Canon EOS M Battery Grip

This is probably not useful to anyone as-is, since it relies on custom electronics which you won't have. However it may be useful as a reference if you are considering doing something similar.

Watch a video about the project here:
https://www.youtube.com/watch?v=-LdBVMd4dAY

Read more detail here:
https://funkster.org/e/hack/hotswapgrip