SparkFun Forums

[stolencdz]

I'm building a circuit that will push a button on a digital camera. I was planning to use a push-type solenoid for this. Does anyone have suggestions as to something that would be better?

Thanks.

[riden]

I think using a servo would provide a smoother depression of the shutter button.

[stolencdz]

but don't servos typically rotate? i need something that will push down.

[phalanx]

Solenoid speed is very hard to control. If you go that route, make sure you don't jackhammer the button or you could force it into an early grave.

Servos typically rotate but a simple linkage will give you linear movement.

-Bill

[SOI_Sentinel]

Depends. Do you want to use the camera for anything else, or will this live the life of a servo camera from here on out?

I've been meaning to grab a refurbed/Ebay cheap but functional long zoom digicam and hack into it to make a PIC drive ALL the controls. Use a cable or RF transmitter to send the video out back to a TV, and some control scheme to control the PIC. Now, the question is, how does current flow? Are the controller inputs the high voltage potential, or is that on the far side of the button? You'd have to solder transistors or other driver circuitry between the switch contacts and have them triggered by the PIC. Very simple after you figure out your switches.

Switches + communication would still leave enough time to drive a couple of RC servos to add pan and tilt to the motorized zoom.

Now, if you want to keep the camera whole and functional, you have a few other options. A push solenoid or an RC servo would definitely work, but you may have issues if some part gets bumped out of position. Depending on the camera, some have IR remote sensors that would work if you can determine the protocol, others have sockets for a remote switch that would allow you to "plug in" and have a solid electrical path.

(addendum) And this once again proves why I need to actually write instead of add thoughts to a post over the course of 30 minutes or so

[Philba]

wasn't there an article in N&V (or CCI?) a while ago where the author did just that. As I recall, he made a little connector and was able to use the camera both ways.

[stolencdz]

I'm unfamiliar with the publications you mentioned. What do they stand for?

[phalanx]

N&V = Nuts and Volts. It's a great publication for the electronics hobbiest. I've had a subscription for the past 6 years.

The only thing that comes to mind for CCI is CCI Camera City which is a store and not a publication.

-Bill

[wiml]

CCI is probably "Circuit Cellar INK". It's another good magazine. Targets a more professional audience than N&V, but lots (most, really) of the articles are reasonably-skilled-hobbyist level things (the excuse is that they can still help you broaden your professional skillset or whatever, but I suspect it's also that they're more fun. And I'm sure they know they have a fair number of hobbyist readers, like me.)

Re the camera pushbutton, if it's a simple switch, a reed relay is probably easiest. You don't have to worry about voltages or anything then. It might not be a simple switch, though --- my digital camera's button can be depressed halfway to make it focus before you shoot, so it must have an extra contact in there.

[beebop]

A quick way to turn rotation linear; a cam would do it, no?

Hey, those are both good reads, usually.

Regards,
Robert

[Philba]

yes. as was said, n&v is nuts and volts, cci - circuit cellar

One thing to remember about digital camera shutter switches is that there are two positions. halfway down allows focus and exposure calculations and then all the way down captures the image. I would want to support this to get better timing of the shot. adds some complexity to the servo based solution.

I believe these 2 switches are either pulled-high or low. If you figure out which way, you can use a simple transistor to pull it the other way and mimic switch closure. alternativelyy, you could use just logic output though you might want to be careful not to exceed the camera's Vcc.