HoverDisk

Hello Everyone! Would you like to build a HoverDisk?

HoverDisk you ask? That's correct! Well it really doesn't hover but it sure looks like it does. In honour of my favourite movie "Back to the Future", I thought I would build my own version of a hoverboard. This is a human transporter that is built from an old electric wheelchair, 2 Arduinos and some other miscellaneous parts and circuits. I hope you enjoy reading about this Instructable and maybe even building your own version.

There are many options to choose from as you build one of these. You could eliminate the lights and sound effects which would make for a more simpler project, and you could also hard-wire the remote on a tether instead of making it wireless.

This project would assume you are comfortable with using Arduino microprocessors and basic wiring. It will be helpful to also have access to a shop in order to cut some of the parts out of wood.

Please check out the video at the end of these steps to see it in action!!

Here are the parts you will need:

• 2 Arduinos
• 2 Xbees
• 1 Sabertooth Motor Controller
• 1 Latching Relay
• 1 Power Relay shield for an Arduino
• 1 AudioFX Soundboard
• 1 5 Volt Battery Pack
• 2 - 12v Batteries
• 2 Wheelchair Motors
• LED Light Strips
• 3/4 inch Plywood
• Miscellaneous Electronic Parts
• Paint

1. The first step is to remove the electric brake and associated brake wires from your wheelchair motors (if you are using a different type of motor then there probably isn't an electric brake). You can just cut these wires off.
2. I didn't want my HoverDisk to be too high off the ground so I removed the large wheelchair wheels and bought some new 8 inch lawnmower wheels.
3. I had to carve out the inside of each new wheel and replace the insides with quarter inch plastic discs that I machined on my sander and then drilled 4 holes through them to accept the metal adapter that came with the old wheels so that I could bolt them onto the wheelchair motors.
4. I brushed acetone on the plastic discs as well as the lawnmower wheel and then stuck them together. The acetone melts the plastic and then fuses the two together (acetone welding).

This is only one way to attach wheels to the motors. Be creative and I'm sure you will come up with another way to attach similar diameter wheels to the motors.

For this project I used 2 - 12v Lead Acid batteries. These are pretty heavy so if you can find some Lithium Ion ones, that would be a lot better. Originally I had these batteries in series for a total of 24 volts but found that the HoverDisk had the potential of travelling too fast and I could easily fall off. I then chose to use one battery for the motor power and one for all the accessories (lights, fan to cool the motor controller).

I also have another 5 volt battery pack to power the Arduinos and the sound effects board. I started with a pack of 4 AAs but since I posted the pictures, I switched this out with 4 Ds instead to give me a longer run time. This battery pack keeps the Arduinos and Xbee relay powered all the time.

This is the underside of the platform. I built it out of 3/4 inch plywood. The diameter is 30 inches. I made it this size so it can still fit through doorways at the school I teach at. The blocks you see are to hold various parts such as the motors and casters. I then spray painted it black to make it look nicer.

1. Cut out the shape you want from the plywood
2. Lay out the motors, batteries and castors so you can see how they will all fit
3. build supports to hold all of the above
4. paint the underside if you want

Here are some pictures of the wheels and castors attached. The wheels are off of an old wheelchair. The castors are 4 inches in diameter and made from nylon so they won't make much noise on a flat smooth surface. I put the castors on wooden blocks so they would end up at exactly the same height as the larger drive wheels. The last picture shows the batteries and electronics (more detail on this to follow). I built the housing for the motors out of the aluminium seat assembly from the discarded wheelchair but you could use any other substance that would hold it all together.

1. Bolt on the wheels and battery housing. I made sure the wheels were about half an inch up from the platform so that they could turn without rubbing on the platform.
2. Bolt on the castors in a way that they will not interfere with any of the other parts when they rotate. The castors must be at exactly the same height as the bottom of the wheels otherwise the unit will rock when you stand on it.

This is the top of the platform (the part you stand on). You have lots of options for this part. You could:

• Just paint the top
• Add a round piece of plastic that you could stand on (looks better than just plywood)
• Jazz it up with a ring of lights and logos like I did (see below for those steps)

1. Cut a quarter inch MDF ring approximately 3" wide as a perimeter (paint it to suit your needs)
2. Around the ring place 4 small LED lights (north, south, east, west) The one at north (which is the front), could blink. This would help you know which end is the front so when you stand on the platform you can orient yourself properly.
3. Inside this ring use a router and strait bit to cut a groove a quarter inch deep all around.
4. Inside this groove place a strip of high brightness LED lights that could turn on when the unit turns on. The lights all face inwards to light up the inner surface of the HoverDisk.
5. The inner circle is where you can place a logo (Captain America on mine). I printed the logo on a poster printer.
6. Cut a circle out of quarter inch Plexiglas to fit inside. The way I did this is I cut a circle out of wood first and made sure it fit exactly inside the LED strip and then taped the Plexiglas to the wooden circle and used my router with a straight pilot bit to follow the edge and cut out the Plexiglas. The Plexiglas is attached with four screws. This allows you to remove it and add a different logo if you want. In the end, the whole surface should be the same height (one flat surface).
7. Add a bumper guard to the outer edge. I use a 3/4 inch strip of silver automotive molding.

In order to make it appear that the HoverDisk is actually hovering, you need to cover up the wheels and castors. I did this by building a shroud around the whole unit that would hide everything. There are many ways to do this but I chose to use quarter inch MDF. I drew my plans out on paper and then designed brackets using 123D (3D printer software) and 3D printed them so that I could bolt all the separate parts together. The shroud stops about a half inch above the floor in case the HoverDisk has to go over a small bump or two.

I also ran a set of LED lights around the perimeter so that when you turn on the unit, it shoots lights downwards and helps to make it appear that the unit is hovering.

On one of the back panels, I placed a connector to charge the batteries as well as an on/off switch to shut off power to the Arduinos when the HoverDisk is not being used. There is also a small panel that you can unscrew which conceals the 5 volt power pack.

Here is a list of the electronic boards I used: (all documentation for these boards can be found in the diagram attached called : "Platform Wiring Diagram"

• 2 Arduinos - one controls the motors and one controls the lights, relays and fan.
• 2 Xbee units - prior to this I knew nothing about Xbees so I thought I would try to use them to provide the wireless capability. I did some research and was able to learn how to configure them to work.
  • These videos were really helpful to show me how to configure 2 Xbees to transmit analog and digital signals:

• 1 Adafruit AudioFX board - this unit can be programmed for various sound effects.
• 1 Grove Latching Relay - I used this to latch the lights on or off.
• 1 Power Relay and shield - This is a shield for Arduinos that provides a power relay. This activates the motors.
• 1 Sabertooth Motor Controller - Provides control for the motors.
• The Arduino sketches I created are attached

You have 2 options for the control of your HoverDisk:

Option A: Hard-wire the joystick to the Sabertooth Motor Controller.

This will eliminate the remote, Xbees, and one Arduino. The cost would drop considerably and it would be much easier to wire up. The drawback is you would either have a "handlebar" attached to the platform with the joystick and buttons attached to it, or a coil of wire that comes up from the platform into a hand-held remote with the joystick in that. If you want to go with this method the pdf document for the Sabertooth Motor Driver walks you through the hookup process. You would use the motor driver in Analog mode. The 2 center points of the joystick would connect to S1 and S2 of the motor driver.

Option B: Wireless remote using 2 Xbee units. (see diagram below)

If you go with this option you will be able to hold a remote in your hand and enjoy driving around without any wires to get in the way. The receiving Xbee will send the 2 PWM signals from the joystick and the 3 digital signals to the Arduino. The Arduino will then use the sketch I attached to convert the signals for the motor controller. I designed my remote using 123D and printed it on an Ultimaker 2 3D printer.

In case you have to transport your HoverDisk to a new location, it may be a good idea to build a travelling case for it. I built mine out of 5/8 inch plywood. It separates into two parts. This way you would put the bottom part on the floor, lift the HoverDisk into it and then cover it with the top part of the case. There are 3 clasps that secure both parts together and the HoverDisk fits snugly inside protected by foam rubber.

When you lift the case upright, there are 4 casters attached that allow you to roll the case around.

I know! it's a bit overboard but I needed to get the HoverDisk to my school safely :)

Oh yes! I made a stencil and sprayed a logo onto the case.

This is me on my HoverDisk driving around my basement (not the best location for this). The thumping sound you hear is the wheels going over the hardwood floor. I designed the unit to ride smoothly on flat flooring such as the floor I have at my school where I am a teacher. I hope you have enjoyed seeing my project and may think about building a similar unit. Don't be intimidated by any of the wiring or electronic boards that were used. Truly if I can do this, anyone can!

Happy Building!