Kernel hacking for the RFM12B

RFM12BI’ve been busying myself with fixing up and adapting the RFM12B Linux driver. My first thought was simply to give people support for sending and listening for OOK signals as an extension, then taking the device support in the rtl_433 decoder to extend RFM12B driver to include lots of OOK device support for things like weather stations and energy monitors.

JeeLib already does most of this work on Arduino so for the most part this is simply a matter of joining lots and lots of code together from different places and making sure it sits right. I’ve decided that in order to do this it would probably be better to re-write the driver while trying to fix some of the original driver’s TODO list along the way.

The driver will loosely allow :-

  • Compatibility with the original RFM12B driver & original JeeLib compatibility.
  • Send OOK, FSK messages to devices.
  • Listen for OOK, FSK messages from devices.
  • Set tuning to a specific frequency.

Continue reading →

RFM12B-Linux and OOK/ASK and Oregon Scientific v3 protocol

RFM12BThe Owl energy monitor uses OOK/ASK via the Oregon Scientific v3 protocol. It looks like I might have to hardware hack my RFM12Bs to work with this protocol according to this article… Not ideal.

Receiving OOKASK with a modified RFM12B – JeeLabs Café – JeeLabs . net.

Although it seems there’s a branch of RFM12B-Linux which can do OOK already. I’m not entirely sure how this is going to work out, but I’ll keep posting.

I found some problems with RFM12B Linux, specifically it doesn’t work at all on the Raspberry Pi B+ 2. I’ve created an issue for this but I might be able to fix it if I can get some tinkering time. In the mean time I’m testing things with the original model B.

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OWL CM160 Energy Monitor with RTL-SDR

OWL CM160I have an Owl energy monitor model CM160, which has been mostly just acting as a real time monitor. In order to really USE the device I’m going to need to connect it to one of my running computers. At first I was using Eagle OWL on github. However it requires me keeping the LCD receiver and I want to eventually get rid of that, mostly because the only useful thing about it, the thermometer isn’t accessible over USB.

I decided that I should start experimenting around the 434MHz band with my SDR’s and see what I could come up with. Continue reading →