New to the forums and relatively new and inexperienced with CHDK and also electronics.
Sorry about the long post and hope it is in order and in the right place.
I went looking for a instructions on building cheap wireless remote for a Canon point & shoot camera using the exciting CHDK remote shutter facility.
OK, I have searched the web and found many references to remotes for either
(a) More advanced Canon cameras that have a mini jack socket and or IR receiver built in to allow remote picture taking.
(b) Wired remotes utilizing the CHDK hack and the Mini USB socket.
But very few meeting my requirements for a wireless version.
Now on reading these and also the CHDK forums it seems that the voltage sensed from the USB connection can be as little as 3 volts for some cameras, or as high a 4.5 volts for others. I have a Powershot 720 IS and it appears that it is unlikely to function reliably operating at only 3 volts However any voltage above 5.5 volts might be dangerous to the camera.
Now checking relevant postings I found some references to using Chinese made wireless doorbells and RC model controllers. As the doorbells were listed as operating on 3 volts and the RC models controllers were more expensive, I seized on one article that mentioned the possibility of using a cheap [admin: avoid swearing please] or burp machine.
I found one on sale at
+machine&form=KEYWORD]http://www.jaycar.co.nz/productView.asp?ID=GH1088&keywords=[admin: avoid swearing please]+machine&form=KEYWORDThis one was powered by 4 AAA cells so the 6 volts looked a bit risky. Because of this risk I put the burper away in a cupboard and forgot about it. However we are planning a trip and when travelling a remote could be very usefull so out came the burp machine and I set about modifing it.
Reviewing some articles I I checked
http://www.hackersbench.com/Projects/ding-dong/main.html which commented on the likely waveform and then I found Philip Schutz description using and opto coupled triac (MOC 3020)
http://digital-photography-school.com/how-to-make-a-remote-shutter-release-from-a-doorbell-diy-specialUsing the MOC 3020 looked like it would solve the excess voltage problem, so out came the soldering iron.
First I removed the speaker and connected the speaker wires to a LED. Pushing the remote button resulted in the LED glowing, but not that brightly, for about 2 seconds .
I decided to give it a try anyway and drilled holes and installed the opto coupler. Luckily the battery holder had solder lugs at the end of each cell so tapping the coupled power supply at the 3rd cell (4.5 V) was easy.
Shaking in fear and trepidation I connected it all up and switched on the camera and receiver. Pushing the remote button was followed a couple of seconds later by the camera's focusing beam coming to life and YES !.Success! It took a picture.
But, after 10 seconds or so it took another and then another and so on ad infinitum?
After several more tries it took a picture and then semed to freeze with the recorded picture showing on screen but I was getting no reaction to any camera controls until I switched the camera off or I removed the USB plug.
My guess is that perhaps there is s some bounce in the switching from the MOC although connecting up a multimeter showed just a roughly 2 second pulse of 4+ volts but my meter has a very slow, or nil, reponse to transient spikes.
I have Canon 720 IS.... CHDK a720-100c-0.9.8-827-. Script Remote.bas I have used the script with a wired remote switch 4.5 V and it works as expected.
Help! Please, has any one got any ideas to solve my problem?
Setup:http://www.flickr.com/photos/38437603@N04/4092468356/sizes/o/
