a PyPortal. Then, you'll add some CircuitPython code to the PyPortal which allows you to read the the scale remotely using Adafruit IO - our easy-to-use internet of things service.

This scale is not just for keeping track of your coffee - you can can monitor anything! Here are some examples:

Place a bag of cat food on the scale and enable Adafruit IO Feed Email Notifications for when you run out of cat food.
Science experiments - no need to watch and chart a scale's weight - let Adafruit IO do that for you with automatic graph visualizations!
Are you a beekeeper? Track the weight of a honeycomb and have Adafruit IO notify you when it exceeds a certain weight.

This is an introduction to hacking and controlling consumer off-the-shelf electronics with CircuitPython. To perform this guide, you'll need some soldering experience and willingness to tear down a consumer product your purchased.

Adafruit IO

Adafruit IO is the easiest way to stream, log, and interact with your data. It's built from the ground up to be easy to use - we do the hard stuff so you can focus on the fun stuff.

Data such as temperature and light levels can be hard to visualize and quantify - Adafruit IO makes it simple. Send IO your data and it can store and display it using charts, graphs, gauges, and more!

CircuitPython Code

CircuitPython is great for building Internet-of-Things projects. Using the Adafruit IO CircuitPython module, you can easily send data to Adafruit IO, receive data from Adafruit IO, and easily manipulate data with the powerful Adafruit IO API.

We've also built a DymoScale module for CircuitPython to make interfacing with these scales incredibly easy.

You can rapidly update your code without having to compile and store WiFi and API secret keys on the device. This means that there's no editing code and re-uploading whenever you move the PyPortal to another network - just update a file and you're set.

Parts

WARNING: Follow the steps in this guide at your own risk! DYMO Scales are not designed to be taken apart and soldered to. Following this guide WILL void your warranty.

To use this guide, you'll need a DYMO scale. We've tested this guide with DYMO M25 and a DYMO M10.

Note: There are differences between the two scale models we tested (the CircuitPython_DymoScale library handles this for you, you can use either). If you choose to use another DYMO mode with this guide, be warned that we have not tested other DYMO scales with this library and your scale may not work with our library.

Adafruit PyPortal - CircuitPython Powered Internet Display

PyPortal, our easy-to-use IoT device that allows you to create all the things for the “Internet of Things” in minutes. Make custom touch screen interface...

guides with product

$54.95

In Stock

Add to Cart

Materials

You'll need the following materials to complete this guide. If you do not have them handy, consider picking them up from Adafruit:

1 x Soldering Station

Digital Genuine Hakko FX-888D

Add to Cart

1 x Solder Spool

Solder Wire - 60/40 Rosin Core

Add to Cart

1 x Wire Strippers

Hakko Professional Quality 20-30 AWG Wire Strippers - CSP-30-1

Add to Cart

1 x Spudger

Spudger - Double Sided Prying Tool

Add to Cart

1 x Screwdriver

Adafruit Pocket Screwdriver

Add to Cart

1 x USB Cable

USB cable - USB A to Micro-B - 3 foot long

Add to Cart

Page last edited March 08, 2024

Text editor powered by tinymce.

Install CircuitPython

CircuitPython is a derivative of MicroPython designed to simplify experimentation and education on low-cost microcontrollers. It makes it easier than ever to get prototyping by requiring no upfront desktop software downloads. Simply copy and edit files on the CIRCUITPY "flash" drive to iterate.

The following instructions will show you how to install CircuitPython. If you've already installed CircuitPython but are looking to update it or reinstall it, the same steps work for that as well!

Set up CircuitPython Quick Start!

Follow this quick step-by-step for super-fast Python power :)

Download the latest version of CircuitPython for the PyPortal via CircuitPython.org

Download the latest version of CircuitPython for the PyPortal Pynt via CircuitPython.org

Click the link above to download the latest version of CircuitPython for the PyPortal.

Download and save it to your desktop (or wherever is handy).

Plug your PyPortal into your computer using a known-good USB cable.

A lot of people end up using charge-only USB cables and it is very frustrating! So make sure you have a USB cable you know is good for data sync.

Double-click the Reset button on the top in the middle (magenta arrow) on your board, and you will see the NeoPixel RGB LED (green arrow) turn green. If it turns red, check the USB cable, try another USB port, etc. Note: The little red LED next to the USB connector will pulse red. That's ok!

If double-clicking doesn't work the first time, try again. Sometimes it can take a few tries to get the rhythm right!

You will see a new disk drive appear called PORTALBOOT.

Drag the adafruit-circuitpython-pyportal-<whatever>.uf2 file to PORTALBOOT.

The LED will flash. Then, the PORTALBOOT drive will disappear and a new disk drive called CIRCUITPY will appear.

If you haven't added any code to your board, the only file that will be present is boot_out.txt. This is absolutely normal! It's time for you to add your code.py and get started!

That's it, you're done! :)

PyPortal Default Files

Click below to download a zip of the files that shipped on the PyPortal or PyPortal Pynt.

PyPortal Default Files

PyPortal Pynt Default Files

Page last edited March 08, 2024

Text editor powered by tinymce.

Assembly

WARNING: Disassemble the Dymo Scale at your own risk! Remember the Dymo Scale is not designed to be opened by users and will require some force to open. Take the proper safety precautions to protect your eyes and body from harm when using tools to open the scale. The instructions below are a suggestion and they might not work with current or future Dymo Scales.

Take your scale out of the box - it's hardware hackin' time!

We're going to begin by popping the front faceplate off.

Run a spudger along the top edge of the scale's faceplate, from right to left. You should feel the faceplate pop as you run it along.

Once the spudger reaches the end of the faceplate, it should pop off.

Then, remove the front faceplate from the scale.

Flip the scale over - at the end of the scale are removable rubber feet, pop these out with a flathead screwdriver or a spudger.

We used the Adafruit Pocket Screwdriver - the precision screwdriver set we usually use don't have a long enough shaft to reach the screw.

Unscrew both screws from the bottom of the scale.

After the screws are removed, the top cover should remove cleanly without any extra force.

Using a spudger, gently pry at the seam between the scale's top cover and the base.

As you go along the edges of the scale, the plastic will pop. Do not force the spudger in any direction other than sideways - you'll risk breaking the scale's thin plastic cover.

Continue running the spudger along the scale's seams until you've gone completely around the scale. When you get to the front of the scale (near the LCD), you'll be running the spudger towards the bottom of the scale's base.

Do not completely remove the cover - there are wires still connected to the front panel!

Slowly remove the cover, tilting it slowly towards the front of the scale.

Do not completely remove the cover - there are wires connected to the front panel

With the cover slightly open, you may notice some wires snagging. With your spudger or a dull screwdriver, move these wires away from the plastic posts so they do not snap when you open the case fully.

Remove the foam adhesive on the right and left sides of the scale. This will let the PCB move around more, giving you more wiggle-room to solder later.

Flip over the PCB and preheat your soldering iron for the next few steps.

Wiring

We're going to be soldering to the trace highlighted.

Locate this trace on the PCB - it should be directly above the T28 silkscreen text.

We can not solder to the board until we've removed the solder mask.

Using a flathead screwdriver, scrape off the green solder-mask until you've revealed the copper underneath.

Be careful to scrape up-and-down, instead of left-to-right, so you don't accidentally cut the trace.

With a pair of wire cutters, remove the header plug from the end of the white wire.

Then, using a pair of wire strippers, strip a short (~2mm) length of wire from the end of the white wire.

Tin the copper pad you exposed with the razor by applying a small amount of solder to it. Then, tack the wire to the pad by heating the wire with the soldering iron.

The connection between the white wire and this pad is still fragile. Using kapton tape, or a dab of hot glue, secure the white wire to the back of the board.

Solder the red header pin to the USB V+ pin on the left side of the board.

Then, solder the black header pin to the USB VSS pin.

Check out the right side of the board. There's two red wires below a white box on the PCB attached to the KG/LB button.

Note: On the DYMO M-25 model, this button is labeled G/OZ instead of KG/LB.

Using wire cutters, remove the header pins from a 3-Pin JST-PH cable.

Then, with a pair of wire strippers, strip off a small amount of the rubber sheathing covering each pin.

Solder the white wire from the JST cable to the KG/LB (or G/OZ) pad on the PCB.

Solder the black wire from the JST cable to the GND pad on the PCB.

Re-Assembly and PyPortal Wiring

Before you re-assemble the PyPortal, make sure the connections for the kg/oz button and data pins are still connected.

The rectangular holes in the scale's faceplate are perfect for wires to be threaded through them.

Thread the cables through the rectangular holes in the faceplate.

Then, place the top of the scale onto the metal top plate and re-attach the screws underneath the scale to secure the top of the scale.

On the right side of the PyPortal are two 3-Pin JST-PH connectors. These connectors can be used for analog or digital communication.

Connect the 3-Pin JST-PH connector from the button to D3 on the PyPortal.

Connect the other 3-Pin JST-PH connector for the scale data to D4 on the PyPortal.

We're done! Lets move onto the software to control and communicate with the DYMO scale.

Page last edited March 08, 2024

Text editor powered by tinymce.

Create Your settings.toml File

CircuitPython works with WiFi-capable boards to enable you to make projects that have network connectivity. This means working with various passwords and API keys. As of CircuitPython 8, there is support for a settings.toml file. This is a file that is stored on your CIRCUITPY drive, that contains all of your secret network information, such as your SSID, SSID password and any API keys for IoT services. It is designed to separate your sensitive information from your code.py file so you are able to share your code without sharing your credentials.

CircuitPython previously used a secrets.py file for this purpose. The settings.toml file is quite similar.

Your settings.toml file should be stored in the main directory of your CIRCUITPY drive. It should not be in a folder.

CircuitPython settings.toml File

This section will provide a couple of examples of what your settings.toml file should look like, specifically for CircuitPython WiFi projects in general.

The most minimal settings.toml file must contain your WiFi SSID and password, as that is the minimum required to connect to WiFi. Copy this example, paste it into your settings.toml, and update:

your_wifi_ssid
your_wifi_password

Download File

Copy Code

CIRCUITPY_WIFI_SSID = "your_wifi_ssid"
CIRCUITPY_WIFI_PASSWORD = "your_wifi_password"

CIRCUITPY_WIFI_SSID = "your_wifi_ssid"
CIRCUITPY_WIFI_PASSWORD = "your_wifi_password"

Many CircuitPython network-connected projects on the Adafruit Learn System involve using Adafruit IO. For these projects, you must also include your Adafruit IO username and key. Copy the following example, paste it into your settings.toml file, and update:

your_wifi_ssid
your_wifi_password
your_aio_username
your_aio_key

Download File

Copy Code

CIRCUITPY_WIFI_SSID = "your_wifi_ssid"
CIRCUITPY_WIFI_PASSWORD = "your_wifi_password"
ADAFRUIT_AIO_USERNAME = "your_aio_username"
ADAFRUIT_AIO_KEY = "your_aio_key"

CIRCUITPY_WIFI_SSID = "your_wifi_ssid"
CIRCUITPY_WIFI_PASSWORD = "your_wifi_password"
ADAFRUIT_AIO_USERNAME = "your_aio_username"
ADAFRUIT_AIO_KEY = "your_aio_key"

Some projects use different variable names for the entries in the settings.toml file. For example, a project might use ADAFRUIT_AIO_ID in the place of ADAFRUIT_AIO_USERNAME. If you run into connectivity issues, one of the first things to check is that the names in the settings.toml file match the names in the code.

Not every project uses the same variable name for each entry in the settings.toml file! Always verify it matches the code.

settings.toml File Tips

Here is an example settings.toml file.

Download File

Copy Code

# Comments are supported
CIRCUITPY_WIFI_SSID = "guest wifi"
CIRCUITPY_WIFI_PASSWORD = "guessable"
CIRCUITPY_WEB_API_PORT = 80
CIRCUITPY_WEB_API_PASSWORD = "passw0rd"
test_variable = "this is a test"
thumbs_up = "\U0001f44d"

# Comments are supported
CIRCUITPY_WIFI_SSID = "guest wifi"
CIRCUITPY_WIFI_PASSWORD = "guessable"
CIRCUITPY_WEB_API_PORT = 80
CIRCUITPY_WEB_API_PASSWORD = "passw0rd"
test_variable = "this is a test"
thumbs_up = "\U0001f44d"

In a settings.toml file, it's important to keep these factors in mind:

Strings are wrapped in double quotes; ex: "your-string-here"
Integers are not quoted and may be written in decimal with optional sign (+1, -1, 1000) or hexadecimal (0xabcd).
- Floats, octal (0o567) and binary (0b11011) are not supported.
Use \u escapes for weird characters, \x and \ooo escapes are not available in .toml files
- Example: \U0001f44d for 👍 (thumbs up emoji) and \u20ac for € (EUR sign)
Unicode emoji, and non-ASCII characters, stand for themselves as long as you're careful to save in "UTF-8 without BOM" format

When your settings.toml file is ready, you can save it in your text editor with the .toml extension.

Accessing Your settings.toml Information in code.py

In your code.py file, you'll need to import the os library to access the settings.toml file. Your settings are accessed with the os.getenv() function. You'll pass your settings entry to the function to import it into the code.py file.

Download File

Copy Code

import os

print(os.getenv("test_variable"))

import os

print(os.getenv("test_variable"))

In the upcoming CircuitPython WiFi examples, you'll see how the settings.toml file is used for connecting to your SSID and accessing your API keys.

Page last edited March 08, 2024

Text editor powered by tinymce.

Internet Connect!

Connect to WiFi

OK, now that you have your settings.toml file set up - you can connect to the Internet.

To do this, you need to first install a few libraries, into the lib folder on your CIRCUITPY drive. Then you need to update code.py with the example script.

Thankfully, we can do this in one go. In the example below, click the Download Project Bundle button below to download the necessary libraries and the code.py file in a zip file. Extract the contents of the zip file, open the directory examples/ and then click on the directory that matches the version of CircuitPython you're using and copy the contents of that directory to your CIRCUITPY drive.

Your CIRCUITPY drive should now look similar to the following image:

Update to CircuitPython 9.2.x or later to use this example.

Download Project Bundle

Copy Code

# SPDX-FileCopyrightText: 2019 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

from os import getenv

import adafruit_connection_manager
import adafruit_requests
import board
import busio
from digitalio import DigitalInOut

from adafruit_esp32spi import adafruit_esp32spi

# Get wifi details and more from a settings.toml file
# tokens used by this Demo: CIRCUITPY_WIFI_SSID, CIRCUITPY_WIFI_PASSWORD
ssid = getenv("CIRCUITPY_WIFI_SSID")
password = getenv("CIRCUITPY_WIFI_PASSWORD")

print("ESP32 SPI webclient test")

TEXT_URL = "http://wifitest.adafruit.com/testwifi/index.html"
JSON_URL = "http://wifitest.adafruit.com/testwifi/sample.json"


# If you are using a board with pre-defined ESP32 Pins:
esp32_cs = DigitalInOut(board.ESP_CS)
esp32_ready = DigitalInOut(board.ESP_BUSY)
esp32_reset = DigitalInOut(board.ESP_RESET)

# If you have an AirLift Shield:
# esp32_cs = DigitalInOut(board.D10)
# esp32_ready = DigitalInOut(board.D7)
# esp32_reset = DigitalInOut(board.D5)

# If you have an AirLift Featherwing or ItsyBitsy Airlift:
# esp32_cs = DigitalInOut(board.D13)
# esp32_ready = DigitalInOut(board.D11)
# esp32_reset = DigitalInOut(board.D12)

# If you have an externally connected ESP32:
# NOTE: You may need to change the pins to reflect your wiring
# esp32_cs = DigitalInOut(board.D9)
# esp32_ready = DigitalInOut(board.D10)
# esp32_reset = DigitalInOut(board.D5)

# Secondary (SCK1) SPI used to connect to WiFi board on Arduino Nano Connect RP2040
if "SCK1" in dir(board):
    spi = busio.SPI(board.SCK1, board.MOSI1, board.MISO1)
else:
    spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
esp = adafruit_esp32spi.ESP_SPIcontrol(spi, esp32_cs, esp32_ready, esp32_reset)

pool = adafruit_connection_manager.get_radio_socketpool(esp)
ssl_context = adafruit_connection_manager.get_radio_ssl_context(esp)
requests = adafruit_requests.Session(pool, ssl_context)

if esp.status == adafruit_esp32spi.WL_IDLE_STATUS:
    print("ESP32 found and in idle mode")
print("Firmware vers.", esp.firmware_version)
print("MAC addr:", ":".join("%02X" % byte for byte in esp.MAC_address))

for ap in esp.scan_networks():
    print("\t%-23s RSSI: %d" % (ap.ssid, ap.rssi))

print("Connecting to AP...")
while not esp.is_connected:
    try:
        esp.connect_AP(ssid, password)
    except OSError as e:
        print("could not connect to AP, retrying: ", e)
        continue
print("Connected to", esp.ap_info.ssid, "\tRSSI:", esp.ap_info.rssi)
print("My IP address is", esp.ipv4_address)
print("IP lookup adafruit.com: %s" % esp.pretty_ip(esp.get_host_by_name("adafruit.com")))
print("Ping google.com: %d ms" % esp.ping("google.com"))

# esp._debug = True
print("Fetching text from", TEXT_URL)
r = requests.get(TEXT_URL)
print("-" * 40)
print(r.text)
print("-" * 40)
r.close()

print()
print("Fetching json from", JSON_URL)
r = requests.get(JSON_URL)
print("-" * 40)
print(r.json())
print("-" * 40)
r.close()

print("Done!")

# SPDX-FileCopyrightText: 2019 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

from os import getenv

import adafruit_connection_manager
import adafruit_requests
import board
import busio
from digitalio import DigitalInOut

from adafruit_esp32spi import adafruit_esp32spi

# Get wifi details and more from a settings.toml file
# tokens used by this Demo: CIRCUITPY_WIFI_SSID, CIRCUITPY_WIFI_PASSWORD
ssid = getenv("CIRCUITPY_WIFI_SSID")
password = getenv("CIRCUITPY_WIFI_PASSWORD")

print("ESP32 SPI webclient test")

TEXT_URL = "http://wifitest.adafruit.com/testwifi/index.html"
JSON_URL = "http://wifitest.adafruit.com/testwifi/sample.json"


# If you are using a board with pre-defined ESP32 Pins:
esp32_cs = DigitalInOut(board.ESP_CS)
esp32_ready = DigitalInOut(board.ESP_BUSY)
esp32_reset = DigitalInOut(board.ESP_RESET)

# If you have an AirLift Shield:
# esp32_cs = DigitalInOut(board.D10)
# esp32_ready = DigitalInOut(board.D7)
# esp32_reset = DigitalInOut(board.D5)

# If you have an AirLift Featherwing or ItsyBitsy Airlift:
# esp32_cs = DigitalInOut(board.D13)
# esp32_ready = DigitalInOut(board.D11)
# esp32_reset = DigitalInOut(board.D12)

# If you have an externally connected ESP32:
# NOTE: You may need to change the pins to reflect your wiring
# esp32_cs = DigitalInOut(board.D9)
# esp32_ready = DigitalInOut(board.D10)
# esp32_reset = DigitalInOut(board.D5)

# Secondary (SCK1) SPI used to connect to WiFi board on Arduino Nano Connect RP2040
if "SCK1" in dir(board):
    spi = busio.SPI(board.SCK1, board.MOSI1, board.MISO1)
else:
    spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
esp = adafruit_esp32spi.ESP_SPIcontrol(spi, esp32_cs, esp32_ready, esp32_reset)

pool = adafruit_connection_manager.get_radio_socketpool(esp)
ssl_context = adafruit_connection_manager.get_radio_ssl_context(esp)
requests = adafruit_requests.Session(pool, ssl_context)

if esp.status == adafruit_esp32spi.WL_IDLE_STATUS:
    print("ESP32 found and in idle mode")
print("Firmware vers.", esp.firmware_version)
print("MAC addr:", ":".join("%02X" % byte for byte in esp.MAC_address))

for ap in esp.scan_networks():
    print("\t%-23s RSSI: %d" % (ap.ssid, ap.rssi))

print("Connecting to AP...")
while not esp.is_connected:
    try:
        esp.connect_AP(ssid, password)
    except OSError as e:
        print("could not connect to AP, retrying: ", e)
        continue
print("Connected to", esp.ap_info.ssid, "\tRSSI:", esp.ap_info.rssi)
print("My IP address is", esp.ipv4_address)
print("IP lookup adafruit.com: %s" % esp.pretty_ip(esp.get_host_by_name("adafruit.com")))
print("Ping google.com: %d ms" % esp.ping("google.com"))

# esp._debug = True
print("Fetching text from", TEXT_URL)
r = requests.get(TEXT_URL)
print("-" * 40)
print(r.text)
print("-" * 40)
r.close()

print()
print("Fetching json from", JSON_URL)
r = requests.get(JSON_URL)
print("-" * 40)
print(r.json())
print("-" * 40)
r.close()

print("Done!")

And save it to your board, with the name code.py.

Don't forget you'll also need to create the settings.toml file as seen above, with your WiFi ssid and password.

In a serial console, you should see something like the following. For more information about connecting with a serial console, view the guide Connecting to the Serial Console.

Copy Text

>>> import wifitest
ESP32 SPI webclient test
ESP32 found and in idle mode
Firmware vers. 1.7.5
MAC addr: 24:C9:DC:BD:0F:3F
	HomeNetwork             RSSI: -46
	HomeNetwork             RSSI: -76
	Fios-12345              RSSI: -92
	FiOS-AB123              RSSI: -92
	NETGEAR53               RSSI: -93
Connecting to AP...
Connected to HomeNetwork 	RSSI: -45
My IP address is 192.168.1.245
IP lookup adafruit.com: 104.20.39.240
Ping google.com: 30 ms
Fetching text from http://wifitest.adafruit.com/testwifi/index.html
----------------------------------------
This is a test of Adafruit WiFi!
If you can read this, its working :)
----------------------------------------

Fetching json from http://wifitest.adafruit.com/testwifi/sample.json
----------------------------------------
{'fun': True, 'company': 'Adafruit', 'founded': 2005, 'primes': [2, 3, 5], 'pi': 3.14, 'mixed': [False, None, 3, True, 2.7, 'cheese']}
----------------------------------------
Done!

>>> import wifitest
ESP32 SPI webclient test
ESP32 found and in idle mode
Firmware vers. 1.7.5
MAC addr: 24:C9:DC:BD:0F:3F
	HomeNetwork             RSSI: -46
	HomeNetwork             RSSI: -76
	Fios-12345              RSSI: -92
	FiOS-AB123              RSSI: -92
	NETGEAR53               RSSI: -93
Connecting to AP...
Connected to HomeNetwork 	RSSI: -45
My IP address is 192.168.1.245
IP lookup adafruit.com: 104.20.39.240
Ping google.com: 30 ms
Fetching text from http://wifitest.adafruit.com/testwifi/index.html
----------------------------------------
This is a test of Adafruit WiFi!
If you can read this, its working :)
----------------------------------------

Fetching json from http://wifitest.adafruit.com/testwifi/sample.json
----------------------------------------
{'fun': True, 'company': 'Adafruit', 'founded': 2005, 'primes': [2, 3, 5], 'pi': 3.14, 'mixed': [False, None, 3, True, 2.7, 'cheese']}
----------------------------------------
Done!

Going over the example above, here's a breakdown of what the program is doing:

Initialize the ESP32 over SPI using the SPI port and 3 control pins:

Download File

Copy Code

esp32_cs = DigitalInOut(board.ESP_CS)
esp32_ready = DigitalInOut(board.ESP_BUSY)
esp32_reset = DigitalInOut(board.ESP_RESET)

#...

else:
    spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
esp = adafruit_esp32spi.ESP_SPIcontrol(spi, esp32_cs, esp32_ready, esp32_reset)

esp32_cs = DigitalInOut(board.ESP_CS)
esp32_ready = DigitalInOut(board.ESP_BUSY)
esp32_reset = DigitalInOut(board.ESP_RESET)

#...

else:
    spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
esp = adafruit_esp32spi.ESP_SPIcontrol(spi, esp32_cs, esp32_ready, esp32_reset)

Get the socket pool and the SSL context, and then tell the adafruit_requests library about them.

Download File

Copy Code

pool = adafruit_connection_manager.get_radio_socketpool(esp)
ssl_context = adafruit_connection_manager.get_radio_ssl_context(esp)
requests = adafruit_requests.Session(pool, ssl_context)

pool = adafruit_connection_manager.get_radio_socketpool(esp)
ssl_context = adafruit_connection_manager.get_radio_ssl_context(esp)
requests = adafruit_requests.Session(pool, ssl_context)

Verify an ESP32 is found, checks the firmware and MAC address

Download File

Copy Code

if esp.status == adafruit_esp32spi.WL_IDLE_STATUS:
    print("ESP32 found and in idle mode")
print("Firmware vers.", esp.firmware_version)
print("MAC addr:", ":".join("%02X" % byte for byte in esp.MAC_address))

if esp.status == adafruit_esp32spi.WL_IDLE_STATUS:
    print("ESP32 found and in idle mode")
print("Firmware vers.", esp.firmware_version)
print("MAC addr:", ":".join("%02X" % byte for byte in esp.MAC_address))

Perform a scan of all access points it can see and print out the name and signal strength.

Download File

Copy Code

for ap in esp.scan_networks():
    print("\t%-23s RSSI: %d" % (ap.ssid, ap.rssi))

for ap in esp.scan_networks():
    print("\t%-23s RSSI: %d" % (ap.ssid, ap.rssi))

Connect to the AP we've defined here, then print out the local IP address. Then attempt to do a domain name lookup and ping google.com to check network connectivity. (Note sometimes the ping fails or takes a while; this isn't a big deal.)

Download File

Copy Code

print("Connecting to AP...")
while not esp.is_connected:
    try:
        esp.connect_AP(ssid, password)
    except OSError as e:
        print("could not connect to AP, retrying: ", e)
        continue
print("Connected to", esp.ap_info.ssid, "\tRSSI:", esp.ap_info.rssi)
print("My IP address is", esp.ipv4_address)
print(
    "IP lookup adafruit.com: %s" % esp.pretty_ip(esp.get_host_by_name("adafruit.com"))
)

print("Connecting to AP...")
while not esp.is_connected:
    try:
        esp.connect_AP(ssid, password)
    except OSError as e:
        print("could not connect to AP, retrying: ", e)
        continue
print("Connected to", esp.ap_info.ssid, "\tRSSI:", esp.ap_info.rssi)
print("My IP address is", esp.ipv4_address)
print(
    "IP lookup adafruit.com: %s" % esp.pretty_ip(esp.get_host_by_name("adafruit.com"))
)

Now we're getting to the really interesting part of the example program. We've written a library for web fetching web data, named adafruit_requests. It is a lot like the regular Python library named requests. This library allows you to send HTTP and HTTPS requests easily and provides helpful methods for parsing the response from the server.

Here is the part of the example program is fetching text data from a URL.

Download File

Copy Code

TEXT_URL = "http://wifitest.adafruit.com/testwifi/index.html"  # Further up in the program

# ...

print("Fetching text from", TEXT_URL)
r = requests.get(TEXT_URL)
print('-' * 40)
print(r.text)
print('-' * 40)
r.close()

TEXT_URL = "http://wifitest.adafruit.com/testwifi/index.html"  # Further up in the program

# ...

print("Fetching text from", TEXT_URL)
r = requests.get(TEXT_URL)
print('-' * 40)
print(r.text)
print('-' * 40)
r.close()

Finally, here the program is fetching some JSON data. The adafruit_requests library will parse the JSON into a Python dictionary whose structure is the same as the structure of the JSON.

Download File

Copy Code

JSON_URL = "http://wifitest.adafruit.com/testwifi/sample.json"   # Further up in the program

# ...

print("Fetching json from", JSON_URL)
r = requests.get(JSON_URL)
print('-' * 40)
print(r.json())
print('-' * 40)
r.close()

JSON_URL = "http://wifitest.adafruit.com/testwifi/sample.json"   # Further up in the program

# ...

print("Fetching json from", JSON_URL)
r = requests.get(JSON_URL)
print('-' * 40)
print(r.json())
print('-' * 40)
r.close()

Advanced Requests Usage

Want to send custom HTTP headers, parse the response as raw bytes, or handle a response's http status code in your CircuitPython code?

We've written an example to show advanced usage of the requests module below.

To use with CircuitPython, you need to first install a few libraries, into the lib folder on your CIRCUITPY drive. Then you need to update code.py with the example script.

Download Project Bundle

Copy Code

# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

import os

import adafruit_connection_manager
import board
import busio
from adafruit_esp32spi import adafruit_esp32spi
from digitalio import DigitalInOut

import adafruit_requests

# Get WiFi details, ensure these are setup in settings.toml
ssid = os.getenv("CIRCUITPY_WIFI_SSID")
password = os.getenv("CIRCUITPY_WIFI_PASSWORD")

# If you are using a board with pre-defined ESP32 Pins:
esp32_cs = DigitalInOut(board.ESP_CS)
esp32_ready = DigitalInOut(board.ESP_BUSY)
esp32_reset = DigitalInOut(board.ESP_RESET)

# If you have an externally connected ESP32:
# esp32_cs = DigitalInOut(board.D9)
# esp32_ready = DigitalInOut(board.D10)
# esp32_reset = DigitalInOut(board.D5)

# If you have an AirLift Featherwing or ItsyBitsy Airlift:
# esp32_cs = DigitalInOut(board.D13)
# esp32_ready = DigitalInOut(board.D11)
# esp32_reset = DigitalInOut(board.D12)

spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
radio = adafruit_esp32spi.ESP_SPIcontrol(spi, esp32_cs, esp32_ready, esp32_reset)

print("Connecting to AP...")
while not radio.is_connected:
    try:
        radio.connect_AP(ssid, password)
    except RuntimeError as e:
        print("could not connect to AP, retrying: ", e)
        continue
print("Connected to", str(radio.ap_info.ssid, "utf-8"), "\tRSSI:", radio.ap_info.rssi)

# Initialize a requests session
pool = adafruit_connection_manager.get_radio_socketpool(radio)
ssl_context = adafruit_connection_manager.get_radio_ssl_context(radio)
requests = adafruit_requests.Session(pool, ssl_context)

JSON_GET_URL = "https://httpbin.org/get"

# Define a custom header as a dict.
headers = {"user-agent": "blinka/1.0.0"}

print("Fetching JSON data from %s..." % JSON_GET_URL)
with requests.get(JSON_GET_URL, headers=headers) as response:
    print("-" * 60)

    json_data = response.json()
    headers = json_data["headers"]
    print("Response's Custom User-Agent Header: {0}".format(headers["User-Agent"]))
    print("-" * 60)

    # Read Response's HTTP status code
    print("Response HTTP Status Code: ", response.status_code)
    print("-" * 60)

# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

import os

import adafruit_connection_manager
import board
import busio
from adafruit_esp32spi import adafruit_esp32spi
from digitalio import DigitalInOut

import adafruit_requests

# Get WiFi details, ensure these are setup in settings.toml
ssid = os.getenv("CIRCUITPY_WIFI_SSID")
password = os.getenv("CIRCUITPY_WIFI_PASSWORD")

# If you are using a board with pre-defined ESP32 Pins:
esp32_cs = DigitalInOut(board.ESP_CS)
esp32_ready = DigitalInOut(board.ESP_BUSY)
esp32_reset = DigitalInOut(board.ESP_RESET)

# If you have an externally connected ESP32:
# esp32_cs = DigitalInOut(board.D9)
# esp32_ready = DigitalInOut(board.D10)
# esp32_reset = DigitalInOut(board.D5)

# If you have an AirLift Featherwing or ItsyBitsy Airlift:
# esp32_cs = DigitalInOut(board.D13)
# esp32_ready = DigitalInOut(board.D11)
# esp32_reset = DigitalInOut(board.D12)

spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
radio = adafruit_esp32spi.ESP_SPIcontrol(spi, esp32_cs, esp32_ready, esp32_reset)

print("Connecting to AP...")
while not radio.is_connected:
    try:
        radio.connect_AP(ssid, password)
    except RuntimeError as e:
        print("could not connect to AP, retrying: ", e)
        continue
print("Connected to", str(radio.ap_info.ssid, "utf-8"), "\tRSSI:", radio.ap_info.rssi)

# Initialize a requests session
pool = adafruit_connection_manager.get_radio_socketpool(radio)
ssl_context = adafruit_connection_manager.get_radio_ssl_context(radio)
requests = adafruit_requests.Session(pool, ssl_context)

JSON_GET_URL = "https://httpbin.org/get"

# Define a custom header as a dict.
headers = {"user-agent": "blinka/1.0.0"}

print("Fetching JSON data from %s..." % JSON_GET_URL)
with requests.get(JSON_GET_URL, headers=headers) as response:
    print("-" * 60)

    json_data = response.json()
    headers = json_data["headers"]
    print("Response's Custom User-Agent Header: {0}".format(headers["User-Agent"]))
    print("-" * 60)

    # Read Response's HTTP status code
    print("Response HTTP Status Code: ", response.status_code)
    print("-" * 60)

Your CIRCUITPY drive should now look similar to the following image:

WiFi Manager

The way the examples above connect to WiFi works but it's a little finicky. Since WiFi is not necessarily so reliable, you may have disconnects and need to reconnect. For more advanced uses, we recommend using the WiFiManager class. It will wrap the connection/status/requests loop for you - reconnecting if WiFi drops, resetting the ESP32 if it gets into a bad state, etc.

Here's a more advanced example that shows using the WiFiManager and also how to fetch the current time from a web source.

Download Project Bundle

Copy Code

# SPDX-FileCopyrightText: 2019 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

import time
from os import getenv

import board
import busio
import neopixel
import rtc
from digitalio import DigitalInOut

from adafruit_esp32spi import adafruit_esp32spi
from adafruit_esp32spi.adafruit_esp32spi_wifimanager import WiFiManager

# Get wifi details and more from a settings.toml file
# tokens used by this Demo: CIRCUITPY_WIFI_SSID, CIRCUITPY_WIFI_PASSWORD
ssid = getenv("CIRCUITPY_WIFI_SSID")
password = getenv("CIRCUITPY_WIFI_PASSWORD")

print("ESP32 local time")

TIME_API = "http://worldtimeapi.org/api/ip"

# If you are using a board with pre-defined ESP32 Pins:
esp32_cs = DigitalInOut(board.ESP_CS)
esp32_ready = DigitalInOut(board.ESP_BUSY)
esp32_reset = DigitalInOut(board.ESP_RESET)

# If you have an externally connected ESP32:
# esp32_cs = DigitalInOut(board.D9)
# esp32_ready = DigitalInOut(board.D10)
# esp32_reset = DigitalInOut(board.D5)

# Secondary (SCK1) SPI used to connect to WiFi board on Arduino Nano Connect RP2040
if "SCK1" in dir(board):
    spi = busio.SPI(board.SCK1, board.MOSI1, board.MISO1)
else:
    spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
esp = adafruit_esp32spi.ESP_SPIcontrol(spi, esp32_cs, esp32_ready, esp32_reset)

"""Use below for Most Boards"""
status_pixel = neopixel.NeoPixel(board.NEOPIXEL, 1, brightness=0.2)
"""Uncomment below for ItsyBitsy M4"""
# status_pixel = dotstar.DotStar(board.APA102_SCK, board.APA102_MOSI, 1, brightness=0.2)
"""Uncomment below for an externally defined RGB LED (including Arduino Nano Connect)"""
# import adafruit_rgbled
# from adafruit_esp32spi import PWMOut
# RED_LED = PWMOut.PWMOut(esp, 26)
# GREEN_LED = PWMOut.PWMOut(esp, 27)
# BLUE_LED = PWMOut.PWMOut(esp, 25)
# status_pixel = adafruit_rgbled.RGBLED(RED_LED, BLUE_LED, GREEN_LED)

wifi = WiFiManager(esp, ssid, password, status_pixel=status_pixel)

the_rtc = rtc.RTC()

response = None
while True:
    try:
        print("Fetching json from", TIME_API)
        response = wifi.get(TIME_API)
        break
    except OSError as e:
        print("Failed to get data, retrying\n", e)
        continue

json = response.json()
current_time = json["datetime"]
the_date, the_time = current_time.split("T")
year, month, mday = (int(x) for x in the_date.split("-"))
the_time = the_time.split(".")[0]
hours, minutes, seconds = (int(x) for x in the_time.split(":"))

# We can also fill in these extra nice things
year_day = json["day_of_year"]
week_day = json["day_of_week"]
is_dst = json["dst"]

now = time.struct_time((year, month, mday, hours, minutes, seconds, week_day, year_day, is_dst))
print(now)
the_rtc.datetime = now

while True:
    print(time.localtime())
    time.sleep(1)

# SPDX-FileCopyrightText: 2019 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

import time
from os import getenv

import board
import busio
import neopixel
import rtc
from digitalio import DigitalInOut

from adafruit_esp32spi import adafruit_esp32spi
from adafruit_esp32spi.adafruit_esp32spi_wifimanager import WiFiManager

# Get wifi details and more from a settings.toml file
# tokens used by this Demo: CIRCUITPY_WIFI_SSID, CIRCUITPY_WIFI_PASSWORD
ssid = getenv("CIRCUITPY_WIFI_SSID")
password = getenv("CIRCUITPY_WIFI_PASSWORD")

print("ESP32 local time")

TIME_API = "http://worldtimeapi.org/api/ip"

# If you are using a board with pre-defined ESP32 Pins:
esp32_cs = DigitalInOut(board.ESP_CS)
esp32_ready = DigitalInOut(board.ESP_BUSY)
esp32_reset = DigitalInOut(board.ESP_RESET)

# If you have an externally connected ESP32:
# esp32_cs = DigitalInOut(board.D9)
# esp32_ready = DigitalInOut(board.D10)
# esp32_reset = DigitalInOut(board.D5)

# Secondary (SCK1) SPI used to connect to WiFi board on Arduino Nano Connect RP2040
if "SCK1" in dir(board):
    spi = busio.SPI(board.SCK1, board.MOSI1, board.MISO1)
else:
    spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
esp = adafruit_esp32spi.ESP_SPIcontrol(spi, esp32_cs, esp32_ready, esp32_reset)

"""Use below for Most Boards"""
status_pixel = neopixel.NeoPixel(board.NEOPIXEL, 1, brightness=0.2)
"""Uncomment below for ItsyBitsy M4"""
# status_pixel = dotstar.DotStar(board.APA102_SCK, board.APA102_MOSI, 1, brightness=0.2)
"""Uncomment below for an externally defined RGB LED (including Arduino Nano Connect)"""
# import adafruit_rgbled
# from adafruit_esp32spi import PWMOut
# RED_LED = PWMOut.PWMOut(esp, 26)
# GREEN_LED = PWMOut.PWMOut(esp, 27)
# BLUE_LED = PWMOut.PWMOut(esp, 25)
# status_pixel = adafruit_rgbled.RGBLED(RED_LED, BLUE_LED, GREEN_LED)

wifi = WiFiManager(esp, ssid, password, status_pixel=status_pixel)

the_rtc = rtc.RTC()

response = None
while True:
    try:
        print("Fetching json from", TIME_API)
        response = wifi.get(TIME_API)
        break
    except OSError as e:
        print("Failed to get data, retrying\n", e)
        continue

json = response.json()
current_time = json["datetime"]
the_date, the_time = current_time.split("T")
year, month, mday = (int(x) for x in the_date.split("-"))
the_time = the_time.split(".")[0]
hours, minutes, seconds = (int(x) for x in the_time.split(":"))

# We can also fill in these extra nice things
year_day = json["day_of_year"]
week_day = json["day_of_week"]
is_dst = json["dst"]

now = time.struct_time((year, month, mday, hours, minutes, seconds, week_day, year_day, is_dst))
print(now)
the_rtc.datetime = now

while True:
    print(time.localtime())
    time.sleep(1)

Further Information

For more information on the basics of doing networking in CircuitPython, see this guide:

Networking in CircuitPython

By Anne Barela

View Guide

Page last edited March 08, 2024

Text editor powered by tinymce.

Adafruit IO Setup

Feed Setup

If you do not already have an Adafruit IO account set up, head over to io.adafruit.com to link your Adafruit.com account to Adafruit IO.

The first step is to create a new Adafruit IO feed to hold the data from the PyPortal's temperature sensor. Navigate to the feeds page on Adafruit IO. Then click Actions -> Create New Feed, and name this feed weight.

If you do not already know how to create a feed, head over to Adafruit IO Basics: Feeds.

Build an Adafruit IO Dashboard

Next, you'll create a dashboard to display the values from the feed you created.

If you do not know how to create or use Dashboards in Adafruit IO, head over to the Adafruit IO Basics: Dashboards guide.

Adding a Gauge Block

To display the values from your Scale, you'll add a gauge block to your dashboard. This blocks displays values within a fixed range and can serve as a visual indication for if the values are too low or high.

hacks_temperature___humidity_adafruit_io_weather_IO_-_Feather_Huzzah___ADT7410_Gauge.png

From the dashboard you created dashboard, Select the Gauge block.

Select the weight feed

The code will be sending data from the scale in grams.

Set the Block Title to Scale

Set the Gauge Min Value to 0

Set the Gauge Max Value to 500

and Set the Gauge Label to grams

Adding a Line Chart

While displaying the current value of the weight is useful, Adafruit IO stores data so you can monitor how it changes a long period of time. Alternatively, you can visualize it in real-time To do this, we'll use the Line Chart block.

Select the weight feed.

Give the line chart a name, and set it to display live history (you can change to display a longer time period this by editing this block)

Your final dashboard should look like the following:

If you want to customize your dashboard - add more blocks to the dashboard, or resize the existing blocks.

Obtain Adafruit IO Key

You are also going to need your Adafruit IO username and secret API key.

Navigate to your profile and click the View AIO Key button to retrieve them. Write them down in a safe place, you'll need them for the next step.

Page last edited March 08, 2024

Text editor powered by tinymce.

CircuitPython Code

CircuitPython Library Installation

To interface your PyPortal with the DYMO scale and the internet - you'll need to install the Adafruit CircuitPython Adafruit IO and the Adafruit CircuitPython DymoScale libraries on your PyPortal.

First make sure you are running the latest version of Adafruit CircuitPython for your board.

Next you'll need to install the necessary libraries to use the hardware--carefully follow the steps to find and install these libraries from Adafruit's CircuitPython library bundle matching your version of CircuitPython. PyPortal requires at least CircuitPython version 4.0.0.

Before continuing make sure your board's lib folder has the following files and folders copied over.

adafruit_io
adafruit_dymoscale
adafruit_esp32spi
adafruit_bus_device
adafruit_bitmap_font
adafruit_display_text
neopixel.mpy

settings.toml File Setup

You'll need your Adafruit IO username, and Adafruit IO key. Head to io.adafruit.com and simply click the View AIO Key link on the left hand side of the Adafruit IO page to get this information.

Then, add them to the settings.toml file you set up previously.

Download File

Copy Code

CIRCUITPY_WIFI_SSID = "your_wifi_ssid"
CIRCUITPY_WIFI_PASSWORD = "your_wifi_password"
ADAFRUIT_AIO_USERNAME="my_username"
ADAFRUIT_AIO_KEY="my_key"

CIRCUITPY_WIFI_SSID = "your_wifi_ssid"
CIRCUITPY_WIFI_PASSWORD = "your_wifi_password"
ADAFRUIT_AIO_USERNAME="my_username"
ADAFRUIT_AIO_KEY="my_key"

Add CircuitPython Code and Project Assets

In the embedded code element below, click on the Download Project Bundle button, and save the .zip archive file to your computer.

Then, uncompress the .zip file, it will unpack to a folder named PyPortal_IOT_Scale.

Copy the contents of the PyPortal_IOT_Scale directory to your PyPortal CIRCUITPY drive.

Make sure to save the fonts (Helvetica-Bold-16.bdf and Helvetica-Bold-36.bdf) into the fonts folder on the CIRCUITPY volume.

Download Project Bundle

Copy Code

# SPDX-FileCopyrightText: 2019 Brent Rubell for Adafruit Industries
#
# SPDX-License-Identifier: MIT

"""
PyPortal Smart Scale
an internet of things smart-scale for Adafruit IO

Brent Rubell for Adafruit Industries, 2019
"""

from os import getenv
import time
import board
import adafruit_dymoscale
import busio
import digitalio

import displayio
from adafruit_display_text.label import Label
from adafruit_bitmap_font import bitmap_font

from adafruit_esp32spi import adafruit_esp32spi, adafruit_esp32spi_wifimanager
import neopixel
from adafruit_io.adafruit_io import IO_HTTP

# Get WiFi details and Adafruit IO keys, ensure these are setup in settings.toml
# (visit io.adafruit.com if you need to create an account, or if you need your Adafruit IO key.)
ssid = getenv("CIRCUITPY_WIFI_SSID")
password = getenv("CIRCUITPY_WIFI_PASSWORD")
aio_username = getenv("ADAFRUIT_AIO_USERNAME")
aio_key = getenv("ADAFRUIT_AIO_KEY")

if None in [ssid, password, aio_username, aio_key]:
    raise RuntimeError(
        "WiFi and Adafruit IO settings are kept in settings.toml, "
        "please add them there. The settings file must contain "
        "'CIRCUITPY_WIFI_SSID', 'CIRCUITPY_WIFI_PASSWORD', "
        "'ADAFRUIT_AIO_USERNAME' and 'ADAFRUIT_AIO_KEY' at a minimum."
    )

# the current working directory (where this file is)
cwd = ("/"+__file__).rsplit('/', 1)[0]
large_font = cwd+"/fonts/Helvetica-Bold-36.bdf"
small_font = cwd+"/fonts/Helvetica-Bold-16.bdf"

root_group = displayio.Group()
print('loading fonts...')
weight_font = bitmap_font.load_font(large_font)
weight_font.load_glyphs(b'0123456789.goz-SCALEROIO ')

text_font = bitmap_font.load_font(small_font)
text_font.load_glyphs(b'sendig!t.')

print('making labels...')
weight_label = Label(weight_font)
weight_label.x = 75
weight_label.y = 120
root_group.append(weight_label)
weight_label.text = "---"

title_label = Label(weight_font)
title_label.x = 65
title_label.y = 20
root_group.append(title_label)
title_label.text = "IO SCALE"

text_label = Label(text_font)
text_label.x = 100
text_label.y = 200
text_label.color = 0xFFFFFF
root_group.append(text_label)

board.DISPLAY.root_group = root_group

# PyPortal ESP32 Setup
esp32_cs = digitalio.DigitalInOut(board.ESP_CS)
esp32_ready = digitalio.DigitalInOut(board.ESP_BUSY)
esp32_reset = digitalio.DigitalInOut(board.ESP_RESET)
spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
esp = adafruit_esp32spi.ESP_SPIcontrol(spi, esp32_cs, esp32_ready, esp32_reset)
status_pixel = neopixel.NeoPixel(board.NEOPIXEL, 1, brightness=0.2)
wifi = adafruit_esp32spi_wifimanager.WiFiManager(esp, ssid, password, status_pixel=status_pixel)

# Create an instance of the IO_HTTP client
io = IO_HTTP(aio_username, aio_key, wifi)

# Get the weight feed from IO
weight_feed = io.get_feed('weight')

# initialize the dymo scale
units_pin = digitalio.DigitalInOut(board.D3)
units_pin.switch_to_output()
dymo = adafruit_dymoscale.DYMOScale(board.D4, units_pin)

# take a reading of the current time, used for toggling the device out of sleep
time_stamp = time.monotonic()

while True:
    try:
        reading = dymo.weight
        text = "%0.1f g"%reading.weight
        print(text)
        weight_label.text = text
        weight_label.color = 0xFFFFFF
        try:
            print('Sending to Adafruit IO...')
            text_label.text = 'sending...'
            # send data to Adafruit IO (rounded to one decimal place)
            io.send_data(weight_feed['key'], round(reading.weight, 1))
        except (ValueError, RuntimeError, ConnectionError, OSError) as e:
            print("failed to send data..retrying...")
            wifi.reset()
            continue
        print('Data sent!')
        text_label.text = 'sent!'
        # to avoid sleep mode, toggle the units pin every 2mins.
        if (time.monotonic() - time_stamp) > 120:
            print('toggling units button')
            dymo.toggle_unit_button()
            # reset the time
            time_stamp = time.monotonic()
    except RuntimeError as e:
        weight_label.text = "SCALE\nERROR"
        weight_label.color = 0xFF0000
        print("Error: ", e)

# SPDX-FileCopyrightText: 2019 Brent Rubell for Adafruit Industries
#
# SPDX-License-Identifier: MIT

"""
PyPortal Smart Scale
an internet of things smart-scale for Adafruit IO

Brent Rubell for Adafruit Industries, 2019
"""

from os import getenv
import time
import board
import adafruit_dymoscale
import busio
import digitalio

import displayio
from adafruit_display_text.label import Label
from adafruit_bitmap_font import bitmap_font

from adafruit_esp32spi import adafruit_esp32spi, adafruit_esp32spi_wifimanager
import neopixel
from adafruit_io.adafruit_io import IO_HTTP

# Get WiFi details and Adafruit IO keys, ensure these are setup in settings.toml
# (visit io.adafruit.com if you need to create an account, or if you need your Adafruit IO key.)
ssid = getenv("CIRCUITPY_WIFI_SSID")
password = getenv("CIRCUITPY_WIFI_PASSWORD")
aio_username = getenv("ADAFRUIT_AIO_USERNAME")
aio_key = getenv("ADAFRUIT_AIO_KEY")

if None in [ssid, password, aio_username, aio_key]:
    raise RuntimeError(
        "WiFi and Adafruit IO settings are kept in settings.toml, "
        "please add them there. The settings file must contain "
        "'CIRCUITPY_WIFI_SSID', 'CIRCUITPY_WIFI_PASSWORD', "
        "'ADAFRUIT_AIO_USERNAME' and 'ADAFRUIT_AIO_KEY' at a minimum."
    )

# the current working directory (where this file is)
cwd = ("/"+__file__).rsplit('/', 1)[0]
large_font = cwd+"/fonts/Helvetica-Bold-36.bdf"
small_font = cwd+"/fonts/Helvetica-Bold-16.bdf"

root_group = displayio.Group()
print('loading fonts...')
weight_font = bitmap_font.load_font(large_font)
weight_font.load_glyphs(b'0123456789.goz-SCALEROIO ')

text_font = bitmap_font.load_font(small_font)
text_font.load_glyphs(b'sendig!t.')

print('making labels...')
weight_label = Label(weight_font)
weight_label.x = 75
weight_label.y = 120
root_group.append(weight_label)
weight_label.text = "---"

title_label = Label(weight_font)
title_label.x = 65
title_label.y = 20
root_group.append(title_label)
title_label.text = "IO SCALE"

text_label = Label(text_font)
text_label.x = 100
text_label.y = 200
text_label.color = 0xFFFFFF
root_group.append(text_label)

board.DISPLAY.root_group = root_group

# PyPortal ESP32 Setup
esp32_cs = digitalio.DigitalInOut(board.ESP_CS)
esp32_ready = digitalio.DigitalInOut(board.ESP_BUSY)
esp32_reset = digitalio.DigitalInOut(board.ESP_RESET)
spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
esp = adafruit_esp32spi.ESP_SPIcontrol(spi, esp32_cs, esp32_ready, esp32_reset)
status_pixel = neopixel.NeoPixel(board.NEOPIXEL, 1, brightness=0.2)
wifi = adafruit_esp32spi_wifimanager.WiFiManager(esp, ssid, password, status_pixel=status_pixel)

# Create an instance of the IO_HTTP client
io = IO_HTTP(aio_username, aio_key, wifi)

# Get the weight feed from IO
weight_feed = io.get_feed('weight')

# initialize the dymo scale
units_pin = digitalio.DigitalInOut(board.D3)
units_pin.switch_to_output()
dymo = adafruit_dymoscale.DYMOScale(board.D4, units_pin)

# take a reading of the current time, used for toggling the device out of sleep
time_stamp = time.monotonic()

while True:
    try:
        reading = dymo.weight
        text = "%0.1f g"%reading.weight
        print(text)
        weight_label.text = text
        weight_label.color = 0xFFFFFF
        try:
            print('Sending to Adafruit IO...')
            text_label.text = 'sending...'
            # send data to Adafruit IO (rounded to one decimal place)
            io.send_data(weight_feed['key'], round(reading.weight, 1))
        except (ValueError, RuntimeError, ConnectionError, OSError) as e:
            print("failed to send data..retrying...")
            wifi.reset()
            continue
        print('Data sent!')
        text_label.text = 'sent!'
        # to avoid sleep mode, toggle the units pin every 2mins.
        if (time.monotonic() - time_stamp) > 120:
            print('toggling units button')
            dymo.toggle_unit_button()
            # reset the time
            time_stamp = time.monotonic()
    except RuntimeError as e:
        weight_label.text = "SCALE\nERROR"
        weight_label.color = 0xFF0000
        print("Error: ", e)

This is what the final contents of the CIRCUITPY drive will look like:

Code Usage

Ensure that the scale's data pin is plugged into D3 on the PyPortal and the units button is plugged into D4 on the PyPortal.

Then, the PyPortal will display IOT Scale and should display the current weight shown on the scale's LCD display.

If your scale is displaying SCALE ERROR, the scale is not turned on yet. Press the power button (the button all the way on the left) to turn on the scale's power.

Since you're not running the scale off of batteries, you'll need to perform this step each time you disconnect/reset the PyPortal.

When you place something on the scale, the PyPortal's display will update with a new value and send it to Adafruit IO.

Every two minutes, the scale's LCD will switch between grams and ounces to avoid going into sleep mode (see the Removing the Auto Shut Off section below)

Page last edited March 08, 2024

Text editor powered by tinymce.

Sending Data to Adafruit.IO

Adafruit IO Usage

While the PyPortal can display measurements on its LCD - what if you're physically away from the scale or need to log weight data over a period of time?

How do we know that the weight data is being sent from the PyPortal to Adafruit IO?

Open the Adafruit IO Dashboard you created earlier. Notice that the fill and values of the gauge changes as values are sent from your PyPortal to Adafruit IO.

Then, leave the PyPortal running for a while and come back later to see new data appear on the line graph.

Page last edited March 08, 2024

Text editor powered by tinymce.

Code Walkthrough

Code Overview

To interface with the DYMO scale's data protocol, we wrote a CircuitPython library called Adafruit CircuitPython DymoScale.

To take a reading from the scale (the library returns the weight in grams), we call

Download File

Copy Code

reading = dymo.weight

reading = dymo.weight

Then, print out the weight of the reading to the REPL as well as the weight_label on the PyPortal's display:

Download File

Copy Code

text = "%0.1f g"%reading.weight
print(text)
weight_label.text = text
weight_label.color = 0xFFFFFF

text = "%0.1f g"%reading.weight
print(text)
weight_label.text = text
weight_label.color = 0xFFFFFF

Now that you have the data from the scale, it is time to send it to Adafruit IO. To do this, the code uses the send_data method from Adafruit IO CircuitPython.

For the weight on your dashboard to reflect what's displayed on the PyPortal the weight sent to IO is rounded to one decimal place.

Download File

Copy Code

print('Sending to Adafruit IO...')
text_label.color = 0xFFFFFF
text_label.text = 'Sending...'
# send data to Adafruit IO (rounded to one decimal place)
io.send_data(weight_feed['key'], round(reading.weight, 1))

print('Sending to Adafruit IO...')
text_label.color = 0xFFFFFF
text_label.text = 'Sending...'
# send data to Adafruit IO (rounded to one decimal place)
io.send_data(weight_feed['key'], round(reading.weight, 1))

That's it - sending data to Adafruit IO with CircuitPython is simple!

Removing the Auto Shut Off

The M-series DYMO scales have an automatic shut off "feature". The scale turns off after three minutes of inactivity. While this is a useful feature to preserve the scale's batteries - it causes the scale to turn off if we're measuring anything over a length of three minutes.

If you're measuring the volume of a mug of pour-over coffee or a bag of cat food - the scale will turn off.

Dymo M-Series Manual (http://download.dymo.com/dymo/user-guides/scales/M10_M25_UserGuide_en-US.pdf)

In the Wiring page, you soldered a wire onto the Grams/Ounces button and connected it to your PyPortal. We've included a method in the adafruit_dymoscale library called toggle_unit_button to simulate pressing the button for you.

When the dymo object is initialized in the code, the units_pin is provided to it along with the scale's data pin.

Download File

Copy Code

units_pin = digitalio.DigitalInOut(board.D3)
units_pin.switch_to_output()
dymo = adafruit_dymoscale.DYMOScale(board.D4, units_pin)

units_pin = digitalio.DigitalInOut(board.D3)
units_pin.switch_to_output()
dymo = adafruit_dymoscale.DYMOScale(board.D4, units_pin)

Then, the code takes a reference time reading with time.monotonic()

Download File

Copy Code

# take a reading of the current time, used for toggling the units button
time_stamp = time.monotonic()

# take a reading of the current time, used for toggling the units button
time_stamp = time.monotonic()

Each time the code runs through the while True loop, we'll check it against the current time. If it exceeds two minutes, the code toggles the unit button (dymo.toggle_unit_button()) and resets the timestamp by setting it to the current time.

Download File

Copy Code

# to avoid sleep mode, toggle the units pin every 2 mins.
if (time.monotonic() - time_stamp) > 120:
  print('toggling units button...')
  dymo.toggle_unit_button()
  # reset the time stamp
  time_stamp = time.monotonic()

# to avoid sleep mode, toggle the units pin every 2 mins.
if (time.monotonic() - time_stamp) > 120:
  print('toggling units button...')
  dymo.toggle_unit_button()
  # reset the time stamp
  time_stamp = time.monotonic()