110 lines
3.8 KiB
Python
110 lines
3.8 KiB
Python
# SPDX-FileCopyrightText: Copyright (c) 2021 Eva Herrada for Adafruit Industries
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# SPDX-FileCopyrightText: Copyright (c) 2021 Dan Halbert for Adafruit Industries
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#
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# SPDX-License-Identifier: Unlicense
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"""
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Code for communicating between two CircuitPlayground Express boards using UART.
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Sends value from the onboard light sensor to the other board and the other board sets its
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NeoPixels accordingly.
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"""
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import time
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import board
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import busio
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import digitalio
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import neopixel
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import analogio
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pixels = neopixel.NeoPixel(board.NEOPIXEL, 10, brightness=0.1, auto_write=False)
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light_sensor = analogio.AnalogIn(board.LIGHT)
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btn_A = digitalio.DigitalInOut(board.BUTTON_A)
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btn_A.switch_to_input(pull=digitalio.Pull.DOWN)
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btn_B = digitalio.DigitalInOut(board.BUTTON_B)
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btn_B.switch_to_input(pull=digitalio.Pull.DOWN)
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# Use a timeout of zero so we don't delay while waiting for a message.
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uart = busio.UART(board.TX, board.RX, baudrate=9600, timeout=0)
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# Messages are of the form:
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# "<TYPE,value,value,value,...>"
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# We send and receive two types of messages:
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#
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# Message contains a light sensor value (float):
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# <L,light>
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#
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# Message contains statuses of two buttons. Increment NeoPixel brightness by 0.1 if the second
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# button is pressed, and reduce brightness by 0.1 if the first button is pressed.
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# <B,btn_A,btn_B>
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UPDATE_INTERVAL = 3.0
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last_time_sent = 0
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# Wait for the beginning of a message.
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message_started = False
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while True:
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# Send light sensor value only every UPDATE_INTERVAL seconds.
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now = time.monotonic()
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if now - last_time_sent >= UPDATE_INTERVAL:
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light = light_sensor.value
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uart.write(bytes(f"<L,{light}>", "ascii"))
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print("sending light value", light)
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last_time_sent = now
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if any((btn_A.value, btn_B.value)):
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# Send values of built-in buttons if any are pressed
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uart.write(bytes(f"<B,{btn_A.value},{btn_B.value}>", "ascii"))
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print(f"Sent ({btn_A.value}, {btn_B.value})")
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# Don't do anything else until both buttons are released
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time.sleep(0.1)
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while any((btn_A.value, btn_B.value)):
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pass
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byte_read = uart.read(1) # Read one byte over UART lines
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if byte_read is None:
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# Nothing read.
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continue
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if byte_read == b"<":
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# Start of message. Start accumulating bytes, but don't record the "<".
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message = []
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message_started = True
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continue
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if message_started:
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if byte_read == b">":
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# End of message. Don't record the ">".
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# Now we have a complete message. Convert it to a string, and split it up.
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print(message)
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message_parts = "".join(message).split(",")
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message_type = message_parts[0]
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message_started = False
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if message_parts[0] == "L":
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# Received a message telling us a light sensor value
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peak = int(((int(message_parts[1]) - 2000) / 62000) * 10)
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for i in range(0, 10):
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if i <= peak:
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pixels[i] = (0, 255, 0)
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else:
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pixels[i] = (0, 0, 0)
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pixels.show()
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print(f"Received light value of {message_parts[1]}")
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print(f"Lighting up {peak + 1} NeoPixels")
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elif message_parts[0] == "B":
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# Received a message asking us to change our brightness.
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if message_parts[1] == "True":
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pixels.brightness = max(0.0, pixels.brightness - 0.1)
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print(f"Brightness set to: {pixels.brightness}")
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if message_parts[2] == "True":
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pixels.brightness = min(1.0, pixels.brightness + 0.1)
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print(f"Brightness set to: {pixels.brightness}")
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else:
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# Accumulate message byte.
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message.append(chr(byte_read[0]))
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