Came recently across a fairly old (2013) thread on this forum:

https://www.largeformatphotography.i...for-the-iPhone

So I downloaded the Android version:

https://www.filmomat.eu/photoplug

Although the app is relatively old, and could be improved, it basically works quite nice in audio mode for speeds up to 1/30. And it helps if you have a loud shutter.... Placing the shutter on a table, and the mic of your smartphone as close as possible, use a cable release & no other sounds.

Than I read about the Photoplug and I released that I had made something similar in the past (well an acquaintance did actually): a photo diode which plugs in a PC, and you can measure behind the shutter when having a light source on the other side, opening and closing gives you a wave form on an Audio program such as Audicity.

The scheme:
Click image for larger version.  Name: schaltklein.gif  Views: 22  Size: 2.5 KB  ID: 218588

It involves a AA battery of 1.5 Volt.

No my question is: can I plug in this sensor in my Android phone (the 2mm Jack Plug for headphones) ?

I am not very knowledgeable on electronics, and I wonder about the 1.5 volt battery could damage my phone ?

thanks in advance,

best,

Cor