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.

However, it's good to see that others can make use of them. Many thanks Dave for sharing your work here.

Regards,

The Americans DONT call -12V "Gnd".

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

Peter.

Thanks for sharing this with us Dave, it should prove to be a very useful tool to the field astrophotographers!

Couple of quick Q's. You are supplying your 78L12 12v regulator chip with 12v. The normal supply voltage for these chips is 14.5v - 35v. I don't have the specific specs for the UA78L12 (which may accept a 12v input) but it may not be able to continue supplying a regulated 12v output if the input drops below 14.5v - say as your battery voltage drops. This may or may not be a problem for your electronics.

Thats what i thought too at first, however I tested it with a 12v supply and it has worked fine. Nything between 12 and 35v should be ok too. I've been operating mine off 12.2v for ages now with no ill effects.

Q2 - What for the double 1N4148 diodes coming off the UA78L12 output?

They are there to protect the 12v reg from current returning from the 5v reg. From my undertsanding these are required to ensure that the ground pin is protected. The reason there is two there is to protect in case of the first one reaching breakdown. Like a lot of things in the electronics game. I tend not to worry about what goes on very deep down. Most similar circuits I've seen use these double protection diodes. I'm not planning on breaking too much new ground!

PS - You should do an article for Sky&Tel - I'm pretty sure a lot of people would find it extremely useful... and it gets you a bit of free publicity for your website and for future projects you might want to produce commercially!

Maybe oneday Phil, even if they were to publish it, I think the last thing i need right now is a load of people looking for support!! Something to think about though.

:lol: did anyone tell the chinese of this ? :lol:

Apparently the chinese for ground is 'serrotape it to left tripod leg'

:lol: did anyone tell the chinese of this ? :lol:

Apparently the chinese for ground is 'serrotape it to left tripod leg'

thats "serrotape it to the weft twypod weg"

:lol:

(I heard there is no 'L' in the Chinese language!)