Step 1: Sourcing Parts
To build your own desktop UFO, you'll need the following parts:
- 2 x metal candle holders (I found mine at Walmart for $3 a piece.)
- 1 x glass dome shaped candle holder
- 10 x LEDs (2.4V or less)
- 2 x IC PC Boards
- 1 x 4017B decade counter
- 1 x 555 timer
- 1 x 1k potentiometer
- 2 x 1K resistors
- 1 x 10uf capacitor
- 2 x 1uf capacitor
- 1 x 9V battery
- 1 x SPST switch
- 2 x 10-24 x 2" Flat Philips Machine Bolts
- 4 x 10-24 nuts
- 2 x lock washers
- Soldering iron
- Hot Glue Gun
- Drill (a benchtop drill press works the best)
- 3/8" clear tubing
- Most important: patience
I bought 2 of each body component and 10 times each electronic component. The main reason is that I really didn't have a good handle on how everything would fit together. Having extra parts allowed me to experiment with a prototype.
Step 2: Body Work
The first step was to remove the feet from one of the metal candle holders. On my first time through, I tried using a hammer and a Dremel saw, both of which messed up the surface of the metal. In the end, I opted for a simple solution: simply attaching vice grips and torquing the feet off. No mess.
Next, I taped the two metal pieces together and marked the holes for the bolts that would hold the body together. Using a 1/4" drill bit in my press, I drilled two holes all the way through both plates.
On my prototype, I used metallic paint to color the top gray. I didn't like the way it came out so I used a belt sander to remove all of the black paint from the top.
I drilled one 7/32" hole in the top for the switch and one 1/4" hole in the bottom for the potentiometer. The switch comes with a bolt and lock washer -- the POT I attached with hot glue.
3/8" plastic tubing provided the perfect spacing and obfuscation for the components inside. I glued this down with hot glue.
I then threaded two bolts through the top (sanded) plate and added lock washers and bolts on the inside. Because they stuck out too far on the bottom, I cut them down with my Dremel.
Step 3: Electronics
I have to say that this was one of the hardest parts of this project. I dabble in electronics, mostly with an Arduino and this was my first foray into the world of IC's. I found some great resources online for LED chaser circuits and my friend Trent helped me to order the parts from Digikey.
Once I received the parts, I built the circuit on a breadboard to ensure that I understood how it worked and to test it. The biggest problem I had was that the breadboard had some bad connections which caused the circuit to work sometimes and other times flake out. For a novice, this made it really difficult to troubleshoot. Trent (who does this stuff for a living) helped me tremendously!
Once I had the circuit working well on the breadboard, I began to transfer it to the two small IC boards I purchased from Radio Shack. I used small braided wire to complete each connection. It's important to draw this out on paper first as it's easy to get lost while wiring. This process took me about 3 days. Once I had the two boards wired, I got to work attaching the LEDs to the base.
I glued each LED down with hot glue and soldered all of the (-) legs together. From the last (-) leg, I ran a wire to the decade counter board. Then I soldered a 4" wire to each (+) lead and added shrink tubing to ensure the leads didn't short. Additionally, I added electrical tape to the bottom of the metal plate and backs of the IC boards. I then wired each LED into the corresponding pin on the decade counter.
I'm embarrassed to show the backs of the IC boards -- being a novice, I used entirely too much solder.
Once I had everything together, I plugged the battery in, hit the switch and...nothing. Frustrated, I went back to the schematic and started checking my connections. I found two that I missed, re-soldered and then hit the switch. It worked!
Step 4: Finishing Touches
With everything tested and working, I then crammed all of the wires back into the body, lining up the holes on the bottom plate, and threaded nuts onto the two bolts. For the top, I added some VCR parts and a gear and attached the glass with silicone caulk.
Though I'm happy with the result, I've already started thinking about improvements to the design. I'd like to add and LED inside the cockpit and holes in the top and bottom (above and below the LED's) so you can see the entire light rotation.
If you do build your own UFO, please post pictures in the comments!