Using Linx RF modules ?

[Sam]

In what way do you feel the Holtek chips are too limiting ?

Regarding Mach3, I would have to add another parallel port card to get anymore outputs than what I have and are using now and I don't want to go that route at this point even though they are cheap.

Why wouldn't THIS with the companion receiver (just as an example), from Rentron not work for me ?

I mean if this remote can turn LEDs at the receiver on and off why couldn't it activate a PIC programmed with the correct messages and send these corresponding messages to the LCD ?

I'll look into the FSK modules also, I may already have them ???

[dhouston]

I haven't kept up with the hardware so my views may be out of date - Bruce can correct me where necessary The Holtek (and clone) decoder chips have a fixed number of data lines (4 or 8) so you have a limited number of possible codes. These may be adequate for what you want to do - I just prefer more flexibility. Doing your own protocol allows more control. Now, if you want to skip the chips and just use Holtek's encoding scheme, you can have billions of codes.

The device you linked to may well work. I just think utilizing it represents more work than doing it from scratch. Of course, I'm biased as I've done it from scratch many, many times. Once you do it from scratch, you may come to share my bias.

Also, when you wrote CNC, I thought CONTROL which is why I emphasized error detection. But, if you are merely reporting status, error detection may be less of a priority.

[Sam]

Right, status reporting is all I'm wanting to achieve with this. I do prefer to do it from scratch, I just referenced that transmitter as an example. 8 lines will be more than enough for me, 4 will will actually do just fine.

So let's say I have the Linx TX unit and I only want it to report one single button closure on the machine to the receiver 30 feet away through one wall, and I'd like to keep it as simple as possible until I start to get a hold on this as I learn pretty fast once I get one basic thing working and can experiment from there. To keep it simple, lets forget about the LCD and just light an LED for now.

How would you recommend I do this ?

Much thanks.

[dhouston]

I would use the transmitter & receiver code shown in the first two sections at

• http://davehouston.org/PIC-RX-TX.TXT

It uses the same protocol that X-10 has used successfully for 30 years. It can handle up to 256² codes and has built-in error detection.

[Sam]

That looks great, I will study it (more) and give it a try.

Thanks for all your help Dave !

Sam

[Sam]

Dave,

I've loaded your TX code into one 12F675 and connected to the Linx TX and it is transmitting data. ( I changed the interval from 15 seconds to 1.5 seconds)

I then loaded your RX code as seen below into another 12F675 and I'm not getting anything out of GPIO.2. I connected a LED to the data out of the receiver and it does flash in sync with the TX data going out.

I connect GPIO.2 of the RX PIC to Hyperterminal set at 8N1, 9600 and get nothing at all and I connected an LED to GPIO.2 and nothing there either.

Shouldn't I be getting something on the RX PIC ?

'==============================RECEIVER============================	
'-----PIC12F675-----
'USE PIC12F675 if you need to measure linear output (e.g. to tune) 
'Receives 32 bits of NEC protocol RF with initial lead-in of 8.8mS
'outputs received codes via RS232 @ 9600bps on GPIO.2

'12F675
_CONFIG
@ DEVICE PIC12F675
_NOCLKOUT  
_WDT_ON 
_PWRTE_ON
_MCLRE_OFF
_BODEN_ON
DEFINE OSC 4
INCLUDE "modedefs.bas"

DEFINE PULSIN_MAX 968				'>968 RETURNS 0
DEFINE DEBUG_REG GPIO
DEFINE DEBUG_BIT 2 				'GPIO.2
DEFINE DEBUG_MODE 1 				'Inverted
DEFINE DEBUG_BAUD 9600
DEFINE OSCCAL_1K 1

RF      VAR     byte[4]
space   VAR     byte
i       VAR     byte     
bits	VAR	byte  	         	
stx  	VAR     word            		'start of transmission

        CMCON = 7                       	'comparators off

init:	RF[0]=0:RF[1]=0:RF[2]=0:RF[3]=0
	bits=0:i=0
	PulsIn GPIO.1, 1, stx			
	If (stx<792) Then init                   
        While GPIO.1=0:Wend			'wait pulse
        'use SerIn here instead of Repeat loop & $FF tests
        Repeat
          PulsIn GPIO.1, 0, space
          If (space<40) Or (space>175) Then init
          If (space>75) Then
            RF.0(i)=1				'set bit
          EndIf
          i=i+1 
        Until (i>31)
	If RF[0]+RF[1]<>$FF Then init
	If RF[2]+RF[3]<>$FF Then init        
        For i = 0 to 3
  	  Debug (RF[i] REV 8)
        Next           
        GoTo init

        End

[dhouston]

Give me a day or two to finish something else and dig out my PIC hardware and I'll try to run this down.