Optimizing IR range

[ardhuru]

Hi Pablo,

Thats a nice idea; a sort of semi-universal (Pentax/Nikon/Canon) time lapse trigger.

The Canon trigger is perhaps the simplest to encode. I'm pasting my code, of which you could delete the delayed-trigger related lines. These a re used on the remote to trigger the shutter 2 seconds after the signal is sent.

    Main:
    NAP 0                           ; Reduce consumption in standby from 900uA to 116uA (cost of 18ms delay)
    IF SW1 = 0 THEN GOSUB NO_DLAY
    IF SW2 = 0 THEN GOSUB DLAY
    GOTO MAIN
 
    NO_DLAY:
    HIGH LED
    CYCLES = 16                     ; COUNTER HAS TO BE RESET TO DEFAULT!
    Gosub Pulse
    PAUSEUS 7300
    CYCLES = 16                     ; COUNTER HAS TO BE RESET TO DEFAULT!
    GOSUB PULSE
    PAUSE 50                       ; Prevent inadvertant double triggerPAUSE 500
    LOW LED
    PAUSE 500
    RETURN
  
    DLAY:
    HIGH LED
    CYCLES = 16                     ; COUNTER HAS TO BE RESET TO DEFAULT!
    Gosub Pulse
    PAUSEUS 5300
    CYCLES = 16                     ; COUNTER HAS TO BE RESET TO DEFAULT!
    GOSUB PULSE
    PAUSE 50                       ; Prevent inadvertant double triggerPAUSE 500
    LOW LED
    PAUSE 500
    RETURN
    
    Pulse:          ' THIS GENERATES "Cycles" number of 40kHz pulses (if total delays are 25)
                    ' So, for Canon, 16 Cycles of 31 uS (32.6 KHz) => Demodulated pulse of 0.496 mS
ASM
   bsf IRTX,PIN     ; 1uS, LED=on
   goto $+1         ; + 2uS = 3uS
   goto $+1         ; + 2uS = 5uS
   goto $+1         ; + 2uS = 7uS
   goto $+1         ; + 2uS = 9uS
   goto $+1         ; + 2uS = 11uS
   goto $+1         ; + 2uS = 13uS   
   goto $+1         ; + 2uS = 15uS 
   goto $+1         ; + 2uS = 17uS 
   bcf IRTX,PIN     ; 1uS, LED=off
   goto $+1         ; + 2uS = 3uS
   goto $+1         ; + 2uS = 5uS
   goto $+1         ; + 2uS = 7uS
   goto $+1         ; + 2uS = 9uS
   goto $+1         ; + 2uS = 11uS
   decfsz _Cycles,f ; + 1uS = 12S           ; This decrements in a loop till 0; then goes to next line    
   goto _Pulse      ; + 2uS = 14uS
   return           ; Return to caller    
ENDASM
  
    END

Would be nice to have your feedback on the finished product.

BTW, in your schematic you have a pullup on the switch input; cant you just enable the internal pullup?

Regards,

Anand