I have an emonpi (Raspberry Pi 3) with the bundled temperature sensor that I purchased in March 2018 and would now like to monitor my gas usage. I think I know how to do this but would welcome any advice or comments on my plan.
I have a Schlumberger R5 gas meter which has an RJ11 socket that gives out a pulse (probably a reed switch) on pins 3 & 4 for each cubic foot of gas used. I have tested this by connecting a cable from the meter to the GPIO on another Raspberry Pi 3 and using a python script, primarily to debounce the pulse and record the pulse count. The recorded pulse count plus the meter reading when the script started matches the new meter reading.
My plan is to connect the cable from the meter to the GPIO on the emonpi Raspberry Pi with the debounce script running and this script would also output a signal from a GPIO pin that I would feed to the digital pin 3 on the emonpi ATmega328 board.