Robot Club

Halloween Tutorial 1

We are using the Itsy Bitsy M0 Express from Adafruit.

Mu ("Moo") is a nice IDE used to edit the code and debug.

• First, plug the board in a open Mu. Load main.py from the CIRCUITPY drive. Open the serial monitor.
• Second, go into REPL mode and communicate with the board. Practice entering (CTRL-c) and exiting (CTRL-D) REPL.
• Third, make a local copy of main.py, in case you ever want to see the original examples again.
• Forth, replace the contents of main.py with:

import board # pin definitions import time # time functions import touchio # capacitivectouch library import pulseio # pwm library import adafruit_dotstar # dotstar rgb led library

1. One dotstar soldered on the board

dot = adafruit_dotstar.DotStar(board.APA102_SCK, board.APA102_MOSI, 1, brightness=0.2)

1. Built in red LED

led = pulseio.PWMOut(board.D13, frequency=5000, duty_cycle=0) led.duty_cycle = 0 # initially off

1. Capacitive touch on A2

touch = touchio.TouchIn(board.A2)

1. Helper to give us a nice color swirl

def wheel(pos):

   # Input a value 0 to 255 to get a color value.
   # The colours are a transition r - g - b - back to r.
   if (pos < 0):
       return [0, 0, 0]
   if (pos > 255):
       return [0, 0, 0]
   if (pos < 85):
       return [int(pos * 3), int(255 - (pos*3)), 0]
   elif (pos < 170):
       pos -= 85
       return [int(255 - pos*3), 0, int(pos*3)]
   else:
       pos -= 170
       return [0, int(pos*3), int(255 - pos*3)]

1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. MAIN LOOP ##############################

i = 0 # a variable to keep track of time while True:

   time.sleep(.01) # wait 0.01 seconds. if this isn't here the code might run too fast
   i = (i+1) % 256  # run from 0 to 255
   dot[0] = wheel(i & 255) # set the color of the dotstar, [red green blue]
   led.duty_cycle = i*255 # duty_cycle can be 0 to 65535
   if i%100==0: # if i is divisible by 100
       # printing at this slow speed because sending too often chokes the computer
       print("A2 touch: %d" % touch.raw_value, end="\n") # print the value of the cap touch sensor on pin A2