rs232-rf

Sending RF Using a PC Serial Port

RF transmitters need less than 10mA so this design steals power from the RTS line. The DTR line is toggled to form the data pulsetrain. The transmitter shown is a 4-pin module from Wenshing. There are similar modules available from several sources.

Sending RF Using a USB-Serial Adapter

For PCs without RS-232 ports, the same thing can be done using USB-serial adapters like the breakout boards sold by SFE. In these cases you can power the transmitter from the USB bus.

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