Summary

I like this design (https://www.thingiverse.com/thing:1275111) but the fitting was a bit small for my laser diode and flimsy, and since I had these battery contacts I decided to make a beefier version with slots for the contacts

A remix of https://www.thingiverse.com/thing:1275111

1 650nm 5mW 3-5V Module Diode w/ driver (cylinder housing is 12mm)
1 momentary push button switch (7mm)
2 positive battery spring contacts (suitable for AA and AAA batteries)
3 LR44 / AG13 batteries