Modifying a controller to simulate button press

Projects General Guidance
1

Hello!
This is my first time posting on the forum, so I hope asking my question in this section is appropriate.

let me tell you a bit about me and what I need to do:

My education background is Biology and Pharmacotherapy, I never thought I would ever end up needing to assemble electronics or to program an Arduino board!

I recently joined a research project that involves taking pictures of samples from different angles, this is done manually now with an app that is installed on an android device. it is extremely inefficient and time consuming. I started looking for a solution to try and automate things, I found a really nice project that would speed up things a lot in theory. it is an Arduino controlled product photography turntable
( "Linked Here" )

it is exactly what I need with one important exception.
I have to use a smartphone camera, I can't use anything else, as the camera app is configured for our purposes so I have no other choice.
The project I linked above is using a DSLR and IR LED to trigger it, and this is the part I have to reconfigure in order to be able to use this setup with the smartphone camera.

apart from using the touchscreen the easiest way to trigger the smartphone shutter remotely in our current setup is by pressing the volume button on a headphone cable connected to the 3.5mm jack.

My question is how do I modify the turntable controller linked above to simulate the volume button press instead of the IR signal?
I am hoping this could be done, as one would think simulating a volume button press shouldn't be very challenging, but if I knew the answer I wouldn't be asking here!...

Everything is completely new to me and I'm learning as I go, I just need to find if it can be done and how, before investing into the tools and parts.

They say necessity is the mother of invention. I doubt I will ever invent something but I am willing to try and learn.

I'd appreciate it if you could give me some advice.

2

Replace the IR led with either a logic-level small-signal mosfet or an optocoupler. Hack one of those headphone cables to get access to the switch and rewire it to mosfet/optocoupler. Replace the bit in the code where the IR signal is sent with a simple pulse given to the mosfet/optocoupler.

That's the gist of it. Schematics are available if you search this forum a bit, because the question "how do I replace a button on device X with an Arduino" pops up once or twice every week here. Component choice is also discussed here and there.

3

Thank you very much for your reply.
How easy/difficult is it?
I am a novice so I don't have a clue about any of these things, I will try to search and learn more about the things you mentioned.
I hope I can pull it off somehow!

4

Not insanely complicated, but if you have zero experience with this, anything is hard of course :wink: It's something you can probably pull through with a little bit of help from the people on here. Your educational background suggests the grey part between year ears is sufficiently developed to wrap itself around this kind of stuff :wink:

7

Another option would be to use a small hobby servo to mechanically press the switch.

8

My thoughts as well, especially for somebody new to all this. Much easier to run the servo which will physically press the button

9

Which is easier depends a lot on personal preferences and capabilities, IMO. For me it's a lot easier to solve something electrically since I'm a big oof when it comes to fine mechanics.

10

It’s possible but kinda crampy to open up and hack a volume button on the headphones.

I made something similar by hacking a cheap bluetooth remote camera shutter device.

It was the same technique - many ways to take over a simple switch - but easier because the bluetooth shutter thing was huge by comparison, easy to get into and less likely to be broken doing.

https://www.amazon.com/Wireless-Bluetooth-Smartphone-Compatible-Cellphone/dp/B073VSVTQF

Side benefit - since the headphones aren’t plugged in, you can hear the shutter sound…

a7

11

Depends - do they need to neatly close back after the hack? :wink:

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