What you're buying
A DIY module is the camera, the recording board and the lens, with no case. That is the point: a ready-made disguise only fits the room it was designed for, while a module can go into a piece of furniture, a vent, an appliance or anything else that already belongs where you need the view.
Three things to check before ordering. The lens type decides the field of view and how small the opening can be. The power arrangement decides whether you need a battery pack or can wire it to an existing supply. The storage decides how long it records before overwriting.
Related
If you would rather not build anything, the same cameras come ready-housed as hidden cameras, or in the smallest complete bodies as mini spy cameras.
Common questions
How much work is it? Most installs need a hole for the lens and a way to power the board. No soldering on the majority of modules.
How big is the lens opening? Pinhole lenses need only a few millimetres, which is why they can hide in a seam or a screw hole.