Camera switch using a servo - comments please - RC Groups
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Mar 07, 2004, 01:21 AM
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Camera switch using a servo - comments please

I am currently designing a camera switch that controls a servo to trigger the shutter. This idea originated in another thread:

The idea is that this simple PIC circuit sits between the receiver and the servo and provides useful features that are not available with a direct servo connection. These include:

- keep-alive function for those cameras where you can't disable the sleep mode
- repeatable, precise positioning of the servo for shutter triggering

My preliminary documation is here:

If anyone has any comments on this, or suggestions for other features I will consider them. I am, of course, particularly interested if this device already exists - reinventing wheels is a waste of everyone's time.

Thanks in advance,
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Mar 07, 2004, 03:07 AM
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Regarding power off on Loss of Signal:

The idea here is that this would occur on a significant loss of signal, not just a glitch. What I was aiming for was to reduce the power load by allowing the camera to shutdown and stop the camera servo using power as well. If you have an LMA you want as much power as possible for that.

Have I built and tested this yet?

No, I just prepared the design document first. When I have some feedback I will complete the programming and testing. Then it will get some QA testing. After all that it will be available for anyone to use.

Mar 07, 2004, 08:38 AM
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Ironsides's Avatar

Two Stages


Excellent design documentation.

Some of the high end cameras require a two stage trigger. Perhaps a jumper could be used to elect this option.

First pressure = focus and exposure evaluation: Second pressure = shutter trigger.

Thus, in two stage operation we need:

1. A way to adjust servo throw to achieve first pressure
2. A momentary pause
3. A way to adjust servo throw to ensure shutter trigger.

This is covered in some depth by Fuchs as per:


Mar 07, 2004, 09:08 AM
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Randy Due's Avatar

Sounds great!

Oct 08, 2004, 08:17 AM
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d.o.a. switch

Hi Tugboat and other fellows aerial photographers,
I tried your design at without any result. The PIC looks dead in op mode as in prog mode. I'm sure of my hardware and programming tools. Is it somebody who successfully made one? Your project looks so great, can you give me some hints?
Oct 08, 2004, 08:47 AM
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I apologize!
I just pasted the wrong link, I'm really talking of this one:
Oct 08, 2004, 10:46 PM
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I have responded to your email about this. It should work fine and shouldn't take long to get it working for you.

Oct 09, 2004, 07:22 AM
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Thank you Tim,
I just sent you details about the issue.
Oct 11, 2004, 11:51 PM
Registered User

Great design!

Thank you so much Tim!
You targetted exactly where I missed. My programming software's default set-up
erases before writing the Pic and put 3FF in the calibration location. I just replaced this value with '3480' as you suggested me and Hocus Pocus the little guy came to life! Your device does everything for my needs and lets me concentring on the flight, not on managing the arm position of a servo.
A real jewell of Pic programming and design.