Tuesday, September 27, 2016

Adafruit Circuit Playground Second Hour

If you have followed last week's post on Adafruit's Circuit Playground, you now have a working communication between your computer and the board. In this example, I would like to establish the communication between my Raspberry Pi over the serial communication to the board. This way I can leverage everything the RasPi has while utilizing the sensors and outputs from the board. 

The package I need is PySerial, which can be installed via 'sudo pip install pyserial'. It is used as the 'serial' package in Python code. 

Here is the objective: 
  1. The Arduino code will print out serial output when either the right or left button is pressed.
  2. When the B key is pressed, the LED light will light up one at a time. 
  3. In the Python code we will send the letter B 9 times then wait for any serial input

Here is the Python code. Python Code. A few notes: 

- Raspberry Pi the serial port is /dev/ttyACM0 and /dev/cu.usbmodem142 on Mac, therefore I comment out the line depending on if I am on the Mac or Raspberry Pi. 
- The character is sent as Bytecode, so chr(0x42) is used for letter 'B'. Here is an ASCII table. 

- Timeout of 1 second is used to gradually light up the LED. 

import serial
import time

#ser = serial.Serial('/dev/ttyACM0', 9600)
ser = serial.Serial('/dev/cu.usbmodem1421', 9600)

# ASCII character 'B'
sendChr = chr(0x42)

# Send character B which turns on light one at a time
for i in range(9):

# Read the input from board
while True:
    message = ser.readline()

Here is the Arduino Code: 

- I am using the Demo code provided by Adafruit:

- Use the library manager to install the Adafruit Circuit Playground Libraries

// Demo program for testing library and board - flip the switch to turn on/off buzzer

#include <Adafruit_CircuitPlayground.h>
#include <Wire.h>
#include <SPI.h>

// we light one pixel at a time, this is our counter
uint8_t pixeln = 0;

byte byteRead;

void setup() {
  //while (!Serial);
  Serial.println("Circuit Playground test!");


void loop() {

  /************* TEST BOTH BUTTONS */
  if (CircuitPlayground.leftButton()) {
    Serial.println("Left button pressed!");
  if (CircuitPlayground.rightButton()) {
    Serial.println("Right button pressed!");

  /************** Read Serial In, 65 DEC ASCII is letter B */
  byteRead = Serial.read();
  if(byteRead == 66) {
    Serial.println("Letter B input, turn on light");
    CircuitPlayground.setPixelColor(pixeln++, CircuitPlayground.colorWheel(25 * pixeln));
    if (pixeln == 11) {
    pixeln = 0;

Another screenshot for the IDE: 

You can also use the serial monitor included with the Arduino IDE to test: 

This is really fun, I cant wait to see all the possibilities when combining the two! 

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