Receiving signals from other 433Mhz devices

Kevin SkyMoCo

Is is possible to read other devices (specifically an Oregon Scientific wind speed sensor)
which transmits on 433Mhz using a stamp and the 433Mhz receiver? I have a number of
nifty sensors that came with a now broken base unit.

I doubt anybody has done it, but it is possible in theory? How would one go about it?

Steel

Yeah, anything that is being transmitted on 433M can be recieved on 433M...But you need to have the right information to read it.

There are a couple things you need to keep in mind:

Speed:· You won't be able to just hook up your controller to read.· You will need to find out what speed the data is being sent at.· The best tool to use this is an Oscilloscope.· This way you can set your controller to read at that speed.

Levels: make sure that the data level is strong enough to be read by your controller.

Protocol:· Most wireless devices use a standard communication protocol.· For example, When I create a wireless device I generally use the following structure:· Start Byte|Total number of Packets|Packet Number|Data/Status Header|Data/Status|Checksum|End Byte

That is a simple protocol.· Most products *should* have much more complex than that.

Once you have the right speed and levels, you will be able to recieve the information, but you will also have to break down their protocol...that is much more complex...especially if they use any scrambling algorithms.






Post Edited (Steel) : 5/31/2006 8:25:10 PM GMT

Paul Baker

Actually it's not quite as simple as having two devices on the same frequency, and getting the right protocol. The devices must also communicate using the same type of modulation of which the are many types (AM,FM,OOK,PSK,QPSK,...), you would likely need to write to Oregon Scientific asking what type of modulation thier devices use and what the protocol is. If you can at least get them to state which modulation they use, and get a compatible receiver, you can possibly reverse engineer the protocol with some perserverence.

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Kevin SkyMoCo

Thanks, I'll write to them and see what they say. I don't expect a reply, but you never know...

lockburn

I'd like to see if it would be possible to read from these devices if a controller was directly wired to it (not wireless).

For example, I have a bunch of Oregon Scientific temperature/humidity sensors with small LCD's. I thought it would be nice to wire one into each room to remotely monitor environmental conditions. By going wireless, you're limited to 3 devices. But, I thought by going the wired route, I could link up every room in the house, provide power (3v) over the same lines, and later down the line make this an advanced hvac controller.

Anyone try anything similar yet?