This past halloween, my wife and I decided to dress up as mortal enemies: a Dalek and the 10th Doctor from Doctor Who. Obviously in order to be even remotely frightening to a figure as historically headstrong as the Doctor, she was going to need a good headpiece.
Wearability was the key factor here so while I aimed for a bit of authenticity in the embellishments, the dimensions and such were adjusted so that it wasn't horribly uncomfortable to wear for hours at a time.
Step 1: Find a Helmet, Cut It Apart, and Bore the Necessary Holes
The first step was to find an appropriate base for the Dalek dome. Amazon Prime was once again my go-to; I quickly found a nice black hard hat that had comfortable four-point suspension which served the dual-purpose of giving me some space on the inside to work with.
I first cut the brim off with a jig saw, which was quick and relatively painless despite a little bit of difficulty cutting at a very irregular angle. The hole for the eye stalk was made with a spade bit, and the holes for the dome lights were added in the same way. My plastic dome light lenses were fabricated with a flat bottom, so I also used a belt sander to flatten an area for these to attach.
Step 2: Creating the Eyestalk: Lighting
Creating my Dalek eye stalk was a multiple step procedure involving electronics, 3-D printing, laser cutting, welding, and drilling.
The first step was to find the right materials to make the signature blue eye light and figure out where to stash the drive electronics. From a previous project, I had a rod of Acrylite Endlighten which I figured may fit the bill perfectly. When you shine light in the end of this material, it glows throughout all of its' surfaces. Pictured above is a test of the material with a royal blue LumiLed and a BuckToot driver. The BuckToot is a tiny 1W constant current LED driver that has a wide input voltage range- perfect for my 2S lithium battery pack I purchased to run the Dalek dome.
Step 3: Creating the Eyestalk: 3-D Printed Pieces
Using Fusion 360, I designed the end piece for the Dalek eyestalk based on the 2005 Dalek redesign. When printed, it would slip perfectly over the end of the Endlighten rod. Additionally I made a recess in the front piece that would hold and center an LED lens glued inside to give the "eyeball" the right look as shown in the second and third pictures.
After the eye cup was printed, I modeled the cowl for the front of the dome. This piece was also based loosely on the 2005 Dalek Sec, and in addition to being decorative also would cover up the screws/mounting of the eyestalk to the hard hat.
Step 4: Creating the Eyestalk: Laser Cut Pieces
Next up was the eyedisk group, which I cut out of 1/8" clear acrylic. After figuring out the proper inner diameter to slip snugly onto the Endlighten rod, I cut a series of disks and spacers and pushed them into place. These also glowed nicely when the light was applied to the end of the rod.
Step 5: Mounting the Eyestalk to the Dome
This step was a little harder than originally anticipated. I needed a good solid attachment to an otherwise flimsy HDPE hard hat that could hold the weight of the eyestalk cantilevered out in front. To accomplish this, I decided to make a two piece metal mount that would sandwich the hard hat in the middle. That way any torque on the plastic generated by quick head motions would be spread out over a larger are on the front of the hard hat.
After a quick trip to the hardware store, I found two fender washers that had a large enough ID for the Endlighten rod to pass through. When paired with an offcut from a piece of steel tube, I had the makings of an eyestalk mount.
I cut the steel tube to length on the cold saw and welded it to the fender washer at the proper angle. Since these were galvanized washers, I made sure to grind the zinc coating off on the bench grinder to avoid making noxious and dangerous fumes when welding it together.
After test fitting the first one, it became obvious that the angle of the hard hat was not going to allow a flush fit of my sandwich concept, but the plastic seemed plenty strong with just thru-bolting of the metal piece. Also, I remade the metal mount using only butt welds on the back to help bring the mounting plate closer to the hard hat when pushed through as in the third picture.
Step 6: Making the Dome Lights
After the eyestalk was complete, I started on the dome lights. Amazon Prime delivered these awesome 7oz. plastic cups which are completely adequate replacements for the no longer made (and expensive) Moflash lenses that were used on the TV show Daleks. The lip was easily removed using the vertical band saw, making these ready for fitting in a cage.
I took to CorelDraw to CAD up the parts of the cage and laser cut them out of 1/8" acrylic. Originally these were aluminium, and I considered cutting them on the waterjet and TIG welding them but that seemed like too much of a hassle when acrylic is so easy to work with.
After test fitting and filing down the parts, I sprayed them a pearlescent silver and CA glued them together.
Step 7: Lighting and Programming
I had already decided on using a compact 2S (7.4V) lithium battery pack to drive the lighting, and had two BuckToot drivers to run the LEDs. So in order to control the intensity and add the blinking to the dome lights, I laid out a quick circuit on breadboard consisting of a few power transistors and a Teensy. Originally I had a small condenser mic board in there also to control the blinking of the top lights with speech, but background noises meant that they lights spend more time solidly on than actually blinking so I scrapped it and just programmed in a random pattern.
The Teensy code drove a PWM signal to the base of the TIP transistors which in turn powered the BuckToot drivers. This let me dim the front blue LED (it was really bright pointing into people's faces), and make a nice fast fade-in/fade-out for the top dome lights which gave them more of an incandescent appearance.
Step 8: Mounting All of the Electronics
The original idea was to hollow out an area in the front of the hat and place the battery in a recess modeled into the cowl (first picture), but it turns out there was enough clearance under the suspension of the hard hat to just stick it up on the inside. The LEDs were all mounted to thin metal with thermal adhesive for heatsinking (although at the low duty cycles I was using they didn't heat up appreciably), and these were attached to the inside of the hard hat with VHB. I left the Teensy in a position where I could get to it for programming if necessary, and the battery where I could get to the JST connector for recharging.
Step 9: Attaching the Cowl and Dome Lights
HDPE, from which this hard hat is manufactured, is incredibly slick. Normal adhesives won't work on it, and most glues that do work on it don't really jive with other types of plastic. Since VHB is actually made for mostly permanent bonding, I decided to go ahead and use it to stick these pieces to the hard hat. The flat bottom of the dome light discs were adhered to the sanded flat sections of the dome, and the cowl was pushed over the steel tube and adhered in place. Finally I placed the eyestalk into the metal tube and secured it with a dab of hot glue.
Step 10: Final Product and Testing
The Dalek Dome headpiece accomplished everything I had planned- daylight visible lighting, looking good, and being somewhat comfortable to wear.
Here's pictures of a Dalek Ikea crab, my wife and I battling for the fate of the universe, and a short video clip showing the lighting in action!