Back to the Future : Flux Capacitor

Ever since I first saw the Back to the Future trilogy, I was amazed at the gadgets that were used. One that always struck me as fascinating was Doc Brown's invention of the Flux Capacitor. I always wanted to build a replica of the flux capacitor and this Back to the Future Contest was a perfect reason to do so.

My aim was to create a replica as realistic as possible while keeping the cost relatively low and for the build to have some functionality aswell. For the cost part, I chose to make my own case using plexiglass. Granted it wont make for a perfect replica but it will be close. As far as the functionality is concerned, I added LED's to the build hence it can act as a perfect night light.

So lets get started, shall we.

Materials Required

1. Plexiglass Sheet (Clear and Any other color)
2. Silver and Black Spray Paint
3. Halogen Rod Style Bulbs
4. Plastic Pipe
5. Yellow + Red Paint
6. Small Corner Brackets
7. Screws and Nuts
8. Blue Leds
9. Resistors 220 Ohm
10. Wire
11. Perfboard
12. DC Jack
13. Switch
14. Aluminum Tape
15. Spray Bottle Covers

Tools Required

1. Plexiglass Cutting Tool
2. Ruler
3. Hot Glue
4. Tape
5. Drill
6. File
7. Cutter

We will begin by constructing the case for our flux capacitor. The dimensions i have chosen are 12" x 14" x 4". For the construction first we need to score 'n' snap the sides of our box.

Two 14" x 12" pieces (One of them will be of clear plexiglass)

Two 14" x 4" pieces

Two 12" x 4" pieces

We also need one more piece to place inside this box but more on that later. What you will do is to remove the protective paper from one side of all the sheets. Then keeping that side inwards, use tape to dry fit together all the pieces to form an open box. Check the fitting and file where required to get it to fit correctly. The use hot glue and apply it along the inside edges. Now the box is secure.

Now on to the brackets. Remove protective paper from all four bottom sides. Place the corner brackets and mark the spot to drill. Drill it and then secure the brackets using nuts and bolts. Now to the top side. Place the clear plexiglass piece on top but don't glue it. Place the brackets and mark the holes. Remove the top piece and secure two of the brackets. Leave the other two. The top piece should slide in the brackets and the using the remaining two, secured into place. Check to ensure proper fitting and sand where required. Once done, remove the top piece.

Before we move on to spraying, we need to prepare the top piece. For that mark a two inch border on both sides and score a cut along the inner rectangle. Remove the protective paper from both sides. along the outer edges as to leave a rectangle in between. Clean all the parts free from debris.

Finally spray the main case, the top and the two removed brackets. Apply a thin coat and allow to dry. Do it in a well ventilated area. Once it dried apply a second coat. Now the case is done so we will move on to the innards.

For the inner piece, measure the internal measurements of the case and then cut the internal piece a little smaller than the actual dimensions. Make sure it fits. Then spray paint it black.

For the base what i did was that i removed the two nuts from the top two brackets. I added two extra nuts in them to make them protrude. It made the case stand up, leaning backward a bit. It gave a nice display to it.

For the stands i used three spray can covers since i could not find anything else. I used aluminum tape to give them the metallic finish. I covered all three with aluminum tape on the outside and then smoothed it out using my fingers. Then using a mixture of silver and black acrylic paint, i gave a nice rustic look to it by sponge painting using a tissue paper. For that just mix the paint and use a tissue paper to apply it without use of water.

The next step is to mount the glass rods on the stands. First i carefully removed the ceramic ends of the halogen rods. Next I placed the rod on the stand and drilled small holes through which i can run wire. I made a total of four holes. Then i used thin blue wire to secure the rods such that the end of the rod is in the center of the stand. Do that to all three stands.

The electronics is very simple. Just three led's with a 220 ohm resistor and a switch. I soldered long wires to each led. Then I constructed a small circuit on a piece of perf board. I mounted a DC jack, a switch and the three resistors. Secured the led wires and then tested to see if everything works fine. Once it is tested, we can move on.

Now we need to measure and mark the position of the stands on the black base board. It may vary for you but what i did was mark the upper two, equidistant from the sides. Then i placed the third such that the rods converge uniformly and mark the spots of all three. Basically it should look neat and uniform.

Nest drill holes roughly in the centre of the marked spots for the stands to run the led wires. Alse drill holes on the side of the stands. This is so that that the wire is exposed partially giving a tech type feel. Run the led from beneath the base board and from under the stands and into the side hole, going on top. Use hot glue to secure the led in place facing towards the end of the rod. Use aluminum tape to hide the holes.

Hot glue the three stands in their marked place.

Well the wires in the actual prop are going to be replaced by a pipe. Because a pipe is cheap and easily manipulated. So we will measure and cut two 7" pieces and one 5" piece. Using a flame, bend the pipe so that it forms the shape as shown.

Then we need to cut groves in the upper ends so that the pipe will fit on top of the led and rod end. Two of the longer pipes will get diagonal cut and the shorter one will get a straight cut.

Then we will paint them yellow. Paint two coats of bright acrylic paint. Paint the end red to depict the cover that i couldn't find any where in the market.

Using hot glue, glue the pipes as shown. First the top and then to the base.

Now we move into the final assembly stage. First we need to make and make a slot on the side for the dc jack and switch. Drill holes on the perf board and assemble it such that they protrude out. Be care full not to nudge the wires so hard as to break them. Then using some spacers, secure the base board inside the case. I used pieces of the pipe as spacers and glues the base board in place.

Now all that is left is to use a blower to clean the inside and place the top cover on. Clean the top cover using a cloth. Secure the ends with the angle brackets. And you are done.

Despite the variation in design from the original movie prop, I am still very happy with the build. The blue light gives a special effect and it is a wonderful decoration piece and a conversation starter.

If you found my instructable up to the mark, please vote for me in the Back to the Future Contest. I will be very grateful and promise to continue bringing more ibles.