The Go Baby Go project seeks to match young children with developmental disabilities with custom cars to aid in freedom of movement. We modded a car for a young boy named William. William had been diagnosed with William's Syndrome, a condition that results in mild intellectual disability, distinctive facial features, cardiovascular issues, and delayed development.
Step 1: Background
- Implement a speed controller (potentiometer) to change maximum velocity of car, which ultimately reduces the acceleration of the car. Although William is able to hold his head up without problems, we still wanted William to be able to sit comfortably in the car without being startled by the car accelerating.
- Sought to construct a car that acts as a method for William to get around easier rather than a speedy toy car.
- Reduce the distance from the seat to the steering wheel, and make the seat adjustable so William is able to sit comfortably and extend the car according to his growth.
- Modify the way the car accelerates, by removing the foot pedal and adding a button to the steering wheel to be pressed by William applying pressure to the PVC pipe when steering.
- Ankle braces and short legs make it hard for William to control the car with his foot.
- Also wanted to simplify the functionality of the car so he only has to focus on using his hands to operate the car.
Step 2: Supplies Needed
- Disney Pixar Cars 3 Lightning McQueen https://www.toysrus.com/product?productId=1205912...
- 12” PVC pipe Buckle and buckle strap
- DROK DC Motor Control 6-30V Motor Speed Controller Board
- Black pool noodle
- Batman fabric
- 1’ x’ 1’ foam square
- 3-prong button
- Velcro tape
- Spools of insulated wire
- Plastic 10 ml pipette
- Two 4” screws
- Yellow duct tape
- Foam circle for button
- Solder iron
- Wire Cutter and stripper
- Wire crimper and crimp connector set
- Hot glue gun
- 3-D printer
- Heat gun
- Foam cutter
Step 3: Inserting Speed Controller
To insert the speed controller, we first had to remove the lid covering the motor and charging port, the steering wheel compartment, and the wire cover underneath car in order to determine original circuitry of the car. We diagrammed the car's original circuit by following the wires connected from the power supply to the motor and using the multimeter to determine the according terminals on the switches within the circuit. We then had to determine where we were going to add the new speed controller, after removing the previous forward/reverse switch.
Step 4: Make Sure the VSC Works!
After connecting the speed controller we tested the car's updated circuitry by switching between forward and reverse while pressing the pedal.
Step 5: Drill Hole for Potentiometer Knob and Notch
After successfully integrating the VSC into the circuit, a hole was formed into the side of the car for the potentiometer to be placed in. We then tested the potentiometer's ability to alter the maximum velocity of the car and it worked very well.
Step 6: Secure Speed Controller on Base of Front Hood
The VSC was then attached to the inside of the car's front dashboard, so it was in close proximity to the potentiometer, power switch, and forward/reverse switch.
Step 7: 3-D Print New Forward/reverse Button Hole and Attach It
Since the new forward/reverse button being used was too small for the original slot left by the removed forward/reverse button, a plastic piece fitting the holes dimensions needed to be created to secure the new button in place.
The piece was designed using Tinkercad and 3-D printed according to the following dimensions:
Inner dimensions: .861” by 1.115”
Outer dimensions: 1.3855” by 1.135”
Step 8: Insert New Switch From VSC
After the plastic piece had been printed, it fit perfectly into the slot and allowed for the button to also be placed in snuggly.
Step 9: Seat Adjustment (Optional)
Since William's measurements showed he wouldn't be able to reach the steering wheel comfortably, the seat needed to be adjusted to a position closer to the steering column. The seat was initially unscrewed from its original position and locations for the new placement of the screws was determined using William's measurements. Four rows of holes were drilled into the plastic beneath the seat at a comfortable distance from the steering wheel and the holes were then threaded to fit the M3 screw size. Washers and M3 screws were finally used to screw the seat in at a forward position.
If the supplies to change set screw positions is not available, a foam backboard can be implemented as an alternative way to scoot the child closer to the steering wheel. The prototype photo uses screws, but this backboard should be attached with velcro or some more comfortable connector.
Step 10: Rerouting Pedal Control to Steering Wheel
Since William wouldn't be able to reach and operate the pedal with his feet, an acceleration button needed to be placed on the steering wheel. The wires were detached from the pedal, and the multimeter was used to determine the white wire as the common ground. The common ground was found to be the bottom terminal of the blue 3-pronged button, and the white wire was connected to the ground. The blue wire was attached to the prong closest to the top of the button, and the yellow wire was then connected to the middle prong. The wire configuration was successful, as the button was able to accelerate the car.
Step 11: Extend Wires From Pedal Port Through Steering Wheel
The interior of the steering wheel, which included a speaker, was removed and drilled through to create room for the blue button. However, there wasn't enough depth in the steering wheel, so a circular foam disc was needed to raise the button out of the steering wheel. The wires to the button were extending using small intermediary wires able to fit through the wholes underneath the steering wheel. These wires were crimped to the previous wires and soldered to the button to complete the circuit modification of the car. The wires were placed out of sight within the car, and all the compartments of the car that had been removed were screwed back into place.
Step 12: Seat Belt, Booster Seat, and Side Supports Additions
For William to sit securely within the car, side supports, a seatbelt, and booster seat were added to the car. To create the booster seat, a block of foam was cut in the shape of the seat bottom. The foam was then wrapped in Batman fabric and Velcro was glued to the seat and booster seat to fasten it in place. Two 16" pool noodle pieces were also cut and flattened on one side to be used as side supports. These pieces were covered in Batman fabric, and Velcro was again glued to the car and the pieces.
Step 13: Cross Bar Construction
To add the steering crossbar, holes big enough to fit the pipettes were first drilled into the cavities of steering wheel. Holes corresponding to the same distance as those in the steering wheel were then drilled into a 12" piece of PVC pipe, and threaded for ¼” diameter screws. Next, the ¼” screws were screwed into the PVC pipe and the square heads of the screws were hammered into the top holes on the PVC in order to flush the heads against the PVC pipe. The PVC pipe was then wrapped in yellow duct tape to allow William to distinguish the crossbar from the rest of the car, and improve the cause and effect realization of applying pressure to the pipe and the car accelerating.
Step 14: Accelerator PVC Bar and Pipette Installation
3" pipette segments were inserted into the holes of the steering wheel, and the pipette sleeves were held in positions with the least friction with the screws. The PVC pipe was placed on the steering wheel with the screws inserted through the pipette segments, after the pipette sleeves were glued in place. Finally, the nuts were screwed onto the bottom of the screws and rubber bands were placed underneath the steering wheel to prevent the PVC pipe from getting stuck in the accelerating position.