Transmission works with wires but not always with wireless

[jyi1]

I would use a 5ms pulse as the preamble and a 20ms pause between data packets (it allows the AGC and threshold to reset).
On the receiving end I would use PulsIn to wait for the 5ms pulse and then go into the normal receive routine once it's received. Using some type of error detection (e.g. checksum) is a necessity.

What range do you need? How much data do you need to send?

Looking at the digital data pin with a 'scope (or recording it with a soundcard as I suggested earlier) can eliminate a lot of guesswork by telling you whether your signal strength is adequate. I find it invaluable.

Is the code that I wrote below what you are trying to tell me?
I am only trying to send 4 bits (8 bits encoded). I looked at the digital data pin of the scope and my signal has an amplitude of about 3.72 v.

Transmit:
Pulsout PORTB.7, 500
Pause 20000
serout PORTB.7, n2400, [$aa,encoded2]
Pause 20000

Receive:
Wait55:
Pulsin PORTB.0,1,ct55
If ct55 = 500 Then
goto Waitaa
Else
goto Wait55
Endif
'goto Wait55

Waitaa:
serin PORTB.0, n2400, encoded1
If encoded1 <> $aa Then goto Maina
serin PORTB.0, n2400, encoded1
write 0, encoded1

[dhouston]

Is the code that I wrote below what you are trying to tell me?
I am only trying to send 4 bits (8 bits encoded). I looked at the digital data pin of the scope and my signal has an amplitude of about 3.72 v.

Transmit:
	Pulsout PORTB.7, 500
	Pause 20000
	serout PORTB.7, n2400, [$aa,encoded2]
	Pause 20000

Receive: 
Wait55:
        Pulsin PORTB.0,1,ct55
        If ct55 = 500 Then 
           goto Waitaa
        Else
          goto Wait55
        Endif
        'goto Wait55

Yes, more or less. I would change it to...

Transmit:
	Pulsout PORTB.7, 500
	Pause 2500     'shorten space
	serout PORTB.7, n2400, [$aa,encoded2]
	Pause 20000

Receive: 
Wait55:
        Pulsin PORTB.0,1,ct55
        If ct55 < 450 Then Wait55
        goto Waitaa

The important thing with the signal is that it be clean with no noise pulses interspersed with the data.

With only 4 bits, I think I would use a variation of the NEC protocol, sending only 1 byte with each code. The NEC protocol has error detection built in so you can discard any corrupted codes. Read the NEC protocol documentation in the link I cited earlier and if you still have questions I'll try to answer them here.

[jyi1]

Yes, more or less. I would change it to...

Transmit:
	Pulsout PORTB.7, 500
	Pause 2500     'shorten space
	serout PORTB.7, n2400, [$aa,encoded2]
	Pause 20000

Receive: 
Wait55:
        Pulsin PORTB.0,1,ct55
        If ct55 < 450 Then Wait55
        goto Waitaa

The important thing with the signal is that it be clean with no noise pulses interspersed with the data.

With only 4 bits, I think I would use a variation of the NEC protocol, sending only 1 byte with each code. The NEC protocol has error detection built in so you can discard any corrupted codes. Read the NEC protocol documentation in the link I cited earlier and if you still have questions I'll try to answer them here.

I tested out the above code thats included in my code and it does not work by wireless or by wire.

[dhouston]

I'm not going to try to read your unformatted code or write the entire application but here are code snippets that show you what you need to do. It sends 4 bits both "as is" and as bitwise complement using a variation of the NEC protocol. I've hardcoded the 4 bits of data as 1101. This is adapted from code I use to send and receive 2-4 bytes so the pins are the ones I used. There are more efficient ways to do things but I've tried to show it step-by-step so you see the logic.

'-----Transmit-----
SendRF: wb.0=data0  '00000001
        wb.1=data1  '00000001 
        wb.2=data2  '00000101
        wb.3=data3  '00001101
        wb=~wb      '11110010
        wb=wb<<4    '00100000
        wb.0=data0  '00100001
        wb.1=data1  '00100001
        wb.2=data2  '00100101
        wb.3=data3  '00101101
        'bits 0-3=data, bits 4-7=~data
        Low 4
	For c=1 To Copies
	  PulsOut 4, 500
          PauseUs 2500
	  For i=0 To 7
	    PulsOut 4, 50
	    If wb.0=1 Then
	      PauseUs 1500
	    Else
	      PauseUs 500
	    EndIf 
	    wb=wb>>1
	  Next
	  PulsOut 4, 50
	  Pause 20			
	Next

'-----Receive-----	
DEFINE PULSIN_MAX = 550
	
RcvRF:  PulsIn GPIO.1, 1, STX
        wb=0
        If STX<450 Then RcvRF
        While GPIO.1=0:Wend
        For i = 0 To 7
          PulsIn GPIO.1, 0, space
          If (space<40) Or (space>175) Then RcvRF
          If (space>75) Then
            wb.0=1				
          EndIf
          wb=wb<<1
        Next i	
        comp=wb>>4
        wb=wb & 7
        If wb + comp = 15 Then
          'wb is good data
        Else
          'wb is corrupt
        EndIf

[jyi1]

I'm not going to try to read your unformatted code or write the entire application but here are code snippets that show you what you need to do. It sends 4 bits both "as is" and as bitwise complement using a variation of the NEC protocol. I've hardcoded the 4 bits of data as 1101. This is adapted from code I use to send and receive 2-4 bytes so the pins are the ones I used. There are more efficient ways to do things but I've tried to show it step-by-step so you see the logic.

'-----Transmit-----
SendRF: wb.0=data0  '00000001
        wb.1=data1  '00000001 
        wb.2=data2  '00000101
        wb.3=data3  '00001101
        wb=~wb      '11110010
        wb=wb<<4    '00100000
        wb.0=data0  '00100001
        wb.1=data1  '00100001
        wb.2=data2  '00100101
        wb.3=data3  '00101101
        'bits 0-3=data, bits 4-7=~data
        Low 4
	For c=1 To Copies
	  PulsOut 4, 500
          PauseUs 2500
	  For i=0 To 7
	    PulsOut 4, 50
	    If wb.0=1 Then
	      PauseUs 1500
	    Else
	      PauseUs 500
	    EndIf 
	    wb=wb>>1
	  Next
	  PulsOut 4, 50
	  Pause 20			
	Next

'-----Receive-----	
DEFINE PULSIN_MAX = 550
	
RcvRF:  PulsIn GPIO.1, 1, STX
        wb=0
        If STX<450 Then RcvRF
        While GPIO.1=0:Wend
        For i = 0 To 7
          PulsIn GPIO.1, 0, space
          If (space<40) Or (space>175) Then RcvRF
          If (space>75) Then
            wb.0=1				
          EndIf
          wb=wb<<1
        Next i	
        comp=wb>>4
        wb=wb & 7
        If wb + comp = 15 Then
          'wb is good data
        Else
          'wb is corrupt
        EndIf

If I were to run your code to test it would I code data0=0000001, data1=00000001, data2=00000101, data3=00001101 and then code data0=001000001, data1=00100001, data3=00100101, data3=00101101? Also in the for c=1 to Copies, what is Copies supposed to mean?Also, I discover that when I use my old code and send it through once and view the digital output of the receiver and transmitter input the on the oscilloscope the sequence appears but it does not get picked up by the microcontroller.

[skimask]

If I were to run your code to test it would I code data0=0000001, data1=00000001, data2=00000101, data3=00001101 and then code data0=001000001, data1=00100001, data3=00100101, data3=00101101? Also in the for c=1 to Copies, what is Copies supposed to mean?Also, I discover that when I use my old code and send it through once and view the digital output of the receiver and transmitter input the on the oscilloscope the sequence appears but it does not get picked up by the microcontroller.

Call me crazy...but I think between this thread and the other one, you're making the program/process entirely much harder than it needs to be...

[dhouston]

Call me crazy...but I think between this thread and the other one, you're making the program/process entirely much harder than it needs to be...

OK. You're crazy!

[dhouston]

data0-data7 represents the 8 bits of the single byte being transmitted.

        data.bit0 = 1
        data.bit1 = 0
        data.bit2 = 1
        data.bit3 = 1
        data.bit4 = 0
        data.bit5 = 1
        data.bit6 = 0
        data.bit7 = 0

Copies means the number of times the transmission is repeated. You will need to experiment. If you always have a strong signal you might get by with a single copy; a weaker signal will require additional copies to set the receiver AGC and threshold. Most X-10 RF transmitters send 5 copies.

What I usually do on the receiving end is report the first valid code and then only report subsequent codes if they differ - with a time limit based on the time required to send the five (or whatever) copies.

[dhouston]

If I were to run your code to test it would I code data0=0000001, data1=00000001, data2=00000101, data3=00001101 and then code data0=001000001, data1=00100001, data3=00100101, data3=00101101?

You said you are sending 4 bits of data. My example was intended to show you how to send the 4 bits twice in two different ways. One way is "as is" in the lower 4 bits of wb; the other way is as the bitwise complement of the 4 data bits in the upper 4 bits of wb. Sending it in two forms allows us to check for errors on the receiving end.

Assuming you want to send %1101...

data=%1101
wb=data
wb=~wb
wb=wb<<4        'bitwise complement %0010 in upper 4 bits 
wb=wb+data      'data "as is" in lower 4 bits

The attached GIF shows the waveform for data=%1101.