Introduction: Audi TTs 12V With Big Mac Button (Waylon)

About: Students at Wichita State University run a program that modifies off-the-shelf ride-on toy cars for kids with disabilities. Our cars feature more technical builds with joysticks and arduinos. We post our instr…

Here are some BEFORE pictures of Waylon's car.

Step 1: Gathering Parts/Materials


  • Yellow Audi TTs 12V (
  • 1 Relay
  • 1 Big Mac Button
  • Velcro Strips
  • Wood
  • Kill Switch Button


  • Measuring tape/ruler
  • Electrical tape
  • Duct tape
  • Screwdrivers
  • Drill
  • Drill bits
  • Wire
  • Wire Strippers/Cutters/Crimpers
  • Soldering Iron/Solder

Step 2: Assembling the Car

Tools Needed:

  • Phillips Screwdriver

Steps: These are covered in the instructions in the box as well.

  1. Remove car and parts from box and remove plastic wrapping.
  2. Using the screwdriver remove the cover over the battery.
  3. Connect the two four pinned connectors.
  4. Optional - Check if the car works by hitting the start button.
  5. Snap the seat into place.
  6. The 'A' frame that goes behind the seat snaps in as well, just line it up with the holes and push down
  7. Same with the side mirrors, they fit into the holes very easily.
  8. Line the holes up with the windshield and snap it into place as well.
  9. For the steering wheel, remove the plastic covering over the steering column. Slide the steering wheel over the column and use the provided long screw and nut that goes through the wheel and steering column, and fasten it down.
  10. To install the tires first find and separate the two tires marked rear and the two marked front.
  11. All four tires need to have the wing nut attached.
  12. Put the car onto its left side and install the right tires marked front and back, by sliding them over the rod until they click.
  13. Repeat step 12 for the left two tires.

Step 3: Installing the "Emergency Stop Switch"

We needed to install an emergency stop switch for Waylon's parents to be able to shut the car off completely. This switch would disable all of the electronics and the motor, but would still allow charging. To do this we had to track down the main power wire that ran from the battery to the circuitry that controlled the motor and the dashboard, and then connect this switch making sure it was not in the charging circuit so it could be charged when off.

Step 4: Step 4: Installing the Big Yellow Go Button

The switch that makes the car go is in the form of a pedal, where a normal gas pedal would go. However, Waylon is not able to use the pedal that comes default with the car. To fix this we installed a big yellow button on the steering wheel that takes the place of the pedal. To do this we originally thought we would need the button and a relay to ensure the safety of Waylon and his new car. Upon disassembling the car to find the wires leading from the pedal to the battery we found that our car had relays built into the circuitry. So all we had to do was connect the button to the wires that controlled the pedal via wire nuts.

Step 5: Step 5: Modifying the Seat to Accompany Waylon's Size

To accompany Waylon's size we moved the seat forward by adding three two by four boards that we wrapped in vinyl behind the seat, and two support two by four boards underneath the seat. To do this we wrapped each board separately and screwed the first board to the car, and then used velcro to attach each board to each other. This enables the car to grow with Waylon, as each board except the final one can be removed with ease. The boards underneath the seat are also wrapped in vinyl and screwed to the floor of the car but attached to the bottom of the seat with velcro. After all of that was finished we added a chest strap for Waylon's safety at the recommendation of his physical therapist.

Step 6: Step 6: Creating a Custom License Plate for Waylon

We used the laser wood cutter in the shop at the direction of Nathan Smith to engrave a custom license plate with Waylon's name on it out of MDF.

Step 7: Step 7: Delivery!

Now that our car is completed it is ready to be delivered to Waylon and his parents!