TI-86 Intervalometer for Canon XTi

I just came across this instructable yesterday and forgot all about that TI-86 in my backpack buried somewhere in the closet. So I dug it out, found the 2.5mm cable and gave it a whirl using my Canon 400D. It didn’t work at first, but after a bit of googling all I had to do was splice the cable (red and white on the calculator side to red on the camera side then reconnect ground) and make sure the camera was in manual focus. It worked!

Here’s the first test run:

I was inspired by this, but somewhat unhappy with the lack of options using the code supplied in the instructable. It’s been almost a decade since the last time I programmed something in TI-BASIC, but alas, I wanted more options. So I hacked away and ended up making 3 basic modes for the intervalometer:

Shoot: Fires the shutter at will by pushing the F1 button
XLoop: Input a number and interval and it will shoot that number of times at the given interval
Lapse: For extra long time lapses, loops infinitely and exposes at the supplied interval

The loop and lapse modes also display the number of shots. Code for the program is below:

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:Lbl Z
:ClLCD
:Disp "XTiControl V 0.5","","Approx Intervals:","800 = 5sec","2000 = 10sec"
:Menu(1,"Shoot",R,2,"XLoop",L,3,"Lapse",A,5,"Quit",Q
:End
:
:Lbl Q
:ClLCD
:Stop
:
:Lbl R
:ClLCD
:Disp "Ready to fire"
:Menu(1,"Fire",F,5,"Quit",Z
:End
:
:Lbl F
:1->E
:ClLCD
:Disp "Shooting..."
:Send(E)
:Goto R
:End
:
:Lbl L
:ClLCD
:Input "How many shots? ",N
:Input "Interval: ",I
:ClLCD
:For(B,1,N
:ClLCD
:Disp "Shooting: "+B	
:For(T,1,I
:End
:Send(B)
:End
:Goto Z
:
:Lbl A
:ClLCD
:Input "Interval: ",V
:1->X:While X>0
:ClLCD
:Disp "Shooting: ",X
:Disp "","","","","Press ON to quit"
:For(H,1,V
:End
:Send(V)
:X+1->X
:End