autobrightness

import serial
import os
import time
import math


#requires - pip install pyserial
# and ddcutil

#this reads the arduino serial device from a serial port
#and converts it to a luminosity value through a function like y=mx+b
#where i just checked my prefered brightgness value and the luminosity of the room when my its darkest and when its brigetest
#so i got something like (aproximating from memory) 4 monitor brightess at 35 lumens room brightness,
#and 28 monitor brightess at 400 lumens room brightness
#this got me to y=0.052*x+ 4.725 5 is the minimum brightness value and the code caps the max brightness at 26



current_milli_time = lambda: int(round(time.time() * 1000))

#realine() from the serial api was giving garbled/inconsistent output, so im using this instead
#to parse the messages from the serial device
def readln(srl):
    srl.reset_input_buffer()
    foundN = False
    foundR = False
    char = ''
    outs = list()
    while not(foundN and foundR) :
        char = str(srl.read())
        #print(char[3])
        if(foundN or char[3] == 'n'):
            #print(char[3])
            outs.append(char[2])
            foundN = True
            if (char[3] == 'r'):
                foundR = True

    del outs[0]
    del outs[len(outs) - 1]
    #print(''.join(outs))
    return ''.join(outs)


ser = serial.Serial('/dev/ttyACM0')

print("connected to: " + ser.portstr)


currentX = 0
adjCount = 1000
while True:
    #ltime = int(current_milli_time())
    #read luminosity
    line = float(readln(ser))
    #print(line)
    #compute brighness
    x = round((0.052 * line) + 4.725)
    #clamp it to 26
    if x > 26 : x = 26
    #print(x)
    #if there is no significant change skip sending commands to the monitor
    if x != currentX:
        os.system("ddcutil -d 1 setvcp 10 %u" % x)
        adjCount += 1
        print(x)
        #print the incremental number of changes just so that i can check that it isnt borked
        print(adjCount)
        #print(current_milli_time())
        currentX = x
    #ctime = int(current_milli_time())
    #print (ctime - ltime)


ser.close()