Ultracapacitor 3d Printed Flashlight

Using available parts and a 3d printer, I went from idea stage (sketch above) to a working device in one day. 

Printing and designing in 3d allows a designer to build a case and mechanical parts around whatever is available.  For example, I used an ultracapacitor from a Coleman Ultracap Screwdriver.  It was simple to design and print a hollow cylinder to accept the capacitor--this would have been a major challenge a year ago.

Step 1:

First I printed a cylinder, scavenged the capacitor and found an LED.

I used Autodesk 123d (free) to design the 3d parts. Files are available here:

http://www.thingiverse.com/thing:31650

Step 2:

Next, I came up with a plan.  The LED is pretty directional, so I skipped building a reflector.  The light will run for hours and hours on a charge (and I charge it with a solar panel), so I omitted the on/off switch. Note the diode--that prevents the capacitor voltage from going backwards out onto the leads; you can clip the alligator leads together if you want after charging.

If you want to see how I regulate the incoming voltage, look at this instructable:

https://www.instructables.com/id/Solar-Powered-LEDUltracapacitor-Arduino-Regulated/

Step 3:

Check to see that the capacitor fits into the cylinder.

Step 4:

Drill a 1/8 inch diameter hole in the upper part of the cylinder (yes, I should have designed that in software, but I'm far from perfect).

Step 5:

Slide the capacitor (minus any wires) into the cylinder.

Step 6:

Add a 100 ohm resistor to the long lead of the LED (I soldered it).

Step 7:

Add a red wire wrap wire to the other end of the resistor.

Step 8:

Clip the surplus wire from the resistor and put a piece of heat shrinkable tubing over the exposed metal.

Step 9:

Heat the tubing until it shrinks (I use the soldering iron to shrink the tube).

Step 10:

Add blue wire wrap wire to the short leg of the LED.

Step 11:

Clip the excess LED leg, add heat shrink and shrink the tubing.

Step 12:

Push the wire end of the alligator clips through the hole in the cylinder.

Step 13:

Push the LED leads through the cap (it's not really a reflector).

Step 14:

Connect the red LED lead to the red alligator clip.

Step 15:

Connect the diode (end without the band) and blue LED lead to the negative post on the capacitor (there's a big "-" next to the post on this particular unit).

Step 16:

Connect the black alligator clip wire to the band end of the diode.

Step 17:

Connect the red LED/alligator wire to the positive side of the ultracapacitor.

Step 18:

Test the flashlight--it's easier to correct problems now--before it's closed up.

Step 19:

Use aluminum duct tape to fasten the top cap to the cylinder--this is easy to remove if you ever want to go inside.  You can use acetone or superglue to "weld" the parts together, but I prefer easy access in case I want to go inside.

Step 20:

I'm looking at it now, 5 hours after assembly--and it's still shining brightly with no indication of decreased light.