Wire worked by not wireless

[mankan]

Dear Gurus,

Below is the code I am using to build a wireless data transfer, I started by building a wired connection and it worked very fine but once I go wireless nothing works.

Any idea, hint, help is greatly appreciated.

Thanks,
Mankan

'************************************************* ***************
'* Name : Receiver.BAS *
'* Author : [select VIEW...EDITOR OPTIONS] *
'* Notice : Copyright (c) 2006 [select VIEW...EDITOR OPTIONS] *
'* : All Rights Reserved *
'* Date : 5/10/2006 *
'* Version : 1.0 *
'* Notes : *
'* : *
'************************************************* ***************

INCLUDE "modedefs.bas"

'@DEVICE PIC16F628, WDT_ON
'@DEVICE PIC16F628, BOD_ON
'@DEVICE PIC16F628, PROTECT_OFF
'@DEVICE PIC16F628, MCLR_ON

DEFINE OSC 4
DEFINE NO_CLRWDT

'* Variable declarations
Header var BYTE
Counter VAR BYTE
Packet VAR BYTE
End_Of_Data VAR BYTE

counterA VAR BYTE
ErrorFlag var bit
MyData var byte
ManchesterWord Var WORD

Temp_Byte var byte[5]
Temp_Word var WORD[5]
x VAR BYTE
send_word VAR WORD

SYNCH VAR byte
SYNCH=$C6


CMCON = 7
VRCON = 0
TRISB.1 = 1

INPUT PORTB.1
PORTB.1 = 1

pause 10
Loop:
Header = 0
HIGH PORTB.6
'SERIN PORTB.1,N300,[SYNCH],Header,Counter,Packet,End_Of_Data
'SERIN PORTB.1,N300,[SYNCH],ManchesterWord.lowbyte,ManchesterWord.highbyte
SERIN PORTB.1,N300,[SYNCH],send_word.lowbyte,send_word.highbyte
Temp_Word[0] = send_word
For x=1 to 4
SERIN PORTB.1,N300,300,Loop,send_word.lowbyte,send_word. highbyte
Temp_Word[x] = send_word
next x

for x=0 to 4
ManchesterWord = Temp_Word[x]
GOSUB DecodeManchester
Temp_Byte[x] = MyData
next x

Low PORTB.6
Header = Temp_Byte[0]
PAUSE 100
if Header = 96 THEN
gosub GLOW_PIN7
if Counter = 2 Then
gosub glow_pass
ENDIF
endif
goto loop

TimeOut:
call GLOW_TIMEOUT
goto loop

GLOW_PASS:
HIGH PORTB.5
PAUSE 50

LOW PORTB.5
PAUSE 50
RETURN

GLOW_PIN7:
HIGH PORTB.7
PAUSE 50

LOW PORTB.7
PAUSE 50
RETURN

GLOW_TIMEOUT:
HIGH PORTB.6
PAUSE 500

LOW PORTB.6
PAUSE 500
RETURN

DecodeManchester:
ErrorFlag=0
For counterA=0 to 7
if ManchesterWord.1=0 then
MyData.7=0
If ManchesterWord.0=0 then ErrorFlag=1
else
MyData.7=1
If ManchesterWord.0=1 then ErrorFlag=1
endif
ManchesterWord=ManchesterWord>>2
if counterA<7 then MyData=MyData>>1
next counterA
return

/**********END OF Receiver*********************/

/**********Start of Transmitter*********************/
'************************************************* ***************
'* Name : Transmitter.BAS *
'* Author : [select VIEW...EDITOR OPTIONS] *
'* Notice : Copyright (c) 2006 [select VIEW...EDITOR OPTIONS] *
'* : All Rights Reserved *
'* Date : 5/2/2006 *
'* Version : 1.0 *
'* Notes : *
'* : *
'************************************************* ***************

INCLUDE "modedefs.bas"

DEFINE OSC 4
DEFINE NO_CLRWDT


CMCON = 7
VRCON = 0
TRISB.2 = 0

Header VAR BYTE
End_Of_Data con 24
SYNCH VAR byte
SYNCH=$C6

'* Variable declarations
Counter VAR BYTE
Packet VAR BYTE

counterA VAR BYTE
MyData var byte
Temp_Byte var byte[5]
Temp_Word var WORD[5]

ManchesterWord Var WORD
x VAR BYTE
send_word VAR WORD

Header = 96


pause 10
OUTPUT PORTB.2
PORTB.2 = 0
OUTPUT PORTB.4
PORTB.4 = 0
OUTPUT PORTB.5
PORTB.5 = 0

Counter = 2
Packet = 78


Temp_Byte[0] = 96
Temp_Byte[1] = 16
Temp_Byte[2] = 26
Temp_Byte[3] = 36
Temp_Byte[4] = 46

start:
pause 1000
MyData = Header
for x=0 to 4
MyData = Temp_Byte[x]
gosub EncodeManchester
Temp_Word[x] = ManchesterWord
nEXT X
'SEROUT PORTB.2,N300,[126, SYNCH,Header, Counter, Packet, End_Of_Data]
'SEROUT PORTB.2,N300,[126, SYNCH,ManchesterWord.lowbyte, ManchesterWord.highbyte]
SEROUT PORTB.2,N300,[1263, SYNCH]
for x=0 to 4
send_word = Temp_Word[x]
PAUSE 1
SEROUT PORTB.2,N300,[send_word.lowbyte, send_word.highbyte]
next x
CALL GLOW_LED
goto Start

GLOW_LED:
HIGH PORTB.5
PAUSE 50

LOW PORTB.5
PAUSE 50
RETURN

EncodeManchester:
ManchesterWord = 0
for counterA=0 to 7
if MyData.0 = 0 then
ManchesterWord.14=1
else
ManchesterWord.15=1
endif

if CounterA<7 then ManchesterWord = ManchesterWord>>2
MyData=MyData>>1
Next CounterA
return

/************END OF TX****************/

[Christopher4187]

I'm not one of the most experienced people on this forum but I have made successful links with PIC's without wires. Can you tell us what you are using in the way of hardware? If your code works with wires, your code should work without wires. Have you ever done a wireless link with PIC's before?

Chris

[Christopher4187]

I forgot to mention, it is possible that your software may have an issue with timing. When I use a wireless link, I typically give a little more time for the transmit and receive signals....maybe an extra 10 to 20ms.

[mankan]

Chris,

Thank you very much for the reply. This is my first project with the PIC. Is there any other issue apart from time-to-transmit?

Do you see anything wrong with my code? It worked fine with the wires.I have even grounded the Rx DataIn pin to overcome the noise.

I am using laipac 434 series of Tx/Rx.

Thanks,
Mankan

[Christopher4187]

I have never used those but I have used Linx Technologies LR series modules. I found that without a 10K pullup resistor (to +5V) on the RX side, they would not work at all. The TX side did not need anything. Are you making only a transmitter and receiver or are you making two transceivers. Don't forget that you cannot have to transmitters transmitting at the same time. With the Linx modules, if you don't pull down the PDN line, the transmit port will always be open making it impossible to send data. Of course, if only using one TX and one RX, this is not a problem. The other thing you may look at is interference in the surrounding area. Let me know if you still have problems.

[dhouston]

The Laipac modules (also widely available under other names) use ASK and the suprerregenerative receiver has AGC/ATC so the output line will have continuous noise in the absence of a signal. I would not try to use serial in and out but would use some type of preamble that will serve to tell the receiver that a message is coming and also allow it to set its AGC/ATC. I use the NEC IR protocol and have never had much of a problem sending/receiving. However, it may or may not be the best choice depending on the type of data you need to transmit. The length of messages casn be a determining factor.

I don't recall what Bruce Reynolds uses in his examples but he does have some examples using these modules on his web site.