Computing stuff tied to the physical world


In AVR on Dec 20, 2008 at 15:56

Failures are worth documenting too… here is one:


This was intended to become a general-purpose 868 MHz wireless solution: a low-end receiver + transmitter from Conrad, alongside an 868 MHz RFM12B which is likely to become my workhorse module. The receiver + transmitter are compatible with the FS20 wireless remote protocol, and allow listening as well as controlling these devices.

Well, most of this stuff didn’t work once hooked up. For various reasons actually – from bad sensitivity to using the wrong module (turns out that RFM12 unit was in fact for 433 MHz, doh).

In an attempt to salvage this thingamagic, I decided to replace & rewire the whole thing. It is now a 433 MHz receiver + transmitter, and an RFM12, also working on 433 MHz. The whole has been put aside for now, but maybe one day it can be made to work with some 433 MHz stuff, such as this or some cheap weather sensors.

Due to the switch to a lower frequency band, all three antennas are now 17 cm long wires.

The microcntroller is an Arduino Nano, btw. This is a 16 MHz 5V unit with a mini-USB port.