Laser module transmission script

main.py

import RPi.GPIO as GPIO
import time, random
import os, subprocess
from threading import Thread
GPIO.setmode(GPIO.BOARD)
GPIO.setwarnings(False)
import sys,tty,os,termios
from keypresses import getkey


GPIO.setup(8,GPIO.OUT)
GPIO.setup(40, GPIO.OUT)
GPIO.output(40, GPIO.HIGH)
GPIO.output(8, GPIO.LOW)
GPIO.setup(10, GPIO.IN)

send_speed = 0.001
send_speed_mid = send_speed/2

def begin_listener(expecting_bits):
    global end_string
    time.sleep(send_speed_mid)
    bits = ""
    while True:
        read_bit = GPIO.input(10)
        bits += str(read_bit)
        if len(bits) == expecting_bits:
            break
        time.sleep(send_speed)
    key = chr(int(bits, 2))
    end_string += key


def send_data(list_of_bits):
    GPIO.output(8, GPIO.HIGH)
    timer = 0
    print("connect laser and transmitter to begin ...")
    while True:
        time.sleep(0.001)
        if not (GPIO.input(10)):
            timer += 1
        else:
            timer = 0
        if timer > 1000:
            break
    print("sending ...")
    GPIO.output(8, GPIO.LOW)
    oldtime = time.time()
    for bits in list_of_bits:
        GPIO.output(8, GPIO.LOW)
        Thread(target=begin_listener, args=(len(bits),)).start()
        for bit in bits:
            GPIO.output(8, [GPIO.HIGH, GPIO.LOW][int(bit)])
            time.sleep(send_speed)
        time.sleep(send_speed)
    print("complete!")
    print("transmission took {0:.{1}f} seconds.".format(time.time() - oldtime, 4))
    GPIO.output(8, GPIO.LOW)

end_string = ""
with open("new.txt", "r") as f:
    string = f.read()
data = []

for character in string:
    data.append(''.join(format(x, 'b') for x in bytearray(character, 'utf-8')))
print("preparing to send file 'new.txt' of size {}kB...".format(os.path.getsize("new.txt")/1000))
send_data(data)

if not(string == end_string):
    print("errors detected.")