Simple RF Transmit and Receive

[koossa]

Dave

Thank you for all your help

I'm not sure I know how to do this?
Must I use something like the Pulsin command, I have not done this before?

The PDF file says the CD signal has a fast response but doesn't say how fast. Instead of trying to use serin/serout I would first just look at the pulsetrain to determine if CD is fast enough that you won't miss bits.

<hr>

I am using the LED just to test if it goes low if I send data with the transmitter, just to make sure my circuit is wired correctly and that it only works if my receiver is sending data.

I have added 2 LEDs for debugging purposes.
A green one on PortB.4 and a Red one on PortB.5
If CD is low, the green LED will blink, if CD is high, the Red LED will blink.
While the transmitter is still powered down, I switch on the receiver, and the Green LED just constantly blink on and off, which tells me that the CD is Low from the beginning?
When I then swith the Transmitter on and send data, the Green LED still blink at the same frequency?

I'm not sure if I am missing something, but I am still in the amateur student phase.

Here is my code.

<code>
'************************************************* ***************
'* Name&nbsp;&nbsp;: Receiver.bas&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n bsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs p;&nbsp;&nbsp;&nbsp; *
'************************************************* ***************

Include "modedefs.bas"

DEFINE&nbsp;&nbsp;&nbsp;&nbsp; OSC&nbsp;&nbsp; 4&nbsp;&nbsp;&nbsp;&nbsp; ' Set the Xtal frequency
SerialInPin&nbsp;&nbsp; VAR&nbsp;&nbsp; PORTC.2 ' Serial Out
LEDPin&nbsp;&nbsp;&nbsp;&nbsp; Var&nbsp;&nbsp; PORTC.3
REDLed&nbsp;&nbsp;&nbsp;&nbsp; VAR&nbsp;&nbsp; PORTB.5
GreenLED&nbsp;&nbsp;&nbsp;&nbsp;VAR&nbsp;&nbsp; PORTB.4
CDPin&nbsp;&nbsp;&nbsp;&nbsp; VAR&nbsp;&nbsp; PORTD.2
DATAReceived&nbsp;&nbsp;VAR&nbsp;&nbsp; Byte
I&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; VAR&nbsp;&nbsp; BYTE
ADCON1 = 7

Main:
HIGH LEDPin
Pause 5000
Low LEDPin
&nbsp;&nbsp;
Loop:

&nbsp;&nbsp;IF CDPin = 0 THEN
&nbsp;&nbsp;&nbsp;&nbsp;HIGH GreenLED
&nbsp;&nbsp;&nbsp;&nbsp;Pause 100
&nbsp;&nbsp;&nbsp;&nbsp;LOW GreenLED
&nbsp;&nbsp;&nbsp;&nbsp;PAUSE 100
&nbsp;&nbsp;else
&nbsp;&nbsp;&nbsp;&nbsp;HIGH REDLed
&nbsp;&nbsp;&nbsp;&nbsp;Pause 100
&nbsp;&nbsp;&nbsp;&nbsp;LOW REDLed
&nbsp;&nbsp;&nbsp;&nbsp;PAUSE 100
&nbsp;&nbsp;ENDIF
Goto LOOP

END
</code>

[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?