A minimal rfcat replay script for a garage door opener

replay.py

#!/usr/bin/python
import rflib
import bitstring

rfcat = rflib.RfCat()
rfcat.setFreq(314850000)

# AM On/Off Keying
rfcat.setMdmModulation(rflib.MOD_ASK_OOK)

# in audacity, out biggest pulse is about 
# 20 samples wide in a 440000 Hz wavefile
pulse_width = 20.0
sample_rate = 44000.0

# set the baudrate
rfcat.setMdmDRate(1.0/(pulse_width/sample_rate))

# easier to just use ASCII for now, then convert to bytes later
data = '01010101010101011100000000000000'
clocked_data = ''.join(['1110' if b == '1' else '1000' for b in data])

# there is a preamble before the data
clock_data_with_preamble = '00000000%s' % clocked_data

# convert our binary ASCII string to bytes
packet = bitstring.BitArray(bin=clock_data_with_preamble).tobytes()

# not actually sure why the repeat parameter is necessary ...
rfcat.RFxmit(packet, repeat=1)