The Mu Editor
Adafruit recommends using the free program Mu to edit your CircuitPython programs and save them on your Circuit Playground Bluefruit. You can use any text editor, but Mu has some handy features.
See this page on the Circuit Playground Bluefruit guide on the steps used to install Mu.
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.
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 CPB_Ornament_Proximity/ 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
# SPDX-FileCopyrightText: 2019 John Edgar Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT
"""
Circuit Playground Bluefruit Ornament Proximity
This demo uses advertising to set the color of scanning devices depending on the strongest broadcast
signal received. Circuit Playgrounds can be switched between advertising and scanning using the
slide switch. The buttons change the color when advertising.
"""
import time
from adafruit_circuitplayground.bluefruit import cpb
from adafruit_ble import BLERadio
from adafruit_ble.advertising.adafruit import AdafruitColor
# The color pickers will cycle through this list with buttons A and B.
color_options = [0x110000,
0x111100,
0x001100,
0x001111,
0x000011,
0x110011,
0x111111,
0x221111,
0x112211,
0x111122]
ble = BLERadio()
i = 0
advertisement = AdafruitColor()
advertisement.color = color_options[i]
cpb.pixels.auto_write = False
cpb.pixels.fill(color_options[i])
while True:
# The first mode is the color selector which broadcasts it's current color to other devices.
if cpb.switch:
print("Broadcasting color")
ble.start_advertising(advertisement)
while cpb.switch:
last_i = i
if cpb.button_a:
i += 1
if cpb.button_b:
i -= 1
i %= len(color_options)
if last_i != i:
color = color_options[i]
cpb.pixels.fill(color)
cpb.pixels.show()
print("New color {:06x}".format(color))
advertisement.color = color
ble.stop_advertising()
ble.start_advertising(advertisement)
time.sleep(0.5)
ble.stop_advertising()
# The second mode listens for color broadcasts and shows the color of the strongest signal.
else:
closest = None
closest_rssi = -80
closest_last_time = 0
print("Scanning for colors")
while not cpb.switch:
for entry in ble.start_scan(AdafruitColor, minimum_rssi=-100, timeout=1):
if cpb.switch:
break
now = time.monotonic()
new = False
if entry.address == closest:
pass
elif entry.rssi > closest_rssi or now - closest_last_time > 0.4:
closest = entry.address
else:
continue
closest_rssi = entry.rssi
closest_last_time = now
discrete_strength = min((100 + entry.rssi) // 5, 10)
cpb.pixels.fill(0x000000)
for i in range(0, discrete_strength):
cpb.pixels[i] = entry.color
cpb.pixels.show()
# Clear the pixels if we haven't heard from anything recently.
now = time.monotonic()
if now - closest_last_time > 1:
cpb.pixels.fill(0x000000)
cpb.pixels.show()
ble.stop_scan()
import time from adafruit_circuitplayground.bluefruit import cpb from adafruit_ble import BLERadio from adafruit_ble.advertising.adafruit import AdafruitColor
We'll be able to call on Circuit Playground Bluefruit board functions with the cpb command, including simplified ways to access the buttons and switch, as well as the on board red LED and the NeoPixels.
We're also setting up the Bluetooth LE radio and the package needed to advertise color values.
Color List
Next, we create a list of color values (in hex):
# The color pickers will cycle through this list with buttons A and B.
color_options = [0x110000,
0x111100,
0x001100,
0x001111,
0x000011,
0x110011,
0x111111,
0x221111,
0x112211,
0x111122]
Bluetooth and NeoPixel Setup
The BLE radio is instantiated next, as well as the AdafruitColor() object to advertise the color value of the board.
Also, we'll use the cpb.pixels.auto_write command to set the pixel auto write to False this helps avoid flickering NeoPixels (thanks Roy!) and the NeoPixel fill color.
ble = BLERadio() i = 0 advertisement = AdafruitColor() advertisement.color = color_options[i] cpb.pixels.auto_write = False cpb.pixels.fill(color_options[i])
Main Loop
The main loop of the code happens in the while True: section.
Switch Left to Broadcast
Here, we check the position of the switch by asking if cpb.switch: and if it is True, this means the switch is positioned to the left and the board will be in broadcast mode (the "hidden" ornaments are going to be the ones in broadcast mode).
Then, button presses are used to increment or decrement through the color list, and set the NeoPixels to that color.
Every half second, the board will advertise this color information over Bluetooth with the ble.start_advertising(advertisement) command.
if cpb.switch:
print("Broadcasting color")
ble.start_advertising(advertisement)
while cpb.switch:
last_i = i
if cpb.button_a:
i += 1
if cpb.button_b:
i -= 1
i %= len(color_options)
if last_i != i:
color = color_options[i]
cpb.pixels.fill(color)
cpb.pixels.show()
print("New color {:06x}".format(color))
advertisement.color = color
ble.stop_advertising()
ble.start_advertising(advertisement)
time.sleep(0.5)
ble.stop_advertising()
Switch Right to Detect
In the case that the cpb.switch value is False (in the code, not True), this means it's flipped to the right and the board will be in listening/detect mode.
Now, we'll used the Bluetooth LE radio to scan the airwaves and use its received signal strength indicator (RSSI) capability to single out the board with the strongest signal.
The color entry being broadcast by the strongest (usually nearest) board is used in setting the NeoPixel color, while the number of pixels being lit is based on the signal strength.
else:
closest = None
closest_rssi = -80
closest_last_time = 0
print("Scanning for colors")
while not cpb.switch:
for entry in ble.start_scan(AdafruitColor, minimum_rssi=-100, timeout=1):
if cpb.switch:
break
now = time.monotonic()
new = False
if entry.address == closest:
pass
elif entry.rssi > closest_rssi or now - closest_last_time > 0.4:
closest = entry.address
else:
continue
closest_rssi = entry.rssi
closest_last_time = now
discrete_strength = min((100 + entry.rssi) // 5, 10)
cpb.pixels.fill(0x000000)
for i in range(0, discrete_strength):
cpb.pixels[i] = entry.color
cpb.pixels.show()
# Clear the pixels if we haven't heard from anything recently.
now = time.monotonic()
if now - closest_last_time > 1:
cpb.pixels.fill(0x000000)
cpb.pixels.show()
ble.stop_scan()
Next, we'll put together the ornaments and use them in a scavenger hunt!
