Tiny Flashlight with Customizable Diffuser

This tiny flashlight consist of just a 3v coin battery (type 2016) and a standard T1 ¾ LED. The clip-on hood is used to hold customizable diffuser discs. It even has a tiny on-off switch.

The 25mm diameter hood will accept any disc you want to create as a diffuser. Use a simple silhouette or get fancy and create a lithopane. You can easily design one up in something like Tinkercad and then 3D print it, or even just cut ones out of paper.  The disc should be 24.9mm diameter to get a good fit, and pretty much any thickness. I've included 3 different diffusers (Christmas tree, snowman, radial spokes) to get you started.

Printing
I printed this in PLA using 0.2mm layers. No supports, brims or rafts are needed.

Assembly
You will need one T1 ¾ LED and one type 2016 coin battery. I used some random red and green LEDs I had lying around, but for a brighter light, I'd suggest using these high intensity white LEDs: CREE part number C503D-WAN-CCBEB231

The LED leads will need to be cut and bent as shown in the 4th photo. The longer lead (the anode) should be cut to 12mm long and then formed as shown. The shorter lead, the cathode, should be cut to a little less than 8mm long and also formed. When the battery is placed in the tray (+ side down), slide the LED over the edge of the battery as shown in the last photo. It should light up. The shorter lead will overlap the top side of the battery by about 2mm.

With the LED glowing in place, shove the tray into the body all the way so that the LED pokes out the hole in the other end. The LED should press into place, so that when you slide the tray back out to the “off” position, the LED stays in the hole. If the LED pulls back out with the battery tray, shove it back in and apply a tiny dot of superglue to the edge of the LED to hold it in.

The little nub on the side of the tray is your on-off switch. Push the tray all the way in to turn on the light, pull it back a notch to turn it off. Or you can pull the tray all the way out to change the battery.

Finally, the hood just slips over the end of the flashlight with the notch in the hood aligning with the little flexing arm on the side of the body. The diffusers just press into the front-end of the hood.