Build your own device to control Canon DSLR's

It's on days like this I think I should have studied electrical engineering! I'm afraid most of the diagrams and terminology don't mean much to me.

Thats an interesting point. One thing on the TTD list is to provide a stripboard layout so that people can build the unit without having to understand anything about what is going on behind the scenes. Doing this can be a great way to gently introduce people to the field of electronics. I became interested after assembling a couple of kits I bought from maplins a few years ago.

The Americans DONT call -12V "Gnd".

That could lead you into to all sorts of trouble !!!!

Peter.

It sure can, for a second I thought you were using a positive and negitive supply, with a center ground, not a common thing to do in circuits like this, but its great for audio amplifiers to play some loud music on

If you do wire -12v to Gnd the error signals you get will indeed be "American".

They will be Native American smoke signals!

Peter.

Nice one Dave.

I've had a look at your circuit and it's so simple anyone could build it. Aren't PICs great. How long did it take to get the code working satisfactorily?

Question - why bother with the 12V regulator? The 78L05 will take anything up to 30V input. You could then lose D2 and D3 also, as D1 will handle any reversed inputs. Also D1 as an 1N4007 is probably overkill it'll handle 1000V reversed repetitive, you could probably get away with an 1N4001 at 50V, after all there aren't too many of us out there with 50V DC supplies, worse case is usually a 24V reversed input.
Just Curious!

I'll certainly be ordering a programmed PIC from you (V1.2 of course) in the new year. Just got word that my 350D is shipping today, so I'll be doing all the mods as I go.

Well done again!!!

Just so there is no confusion I've removed the -12V symbol on that diagram.

I've had a look at your circuit and it's so simple anyone could build it. Aren't PICs great. How long did it take to get the code working satisfactorily?

Hi John,

I bought a piece of software called PIC Simulator IDE. It allows you to write your code in BASIC, compiles it to hex and also has a very good simulator so you can test the code without having to plug the MCU in and out repeatedly. I had spent days writing the code in assembly. Once I got the new software I had in done in almost one evening.

Question - why bother with the 12V regulator? The 78L05 will take anything up to 30V input. You could then lose D2 and D3 also, as D1 will handle any reversed inputs. Also D1 as an 1N4007 is probably overkill it'll handle 1000V reversed repetitive, you could probably get away with an 1N4001 at 50V, after all there aren't too many of us out there with 50V DC supplies, worse case is usually a 24V reversed input.
Just Curious!

The reason the 12V reg is there is to allow the 5v handle the current. The circuit very slightly overloads the 5V but I found an article by a guy who explained that using the 12V on first allows the second reg to be underrated a bit. It was in EPE mag somewhere! Without it I probably would have had to use a higher rated 5V reg which would probably mean using a TO220 package which I wanted to avoid. It might work without it, I just didnt want to take the chance.

As for the diode, well to be honest, thats all I had in stock at the time:D 1N4001 would work well too. However I didn't want to publish a diagram with components which I hadn't specifically tested myself!

I'll certainly be ordering a programmed PIC from you (V1.2 of course) in the new year. Just got word that my 350D is shipping today, so I'll be doing all the mods as I go.

I'll be bringing a few along to the various star parties, that will save folks on the shipping. The current RS price for the MCU is €4.86 including VAT and shipping, they will be available with V1.2 pre-programmed at that price.

Well done again!!!