Martin's corner on the web

Interfacing RFM12B to Raspberry Pi for cheap

I managed to interface one of my TinySensors to my Raspberry Pi via Pi’s UART. The idea is to use it to receive RFM12b transmissions and re-transmit on Pi’s UART where a serial gateway will pick the data and post to emoncms. I only need one-way transmission i.e. from the TinySensor to the Pi. Edit: [Two way serial is now available]

It was pretty straight forward task, here are some details:

  1. I had to make sure that Pi’s UART is detached from the kernel’s serial console by following @argilo’s instructions posted here 
  2. I installed minicom on tje Raspberry Pi so that I will be able to see the output
  3. I wrote a small sketch that will intercept RFM12b messages from  the Arduino with SensorShield on my electricity meter and forward those to Pi’s UART. Note that the Arduino Tiny Core does support software serial output, so it worked right away

Here are some pictures from the test run

I also have emoncms installed and running on my Pi, so all that remains is to make a small script to catch serial input and make a post to emoncms..

I am quite happy so far, this is going to be a really cheap solution because the TinySensor is really made up of quite a few inexpensive components.



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