Are you familiar with block-based programming and trying to make the jump to Python?

You're in luck! EduBlocks is a web-based programming interface that is making the transition from block-based programming languages like Scratch to the syntax-based language Python easier.

If you've never programmed before and are new to block-based programming altogether, check out the block-based language MakeCode first. There's a helpful guide on that here.

In this guide we will go through the EduBlocks editor interface and different code blocks.

Next, we'll see how to upload code to the Circuit Playground Express and troubleshoot any issues. The Circuit Playground Express (CPX) is a great introduction to coding and electronics. Click here to learn more!

Last, we will go over different applications and examples of how to program the CPX to blink an LED, switch NeoPixel colors with buttons, and lastly make a touch-based drum machine!

Adafruit Parts:

Optional parts:

Sound amplification parts:

• A speaker or amplifier with an 1/8" or 1/4" input

If using a speaker with 1/8" input:

If using an amp with 1/4" input:

To trigger drum sounds:

• Spare coins or other capacitive touch materials like aluminum foil or even fruit!

The quickest way to get started with EduBlocks is to jump right in! The programming language is web-based, which means there is no downloading necessary. Just head to the website below.

After entering the site, you will be taken to the EduBlocks project editor. This is where all the coding happens!

The EduBlocks user interface is the area on your screen where the CircuitPython program exists. The screen is divided into multiple sections, which have different functions, from picking blocks to code with, to downloading a CircuitPython file. We will go through the different elements of the interface

EduBlocks is a "block-based" programming language. This means instead of writing lines of code to program, we use "blocks". Each block has a specific category that describes what its purpose is. In EduBlocks, each block type corresponds to a library in CircuitPython.

Each CircuitPython program you run needs to have a lot of information to work. The reason CircuitPython is so simple to use is that most of that information is stored in other files and works in the background. These files are called libraries. 

For example the NeoPixel library allows us to control the NeoPixels on the board. Without importing the library, we cannot access the functionality.

Basic

Variables

Digital

Analog

Neopixel

Touch

Servo

Audio

PWM

Dotstar

Advanced

CPX Easy

Saving, Loading and Downloading Programs

Switching from CircuitPython Syntax Code to Blocks

Copy and Paste

• Need multiple blocks that are the same? Speed up your workflow by selecting blocks then copy and pasting them!

Using CPX Library with Other Libraries

EduBlocks is still in Beta mode, so it unfortunately doesn't have NeoPixel capabilities yet in the CPX Easy library. Thus to program NeoPixels, we must use the NeoPixel library. 

Knowing this, when we import both the CPX Easy and NeoPixel libraries, we get a "Value: pin in use" error because both libraries are trying to access the NeoPixels.*

To avoid errors like these when using the CPX Easy library, refrain from also using the NeoPixel library.

*This error would show up in the REPL if using a code editor such as Mu. See Troubleshooting section.

Now we'll set up the CPX for CircuitPython mode to be able to upload the code we write to the board.

If your CPX is already in CircuitPython mode, double check it is updated to the latest version. Check on the circuitpython.org site to see the latest version. You can find the current version by opening up the file boot_out.txt on the root directory of the CIRCUITPY drive.

You will know you are in CircuitPython mode if the drive CIRCUITPY shows up on your computer when connected via micro-B USB cable to your computer.

If your board doesn't have CircuitPython installed

If this is your first time using your CPX with CircuitPython or you see a drive entitled CPLAYBOOT, your board may not have CircuitPython installed yet. No worries. Follow the steps and extended guide below to switch to CircuitPython mode.

• First install or update CircuitPython. The latest file from circuitpython.org will be a .uf2 file.
• Next, plug the CPX to your a computer via micro-B USB cable and double click the reset button on the Circuit Playground Express (the CPX NeoPixels should turn green).
• Now drag the recently downloaded .uf2 file onto the CPLAYBOOT drive oon your computer.
• The drive should disappear from your File Explorer or Finder (depending on your operating system) and come back as CIRCUITPY.

Here is an extended guide on how to follow the above steps with images and pictures to help.

Running Your Program

Once you have CircuitPython installed, when you want to run your main.py file, copy it via your computer to the root directory of the CIRCUITPY drive.

Problems?

If issues are still arising while getting into CircuitPython mode, check out this troubleshooting guide.

Your Circuit Playground Express has a little red LED next to the USB port. It's labeled D13.

In EduBlocks, we are going to turn it on for half a second, then off for half a second, then back on etc. forever!

The Blinky LED Program

Downloading the Program and Uploading to the CPX

Once the blocks look good, click Download in the EduBlocks toolbar.

You may have to tell your browser you want to keep the file if asked. 

A file named main.py should show up in downloads.

With the CPX plugged into the computer, drag main.py to the CIRCUITPY drive.

The drive should now have the file on it and the code should be running!

Is the LED blinking on and off on your CPX?

Issues? Troubleshooting help here.

Here are the code files if you want to upload directly to EduBlocks or the CPX.

EduBlocks file:

CircuitPython Code:

import time
from adafruit_circuitplayground.express import cpx
while True:
  cpx.red_led = True
  time.sleep(0.5)
  cpx.red_led = False
  time.sleep(0.5)

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import time
from adafruit_circuitplayground.express import cpx
while True:
  cpx.red_led = True
  time.sleep(0.5)
  cpx.red_led = False
  time.sleep(0.5)

The Circuit Playground Express has two buttons. Button A is on the left and button B is on the right. These buttons can be used as inputs, which means you can use them to tell your board to do something when you press them.

In this example, we'll use the buttons of the CPX to change the colors of the NeoPixels. Button A will turn them red, and B will turn them blue.

The NeoPixel and Buttons Program

Library Import and NeoPixel Set Up

Creating Variables

Setting Up the Buttons

The While Loop:

Download the file and drag to the CPX.

Try it out!

When button A is pressed, NeoPixels should turn red.

When button B is pressed they should turn blue!

Here are the code files if you want to upload directly to EduBlocks or the CPX.

EduBlocks file:

CircuitPython Code:

np = None
button_a = None
button_b = None


from digitalio import *
import board
import neopixel
np = neopixel.NeoPixel(board.NEOPIXEL, 10, brightness = 0.2)
np.fill((0,0,0))
np.show()
button_a = DigitalInOut(board.BUTTON_A)
button_a.direction = Direction.INPUT
button_a.pull = Pull.DOWN
button_b = DigitalInOut(board.BUTTON_B)
button_b.direction = Direction.INPUT
button_b.pull = Pull.DOWN
while True:
  if button_a.value:
    np.fill((255,0,0))
    np.show()
  elif button_b.value:
    np.fill((0,0,255))
    np.show()

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np = None
button_a = None
button_b = None


from digitalio import *
import board
import neopixel
np = neopixel.NeoPixel(board.NEOPIXEL, 10, brightness = 0.2)
np.fill((0,0,0))
np.show()
button_a = DigitalInOut(board.BUTTON_A)
button_a.direction = Direction.INPUT
button_a.pull = Pull.DOWN
button_b = DigitalInOut(board.BUTTON_B)
button_b.direction = Direction.INPUT
button_b.pull = Pull.DOWN
while True:
  if button_a.value:
    np.fill((255,0,0))
    np.show()
  elif button_b.value:
    np.fill((0,0,255))
    np.show()

This lesson is a spin off of John Park's Drum Machine.

We can use the capacitive touch pads on the Circuit Playground Express as triggers and small .wav files for our drum sounds! 

Until now, we needed to code in CircuitPython to play sound files. Now with EduBlocks, all we need to do is drag a couple of blocks and we're good to go!

First, download the .zip file below, which contains all of the drum samples we'll be using. Save the file to your desktop or somewhere else easy to find, and then unzip it.

You can plug in your Circuit Playground Express, and then drag the drum files onto it. It shows up as the CIRCUITPY drive.

EduBlocks Code:

Importing Libraries and Defining Variables:

The Touchpads

Trigger the Sounds

Attach Conductive Materials with Alligator Clips to Capacitive Touch Pads:

Download the main.py file and drag to the CPX.

Try it out!

Sounds should be triggering when each coin is touched or held!

If you want to use your own sound files, you can! Record, sample, remix, or simply download files from a sound file sight, such as freesample.org. Then, to make sure you have the files converted to the proper specifications, check out this guide here that'll show you how! Spoiler alert: you'll need to make a small, 22Khz (or lower), 16 bit PCM, mono  .wav file!

Want to listen to your Drum Machine at body movin' volumes? No problem! Hook up an 1/8" or 1/4" phono output to the GND and A0 pads, then plug in to an amp or speaker! I tried it on a small speaker with an aux input and it sounded great!

Here are the code files if you want to upload directly to EduBlocks or the CPX.

EduBlocks file:

CircuitPython Code:

touch1 = None
touch2 = None
touch3 = None
touch4 = None
touch5 = None
touch6 = None
touch7 = None

BPM = None


import time
import board
import touchio
from digitalio import *
from adafruit_circuitplayground.express import cpx
BPM = .125
touch1 = touchio.TouchIn(board.A1)
touch2 = touchio.TouchIn(board.A2)
touch3 = touchio.TouchIn(board.A3)
touch4 = touchio.TouchIn(board.A4)
touch5 = touchio.TouchIn(board.A5)
touch6 = touchio.TouchIn(board.A6)
touch7 = touchio.TouchIn(board.A7)
while True:
  if touch1.value:
    cpx.play_file("bd_tek.wav")
    time.sleep(BPM)
  elif touch2.value:
    cpx.play_file("elec_hi_snare.wav")
    time.sleep(BPM)
  elif touch3.value:
    cpx.play_file("elec_cymbal.wav")
    time.sleep(BPM)
  elif touch4.value:
    cpx.play_file("elec_blip2.wav")
    time.sleep(BPM)
  elif touch5.value:
    cpx.play_file("bd_tek.wav")
    time.sleep(BPM)
  elif touch6.value:
    cpx.play_file("bass_hit_c.wav")
    time.sleep(BPM)
  elif touch7.value:
    cpx.play_file("drum_cowbell.wav")
    time.sleep(BPM)

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touch1 = None
touch2 = None
touch3 = None
touch4 = None
touch5 = None
touch6 = None
touch7 = None

BPM = None


import time
import board
import touchio
from digitalio import *
from adafruit_circuitplayground.express import cpx
BPM = .125
touch1 = touchio.TouchIn(board.A1)
touch2 = touchio.TouchIn(board.A2)
touch3 = touchio.TouchIn(board.A3)
touch4 = touchio.TouchIn(board.A4)
touch5 = touchio.TouchIn(board.A5)
touch6 = touchio.TouchIn(board.A6)
touch7 = touchio.TouchIn(board.A7)
while True:
  if touch1.value:
    cpx.play_file("bd_tek.wav")
    time.sleep(BPM)
  elif touch2.value:
    cpx.play_file("elec_hi_snare.wav")
    time.sleep(BPM)
  elif touch3.value:
    cpx.play_file("elec_cymbal.wav")
    time.sleep(BPM)
  elif touch4.value:
    cpx.play_file("elec_blip2.wav")
    time.sleep(BPM)
  elif touch5.value:
    cpx.play_file("bd_tek.wav")
    time.sleep(BPM)
  elif touch6.value:
    cpx.play_file("bass_hit_c.wav")
    time.sleep(BPM)
  elif touch7.value:
    cpx.play_file("drum_cowbell.wav")
    time.sleep(BPM)

If the code does not work when uploaded to the CPX, you may have to use a code editor and REPL to figure out what's going wrong.

This is a common process in programming known as "troubleshooting" or "debugging".

A code editor and REPL will help you determine which part of your code may be causing errors.

Follow directions on how to download a code editor and troubleshoot issues with the REPL here.

Going Further:

How can you modify the examples from this guide to make even cooler programs with EduBlocks and the CPX? 

One idea could be to trigger different NeoPixel colors when drum sounds are triggered!

The possibilities are endless!