MN has been working on the Arduino based prototype, that was initiatily supposed to cost less than $20 and be composed of these components:
The camera we've been using:
By fiddling with some keychain camera variants, however, MN discovered that the cheap versions of the keychain camera are dealing very poorly with sleep-wake cycles, i.e. to save the battery* they need to be programmed to fall asleep, and waking up, in the end, takes at least 4 sec. Needless to say that is waaaay to much for trying to observe wildlife.
MN will share the code & more details about this keychain based prototype soon.
However, we have now dropped the keychain camera idea & moved on to a bit more expensive, yet more standard & accessible solution (especially for people with less electronics & programming expertise), including an Arducam.
We think it will be a lot easier to accomplish quick reaction times with an Arducam, without using up too much battery. Only catch - ~$10 increased camera trap price, although we think it would still be doable under $30.
Our ordered Arducam just arrived, and we will report soon!
* one of the goals, that also emerged in collaboration with MammalWeb.org (see our collaboration notes here), is to have the trap active in the field for a month or even longer at a time, while using standard (e.g. AA bateries). That requires a very energy-efficient solution.