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--- modnexaremote [2009/06/15 22:09] – created sestst
+++ modnexaremote [2009/06/29 22:52] – sestst
@@ Line 1: / Line 1: @@
+{{ :nexatotal.jpg |Nexa Receiver and Transmitter}}
 ====== Generic 433 MHz transmitter ======
 The [[audioprotocoltransmitter | AudioProtocolTransmitter]] module, can encode digital protocols as audio signals from the sound card/audio output from a PC. To be able to transmit the signals, some kind of hardware is needed. This is a description of how to build a generic RF-transmitter working on the 433MHz band.
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 ==== Locate the data output ====
 Locate the signal output pin from the chip. This is where the digital protocol is sent to the RF-transmitter stage.
 {{ :nexaremote1.jpg | Output pin}}
 ==== Disconnect the output pin ====
 Cut the track on the board from the output pin and the pin next to it, remove the surface mounted capacitor. This is a bit tricky, because the tracks are small...
 {{ :nexaremote2.jpg | Disconnect output pin}}
+==== Connect our signal ====
+The final step is to connect our digital output signal (from the OP-Amp) to the RF-transmitter. I used the hole in the PCB as guide and soldered it to the connecting pad of capacitor I removed:
+{{ :nexaremote3.jpg | Connect our signal to the transmitter}}
+Now any output from the sound card will be transmitted as a 433MHz signal, and we have a generic remote control transmitter!
+===== Step 3, Package =====
+There are many ways to hook this up to the computer. I used a cheap USB-headset converter as sound card, put the OP-Amp-circuit on a Veroboard and powered it from the USB-cable and finally put the whole pile into the box of an old WLAN-HUB. It looks ugly inside, but once I close the box I have a nice looking USB-connected generic 433MHz transmitter :-).
+{{ :nexaremote4.jpg | Ready transmitter}}
+The circuit board to the right of the Veroboard is actually a receiver I tried to put in the same box. I had to give that up, since it is to sensitive to the electromagnetic noise from the USB. I had to use the [[modupm|UPM-recevier]] connected via a fem meter cable to get away from the noise.