Back to the Future: Doc Brown's Mind Reading Helmet

I love the Back to the Future series. It was definitely a staple growing up, and for Halloween I wanted a costume based on it.

Now, I'm no Marty McFly, I'm definitely more the Doc Brown type. I don't look anything like him, but with some awesome headgear, I knew I'd be set!

Step 1: Gather Materials

For this project, I used:

an old bike helmet
a length of 5/8" dowel
some conduit grommets that (almost) matched the dowel
reflectors and stands from some solar garden lights
some old solid (non-braided) wire
a switch
a 9-volt battery
one resistor
a bunch of yellow-orange LEDs
some speaker wire
a bit of sheet metal
black, grey, and copper spraypaint
leftover cardboard from cereal boxes
a few cardboard toilet paper tubes
some random screws

This was one of those nice projects I like doing where I was able to repurpose nearly everything I needed from something I already had lying aroudn the shop. the only things I had to buy were the helmet and the conduit grommets.

Step 2: Prep the Helmet and Add Sheet Metal

First off, clean all that garbage off the helmet! I had to take out the foam comfort strips too because I have a giant freak head.

Next, cut a strip of sheet metal about 1 or 1-1/2" wide. I used a hack saw and my miter box to keep it uniform.

Make an X across the top, and then wrap the whole base of the helmet. My usual procedure of tacking it in place with hot glue, followed by overnight with epoxy worked beautifully.

Step 3: Drill Holes and Add Conduit Grommets

The LED assemblies are attached to the helmet itself via lengths of dowel, recessed into the helmet. I used thirteen LED assemblies, one at the top, eight in a circle around the base of the helmet, and four in a circle halfway between.

First I drilled small pilot holes, then took the whole thing to the machine shop at work after hours, and used a large drill bit on the drill press to make holes that were just right for the conduit grommets.

The process of drilling these large holes kind of tore up some of the sheet metal and parts of the plastic helmet, but I was able to glue/epoxy everything back in place, and the grommets covered up most of the problem areas.

Step 4: Prep and Add Dowels

The dowels were cut to a uniform 2-1/2" using my miter box. They were just a bit loose in the conduit grommets, so I added a couple of loops of electrical tape to the end of each. Finally, I put them in place and secured them all with epoxy.

Step 5: Cardboard Washers

Using the toilet paper roll as the outside diameter and the plastic tube from a garden light as the inside diameter, I cut out several cardboard washers.

Step 6: Toilet Paper Tubes

Again using the miter box for uniformity, I cut off about an inch or so from thirteen cardboard toilet paper tubes. This gave me thirteen long and thirteen short, uniform tubes.

Each of the smaller tubes had one of the cardboard washers glued to it. These were all painted primer gray.

Finally, I added two small screws to each of the washers.

Step 7: Plastic Tubes

The plastic tubes harvested from old solar garden lights would serve as the base of each LED housing. I cut each to length using the miter box, then painted them all a coppery color.

Step 8: Wire Stars

I needed a four pointed wire star at the top of each LED housing, both for accuracy and for stability. Using a piece of scrap wood and some finishing nails, I built a simple jig, wrapped my solid core wire around it, and then cut them off. I added a dollop of hot glue to the spot I'd cut each star to hold it in one piece.

All the stars were then spray painted black.

Step 9: Building the Housings

Each LED housing started with the reflector pressed into the painted tubing. Next I would attach the wire star with little dabs of hot glue, followed by the larger gray cardboard tubes, also attached to the wire star by hot glue. Last came the LED itself, with legs bent at 180 degrees and hot glued in place, emitter pointed down at the reflector. When it was all done, I put a bit of epoxy over each hot glue joint for a more permanent bond.

Step 10: Add the Housings to the Helmet

Each of the short cardboard assemblies is now placed over the dowel, followed by the housing tube. Hot glue to hold it, then epoxy to make it permanent.

Step 11: Crossbeams

Using strips of cardboard painted primer gray, I cut each crossbeam individually, then hot glued it in place. Time would prove these to be the most easily damaged parts of the helmet, I had to reglue several of them.

Step 12: Wire It for Power

The LEDs in this assembly are wired in parallel, with a single resistor in series. I played around with the resistance until I found one that gave me the brightness I wanted.

Each LED is wired up to the main switch and a 9-volt battery located at the back of the helmet. I wasn't too careful about where the wires lay, as the original had a cobbled together prototype look, particularly where the wires were concerned.

*** Note--take a look at the comments, ElectroFrank has made some interesting points about how to PROPERLY wire this sort of simple circuit for a more efficient use of the batteries involved. ***