Skateboard With PIC Microcontroller and LEDs

What do you get when an Electrical Engineer builds a Skateboard from scratch for a 13 year old's Christmas present? You get a skateboard with eight white LEDs (headlights), eight red LEDs (tailights) all controlled via PIC microntroller! And I might add, one very happy 13 year old, well as happy as a 13 year old can be. Following is how I modified a skateboard kit (from ROAROCKIT.COM), added LEDs to the front and back, added PIC circuit, and covered with a comic book and custom graphics.

Step 1: Start Building the Skateboard

Starting with a laminate kit that was purchased from www.roarockit.com, laminate the first three layers together. The laminate kit from roarockit includes everything needed to laminate and form your own skateboard. This is the second kit that I have used from them and have been very happy with their product.
1. Place the first laminate on the foam mold.
2. Spread the skateboard glue on the first layer.
3. Place the second laminate on top of the first.
4. Spread the skateboard glue on the second layer.
5. Place the third laminate on top of the second.
6. Insert guide pin.
7. Slide the assembly into the netting.
8. Slide the assembly into the vacuum bag, seal the bag, and pump out all the air.

Step 2: Create Channel for Wires

The wires that connect the LEDs at the front and the back of the Skateboard to the circuit board are installed in the fourth (middle) laminate of the skateboard.
1. After 24 hours remove the first three laminates from the vacuum bag.
2. Cut a channel/groove into the fourth laminate.
3. Add glue to the top of the first three laminate.
4. Place the fourth laminate on top of the assemble.
5. Place the assembly onto the foam mold, insert guide pin.
6. Place the entire assembly into the netting, then vacuum bag, and vacuum all the air out again.

Step 3: Add Wires and Complete Skateboard Assembly

Since we are using eight LEDs at the front and back of the skateboard in a common anode configuration, we need nine wires from the circuit board to the front, and another nine wires from the circuit board to the back. I cut the wires out of a serial cable so that I would have eight different colors. The ninth wire is a larger gauge wire. With this combination I did not have to mark each individual wire.
1. After another 24 hours remove the assembly from the bag.
2. Tape/clamp the remaining three laminates together.
3. Drill holes in the last three laminates at the location of the LEDs and circuit board. Note: I used the TLAR (that looks about right) method for locating the holes.
4. Tape the wires into the groove.
5. Glue and add the last three laminates to the assembly, while pulling the wires through the holes that were drilled.
6. Slide into netting and vacuum bag for the last time.

Step 4: Build the Circuit

This circuit is based on a PIC16F870 microcontroller. This controller was chosen because of the number of input/output pins, and the fact that I have a programmer for this chip. The input is a single pushbutton that cycles through each of the 15 LED flashing patterns. The outputs drive transistor switches, which turn on the individual LEDs. The transistor switches were used to keep the power dissipation through the microcontroller under the specified maximum (200 mA max). The power supply for the circuit is a slightly modified LM317 kit that is available at Ramsey Kits. The power supply was chosen because the circuit will be potted (encased in potting epoxy) and the LM317 will not require a heatsink. The kit provided a ready made circuit board and parts to construct the power supply, DC input is provided by six AAA batteries (9 volts). Since the kit is designed to accept AC power input, I removed the Diode bridge rectifier and large cap as my input is already DC. The power output was adjusted to achieve 5 volts for the microcontroller and the full 9 volts are used to power the LEDs. The entire circuit was tested on a bread board, then built on a prototype board from radio shack. The parts list can be derived from the schematic. The assembly code and video of testing are also attached.

Edited: Here is the YouTube video:

Step 5: Build Housings

The LED housings are carved out of Balsa, reinforced with fiberglass and 60 minute epoxy then blended into the board using Bondo (plastic body filler). The housing for the circuit board is created using a project box from Radio Shack, cut to conform to the curves of the board then attached using epoxy and fiberglass. The project box is also blended to the board using Bondo. The LED mounts at the front and back are made out of Aluminum strips from Home Depot, that are drilled to accept the LEDs. The circuit board was constructed first so that the height of the project box could be determined, again using the TLAR method.

Step 6: Adding the Artwork

This step was easily the most labor intensive and time consuming. I have been told by everyone that has seen the board that the pictures I sent them really don't do the final product justice. The skateboard is covered with pages from a comic book and artwork created with Photoshop and Corel Draw printed out on sticker paper. Note: I tried several different papers for Ink Jet printing for the artwork. The one that I had the best luck with was full page labels from Office Depot. All artwork was attached using Polycrilic from Home Depot, then an additional 15-18 layers of Polycrilic were added. Finally the board was sealed with an Acrylic Sealer from Hobby Lobby and Tread Tex from Ace Hardware was added to provide grip. Below is step by step of how it was done.

1. Cut the comic book pages into manageable sections.
2. Soak the sections in Polycrilic.
3. Apply to the board using a flexible plastic spreader.
4. Wait two hours then apply the Ink Jet Stickers. Stickers are sealed with Acrlyic sealer before Poly is added.
5. Apply coat of Polycrilic.
6. Wait two hours then sand the Poly with 220 grit sand paper.
7. Repeat steps 5 and 6 until you can no longer feel the edges of the paper. Note: In several places I sanded through the Poly and damaged the comics/art, this "accident" added character to the board and if I did it again I would not avoid sanding through.
8. Once the edges could no longer be felt, I switched to 320 grit sand paper, then added two more layers of Poly.
9. A wet layer of Poly was added to the top of the board, Tread Tex was sprinkled onto the board using a salt shaker.
10. Two more layers of Poly were added to the top of the Tread Tex.
11. The entire board was sprayed with a clear gloss Acrylic sealer.

This entire process took almost two weeks.

Step 7: Make LED Assemblies

In step five we drilled the Aluminum strips for the LEDs, here we add the LEDs to the strips and prepare them for inserting into the skateboard.

1. Insert eight white LEDs into one strip, attach using 5 minute epoxy.
2. Solder all anodes together.
3. Repeat steps one and two with the red LEDs.

Step 8: Putting It All Together

In this step we complete the assembly of the Skateboard.

1. Solder the LEDs to the wires that are sticking out of the housings. Make a note of what color wires goes to what LED.
2. Attach the wires to the circuit board.
3. Install batteries and test the circuit before gluing anything permanent.
4. Glue the LED assemblies to the housings.
5. Glue the battery boxes to the skateboard.
6. Drill holes for the switches and install the switches.
7. Create a barrier between the circuit board and batteries.
8. Mix and pour the potting epoxy.
9. Drill the holes for the trucks.
10. Install the trucks and wheels.
11. Ride and enjoy.

Edited: here is the YouTube video:

Attached is a short video of Josh (the 13 year old) riding the board in the dark. The video was hard to shoot in the dark with the bright LEDs, but Josh claims they make it much easier to ride at night.