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[on:]

Hello,
I hope this is a simple question...
I am a visual artist and I embed digital photo frames to play videos in my sculptures. The problem is, is that no digital photo frames that I can find play video right away on start up...you always have to press a series of buttons to get the video going.
What I did in the past is just soldered onto the buttons and extended them so that you didn't have to reach into the sculpture to press the button and get the video going. But I'd like to use an Arduino to send a signal to the button to press it. So say I need to press one button, wait a few seconds and press it again, is this is simple as making a digitalOut and setting it to HIGH, delaying, set it to LOW, then setting it to HIGH and LOW again? Would it be even easier(cheaper) to just program a smaller AVR chip to do this, if I really wanted a bare bones setup? There's probably some stuff with voltage that I don't understand so anything you can help me with is much appreciated!
Thanks so much for any feedback!

[Reply #1 on:]

Hello,
I hope this is a simple question...
I am a visual artist and I embed digital photo frames to play videos in my sculptures. The problem is, is that no digital photo frames that I can find play video right away on start up...you always have to press a series of buttons to get the video going.
What I did in the past is just soldered onto the buttons and extended them so that you didn't have to reach into the sculpture to press the button and get the video going. But I'd like to use an Arduino to send a signal to the button to press it. So say I need to press one button, wait a few seconds and press it again, is this is simple as making a digitalOut and setting it to HIGH, delaying, set it to LOW, then setting it to HIGH and LOW again? Would it be even easier(cheaper) to just program a smaller AVR chip to do this, if I really wanted a bare bones setup? There's probably some stuff with voltage that I don't understand so anything you can help me with is much appreciated!
Thanks so much for any feedback!

Yes it is conceptually as simple as that. However because of possible voltage differences and unknown circuit details for the digital frame device, it's often simpler to have the arduino turn small relays on and off with digital commands and wire the relay contacts across the devices' switches. That way there is no need to know the voltage, current value or polarity of the frames button circuits. One relay for each switch you have to control. Here is an example of a small +5vdc relay that an arduino output pin can drive directly. http://www.allelectronics.com/make-a-store/item/RLY-541/5-VDC-SPST-N.O.-DIP-REED-RELAY/1.html
One should wire a reversed biased diode across each relay coil for transient protection.

Lefty

[Reply #2 on:]

Using a smaller AVR may indeed  also be possible, depending on numbers of screens/buttons and the program of button-pushing you're emulating. Should you only need to show the next videos/photos using 6 buttons max, you probably could use the cheapest AVR-chip.

[Reply #3 on:]

thanks for the help! Lefty, do you know a good schematic anywhere for wiring up that relay? I would still use a tip120 or some sort of transistor, no? does this circuit look good? http://www.flickr.com/photos/anachrocomputer/3242387876/in/photostream/
it's good to know that i can drive the relay with the arduino...having three wall worts for one video would be a little ridiculous...

[Reply #4 on:]

thanks for the help! Lefty, do you know a good schematic anywhere for wiring up that relay? I would still use a tip120 or some sort of transistor, no? does this circuit look good? http://www.flickr.com/photos/anachrocomputer/3242387876/in/photostream/
it's good to know that i can drive the relay with the arduino...having three wall worts for one video would be a little ridiculous...

That circuit (using a transistor to switch the relay) would work fine. However that relay I linked for you only consumes 10ma of current, so an arduino output pin can drive it directly without a transistor if you desired. If you do wish to not use a transistor then just wire one side of the relay coil to an output pin and the other side of the coil to ground. You should still use a diode like shown in the circuit, but wire the diode right across the relay coil terminals with the anode side of the diode wired to the grounded side of the relay. The two relay contact terminals of course just wire directly across the switch contacts you are controlling.

Lefty