Wifi Radar

[tobol.7uno]

I want to hack a wifi router somehow so that I can reprogram it to act as a radar. Emitting a signal for a microsecond and listening for returns and measuring their intensity. I dont know if the hardware in a router is fast enough for this or if it is possible to find an API or something to reprogram the router. Also not sure if this is the right category for this.

 

[RadioRon]

I think that router hardware is going to be too slow for such an idea. While getting a very short pulse out may be possible, I don't think that you can turn around (go from transmit to receive) quickly enough to be ready to receive the return pulse over a short range. Longer ranges may be OK. A more practical problem that you will come up against is that the existing API probably does not give you visibility of the underlying hardware at the level you need to play around with all the functions. Another practical problem is that the chips inside routers are highly integrated and the guts of the chips are not publicized. You would have to get friendly with someone at, say, Atheros, to get access to the insider information that you need. Such chipsets often have diagnostic portals that allow the factory or R&D department to play around with the hardware, perhaps you could discover this interface.

 

[LTX71CM]

... I don't think that you can turn around (go from transmit to receive) quickly enough to be ready to receive the return pulse over a short range. Longer ranges may be OK.

I don't think that will be a problem, routers like the wrt54g have dual transceivers so data can be sent and received simultaneously. I would have assumed one side was transmit and one was receive but when using custom firmware like DD-Wrt you can alter which antenna does what, and also adjust the power level.

A wrt54g might be your best option, you can download the source code straight from Linksys and modify it as necessary. A few words of caution, make sure you buy the right revision of the 54g, some run on VXworks and that code is not open.

 

[lutful]

Atheros is the most prominent WiFi transceiver maker now and provides GPL driver code - Google for ath9k and browse the "HAL" or hardware access layer.

However ... I have worked extensively with various WiFi transceivers (Intersil, Agere, Atheros) since 2003 and I can assure you that they are not capable of "classic" radar type functionality with any amount of software programming. Sorry about that.

Short pulse generation and reception could be done with various ISM band components, but I think only an FPGA would be fast enough to do the "time of flight" measurement.

P.S. I just joined the forum.