Computing stuff tied to the physical world

Light to RF converter

In Hardware on Oct 8, 2009 at 00:01

While testing out some new code to handle extended FS20 packets in the forum, I remembered that I had an FS20 LS sensor still lying around:


Puzzled? Maybe the back will show a bit better what this thing is about:


Still puzzled? Me too – until I assembled the kit and tried it out. There is a light sensor on the back with a bit of sticky tape, which you’re supposed to place over a LED or some other light signal.

What it does is whenever light on or off is detected, it sends out an RF signal at 868 MHz using the FS20 protocol. So any FS20 receiver can pick it up:

Picture 3.png

The four buttons are a way to adjust all sorts of settings. I haven’t tried those, the factory defaults seem to work just fine for me. As it is this is a nice install-and-forget unit. Hopefully the battery will last a year or more.

Could this report the fridge light? Hmm, not sure – not all packets are coming out. Maybe it’ll be ok if the receiver is close enough.

Cool – another wireless gadget to help automate stuff around the house!

  1. This little thing looks like a perfect companion for a remote power meter. Some electricity meters blink in a rate dependant of the power consumption. I think mine does too…

    • I’m not sure this would work though – while trying it out, I got the impression that this unit only responds to relatively slow-changing light signals – several seconds of dead-time after triggering. The other thing to watch out for is lost packets, which will affect measurement accuracy. That’s why I use a JeeNode right next to the meter, and pass on the total counts.

Comments are closed.