#! /usr/bin/python3
# encoding: utf-8

import serial
import struct

# ----------------------------------------------------------------
# Config

BAUD_RATE = 9600
PORT = "/dev/ttyACM0"
KWH_PER_IMPULSE = 0.1 # 100 Wh/imp

# ----------------------------------------------------------------

if __name__ == "__main__":
	serial.Serial() as s:
		s.baudrate = BAUD_RATE
		s.port = PORT
		s.timeout = None # wait forever
		s.open()

		while True:
			# expecting the pulse count as a big endian (AVR) uint32_t
			raw = s.read(4) # e.g. b"@\xe2\x01\x00" (hex 40 e2 01 00)
			count = struct.unpack("<I", raw) # e.g. 123456
			energy = count * KWH_PER_IMPULSE # e.g. 12345.6 kWh

			print("counter=%i imp, energy=%.01f kWh" %(count, energy))