IR Counter

[flotulopex]

Hello Partime,

I made a self-learning IR remote (with lots of help from people in this forum).

Maybe you can help some helpfull stuff in the code (especially LEARN and SEND routines).

Have a look here http://home.citycable.ch/flotulopex/...I_Frames_e.htm

[Archangel]

Hello Partime,

I made a self-learning IR remote (with lots of help from people in this forum).

Maybe you can help some helpfull stuff in the code (especially LEARN and SEND routines).

Have a look here http://home.citycable.ch/flotulopex/...I_Frames_e.htm

Roger, Nice ! I like your website ! Interested in that self learning remote too.

[partime]

Thank you picster and Roger for the information you presented.

I finally captured the signal from my remote as dhouston suggested. I couldn't get Loop Recorder to capture the signal, but I did get it with a different program (http://www.passmark.com/products/soundcheck.htm). I attached a copy of the signal I captured. It is from a Hitachi CLU-5722TSI remote's channel up button. The bottom one is the full signal. The top ones are of the signal divided into two segments.

The signal seems to follow this protocol that I found for Hitachi.

Code length:            32 bits
Carrier:                39.2kHz

The code is only transmitted once, and after that a stop code is transmitted.



	     +--------------------------------+                   
Header:      |                                |                  
	     +                                +----------------+..
			    16T                       8T
			   8.8ms                     4.4ms

	     +--+      
1 is coded:  |  |      
	   ..+  +------+..
	      T   3T

	     +--+  
0 is coded:  |  |  
	   ..+  +--+..
	      T  T 
			 +--+
			 |  |
After the last bit a ( ..+  +  ) is transmitted to terminate the last bit.
			  T

	      +--------------------------------+        +--+
Stop code:    |                                |        |  |
	      +                                +--------+  +
			      16T                  4T     T
			     8.8ms                2.2ms

T = 550us

What should the next step be? Should I try to write some code using PULSIN to read the incoming IR signal?

[dhouston]

That's the NEC protocol. It's one of the oldest and is used by more manufacturers than any other. It's very reliable as it has error detection built in (although some implementations do not use that). I have shown how to send/receive it (as RF) in this thread http://www.picbasic.co.uk/forum/showthread.php?t=6261. You just have to account for the fact that the IR receiver is active low while the RF receiver is active high. There is a link within that post to a NEC datasheet that explains it completely. I've decoded the third image and attached it. Hitachi is using error detection - the first two bytes sum to FF as do the third and fourth bytes.

[dhouston]

I just looked at your diagram. That's not a Stop Code - it's a Repeat Code. That reduces battery drain compared to repeating the full code.

[partime]

Thanks again for your help Dave. I pretty much used your RF receiver code and modified it for use with the IR signal. Here is the code I used on an 16F84A with a 4 MHz crystal. I used it to test if the channel up button was pressed on the remote.

define PULSIN_MAX 968

IRPIN           var     PORTB.0
LED             var     PORTB.1
LED2            var     PORTB.2
RF              var     byte[4]
Header          var     word
PULSE_LENGTH    var     byte
i               var     byte

INIT:   RF[0]=0
        RF[1]=0
        RF[2]=0
        RF[3]=0
        i=0
        Pulsin IRPIN, 0, Header
        if (Header < 792) then INIT
        while irpin = 0:wend
        repeat
            pulsin IRPIN, 1, PULSE_LENGTH
            if (PULSE_LENGTH < 40) or (PULSE_LENGTH > 175) then INIT
            if (PULSE_LENGTH > 90) then 
                RF.0(i) = 1
            else
                rf.0(i) = 0
            endif
            i=i+1
        until (i>31)
        if (RF[3]=230) then 
        high LED
        pause 500
        low LED
        else
        high LED2
        pause 500
        low LED2
        endif
        goto INIT
end

I get LED to go high when I press the channel up button.

It took me awhile to figure out how the data was arranged in the array. I started out using RF[0]=10 to light LED, but kept getting LED2 to light up. So, I thought there was something screwed up with the values pulsin was generating. Finally, I read through the FAQ on arrays and figured out my problem. I used RF[0]=80 and got LED to light up. However, LED would light up with any button I pushed since all the buttons used the same starting code. So, I ended up using RF[3] to test if channel up was pressed.

Is testing RF[3] going to be the best way to determine which button is pushed? I plan to use channel up/channel down for one team and volume up/volume down for the other team.

[dhouston]

Is testing RF[3] going to be the best way to determine which button is pushed? I plan to use channel up/channel down for one team and volume up/volume down for the other team.

The way most use this protocol, RF[0] indicates a device (e.g. TV, CD player) and RF[2] indicates a button (e.g. number, Vol+). RF[1] is the bitwise complement of RF[0] and RF[3] is the bitwise complement of RF[2]. So, you are probably safe using either RF[2] or RF[3].

I would suggest a change...

        while irpin = 1:wend

That merely waits until the initial space part of the header passes. With RF I found that was necessary.