RF wall switch

[roadversion]

I need a wall switch to communicate with RF signal to my Arduino, but I don't need to spend $100 to also get some sort of receiver, such as a controlled outlet.  Just the switch to transmit the signal, and looking like a regular wall switch, like this one:
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http://www.goodmart.com/images/prodimages/lutron/ClaroWhiteSwitch.jpg
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     Any ideas?   Thanks in advance.

[Dmitron1036]

bluetooth (Bluetooth Data Link Board Module for Pixhawk Flight Controller Works with ...)
or NRF24L01 Wireless Transmission Module w/ Antenna - Green....
or wifi switch + ethernet card

[sid1202]

Check this out

https://lowpowerlab.com/shop/product/110

[ElCaron]

https://www.openhardware.io/view/13/In-Wall-ACDC-Pcb-for-MySensors

[esogold]

good

[mauried]

One of the problems with simple light switches is that the switch simply opens and closes the active line to the light, so its not possible to power anything when the switch is on.
The commercial type light switches with a receiver / transmitter inside need a neutral line as well to power the additional electronics, and the neutral line is quite often missing.