Simple RF Transmit and Receive

[dhouston]

If you are connecting the receiver CD pin (pin 3) directly to PORTD.2, CD may not go high enough to be seen as HIGH by PORTD.2. That's why the transistor is needed and why you need to monitor /CD (refer to p6 of the PDF specs for the receiver).

Look at the code I referenced earlier in Code Examples for how to encode/transmit and receive/decode a pulse train. It's all you need for this application. It sends two bytes. Both bytes are followed by their complement so some basic error detection is built in. One can be an ID and the other indicate motion or all clear. All clear is sent when motion is followed by a period with no motion plus every hour or so to indicate "all's well".

[koossa]

Dave, I will implement your code, thank you!

Will it be possible for me to connect the Receiver's RF In Pin to the PC's Comm Port?

Thx!!

[dhouston]

Will it be possible for me to connect the Receiver's RF In Pin to the PC's Comm Port?

No. The Receiver RF IN pin is where you connect the antenna.

[dhouston]

Will it be possible for me to connect the Receiver's RF In Pin to the PC's Comm Port?

No. The Receiver RF IN pin is where you connect the antenna.

[koossa]

What I mean is the RXD pin, can I connect it to the PC's Comm port.
Or do I have the wrong understanding of the RXD pin?

[thye]

Hi....I'm new here and a beginner in PICBasic Pro...

I'm using PIC 16F877A for Tx and Rx project also....what is the simple code for Tx and Rx?

Thanks a lot....

[koossa]

Dave

In your code for the receiver there is a pin for the pulsout, GPIO.1.
Is this the CD Pin?

[dhouston]

If you continue to use SerOut with the transmitter, then the receiver RXD pin output timing will be the same as RS232 but the polarity will depend on what polarity you use at the transmitter. The COM port on a PC expects inverted polarity.

However, the RF link in the example code I'm suggesting is not RS232 compatible. It is an example of the NEC protocol which is widely used for remote control and for applications like yours. X-10 uses it for all of their RF applications, including motion sensors. For an RF link it's much simpler to implement than SerIn/SerOut and is very reliable for small amounts of data. It does use Debug to output the received codes to a PC serial port. See the PBP manual for how to implement this.

I think you mean GPIO.1 and PulsIn. That is equivalent to your RXD pin. The code was written for ASK modules which have no CD so you can ignore CD if you try to adapt my code.