75 lines
2.8 KiB
Python
75 lines
2.8 KiB
Python
# SPDX-FileCopyrightText: 2023 Pete Warden
|
|
# SPDX-License-Identifier: Apache-2.0
|
|
#
|
|
# Example of accessing the Tiny Code Reader from Useful Sensors on a Trinkey
|
|
# using CircuitPython. See https://usfl.ink/tcr_dev for the full developer guide.
|
|
|
|
import struct
|
|
import time
|
|
import board
|
|
import usb_hid
|
|
|
|
from adafruit_hid.keyboard import Keyboard
|
|
from adafruit_hid.keyboard_layout_us import KeyboardLayoutUS
|
|
|
|
# The code reader has the I2C ID of hex 0c, or decimal 12.
|
|
TINY_CODE_READER_I2C_ADDRESS = 0x0C
|
|
|
|
# How long to pause between sensor polls.
|
|
TINY_CODE_READER_DELAY = 0.2
|
|
|
|
TINY_CODE_READER_LENGTH_OFFSET = 0
|
|
TINY_CODE_READER_LENGTH_FORMAT = "H"
|
|
TINY_CODE_READER_MESSAGE_OFFSET = TINY_CODE_READER_LENGTH_OFFSET +
|
|
struct.calcsize(TINY_CODE_READER_LENGTH_FORMAT)
|
|
TINY_CODE_READER_MESSAGE_SIZE = 254
|
|
TINY_CODE_READER_MESSAGE_FORMAT = "B" * TINY_CODE_READER_MESSAGE_SIZE
|
|
TINY_CODE_READER_I2C_FORMAT = TINY_CODE_READER_LENGTH_FORMAT + TINY_CODE_READER_MESSAGE_FORMAT
|
|
TINY_CODE_READER_I2C_BYTE_COUNT = struct.calcsize(TINY_CODE_READER_I2C_FORMAT)
|
|
|
|
i2c = board.I2C()
|
|
|
|
# Wait until we can access the bus.
|
|
while not i2c.try_lock():
|
|
pass
|
|
|
|
# For debugging purposes print out the peripheral addresses on the I2C bus.
|
|
# 98 (0x62 in hex) is the address of our person sensor, and should be
|
|
# present in the list. Uncomment the following three lines if you want to see
|
|
# what I2C addresses are found.
|
|
# while True:
|
|
# print(i2c.scan())
|
|
# time.sleep(TINY_CODE_READER_DELAY)
|
|
|
|
# Create a keyboard device so we can send the screen lock command.
|
|
keyboard = Keyboard(usb_hid.devices)
|
|
layout = KeyboardLayoutUS(keyboard)
|
|
|
|
last_message_string = None
|
|
last_code_time = 0.0
|
|
|
|
while True:
|
|
read_data = bytearray(TINY_CODE_READER_I2C_BYTE_COUNT)
|
|
i2c.readfrom_into(TINY_CODE_READER_I2C_ADDRESS, read_data)
|
|
|
|
message_length, = struct.unpack_from(TINY_CODE_READER_LENGTH_FORMAT, read_data,
|
|
TINY_CODE_READER_LENGTH_OFFSET)
|
|
message_bytes = struct.unpack_from(TINY_CODE_READER_MESSAGE_FORMAT, read_data,
|
|
TINY_CODE_READER_MESSAGE_OFFSET)
|
|
|
|
if message_length > 0:
|
|
message_string = bytearray(message_bytes)[0:message_length].decode("utf-8")
|
|
is_same = (message_string == last_message_string)
|
|
last_message_string = message_string
|
|
current_time = time.monotonic()
|
|
time_since_last_code = current_time - last_code_time
|
|
last_code_time = current_time
|
|
# Debounce the input by making sure there's been a gap in time since we
|
|
# last saw this code.
|
|
if (not is_same) or (time_since_last_code > 1.0):
|
|
print(message_string)
|
|
try:
|
|
layout.write(message_string)
|
|
except ValueError as e:
|
|
pass
|
|
layout.write("\n")
|