UPDATED 5/9/16 Made flashlight cup a bit thicker due to a think wall UPDATED 5/21/15 Added a revised version of the "flashlight cup" for cosmetic reasons. This is a 3D printed microcontrolled multiple mode flashlight that I designed for my Circuits 2 students to program and assemble in class. Please print all the parts on your favorite 3D printer. I Included all the original AutoDesk Inventor part files so you may modify the parts to meet your needs. You may need to generate support material to make the lens ring print cleanly. I soldered everything together dead bug style to save time and space. I used hot glue to hold and protect the circuit. You may use any LED you like. I used six 5mm Super Bright Wide Angle LED's. You will need to print and add a wire to the battery slug to install in the 4AA pack to bypass one cell making the pack 4.5v. DO NOT RUN 6V INTO ATTINY85 !!! IT WILL BURN OUT !!! The Arduino sketch is also attached. You may add as many modes to the flashlight as there is room in memory on the Attiny85. This circuit draws about 45ma while operating and depending on the quality of batteries and the LED's you installed, you should expect about 100 hours of burn time before the batteries need to be replaced. *When installing the battery pack, I left a ridge out of the center of the handle so that the battery terminals don't interfere. Be sure to inspect the inside for the missing ridge so that the battery pack full seats and the strap will just rub the bottom of the pack making it a snug fit without any slop. *The battery strap slides into the bottom from the side in order to keep the battery pack in place. It is designed to be very tight and may need some convincing to get it to slide in properly. *When installing the push button and switch, solder the wire on first and then press into place. Depending on the quality of the print job and exact switch you purchase, you man need to ream the holes out a little bit with an exacto knife to make them fit properly. Feel free to leave any questions or comments. http://amzn.com/B0056F5D4M - Rocker Switch Used http://amzn.com/B00E1JN6SE - Button Used http://amzn.com/B00FIVZUW4 - Attiny85 Used http://highlowtech.org/?p=1695 - How to program Attiny85 with an Arduino http://123d.circuits.io/circuits/789275-sehs-flashlight-v2 - Custom PCB for this project. ( not sure if board fits in current design, update to follow )