Jeep Modification - Acceleration With a Button

DISCLAIMER: The Barstow School and FRC Team 1939 or any of its members are not responsible for any injuries to any person or damages to any object including the car caused by the modifications. Any type of modification will also void the warranty provided by the manufacturer of the car.

Established in 2006, The Barstow KUHNIGITS is a FIRST Robotics Competition team located at The Barstow School in Kansas City, Missouri. See more about us at: www.frcteam1939.com

Our award-winning head coach, Gavin Wood, teaches his students how their STEM skills can help make the world a better place and inspire the youth of today to pursue careers in STEM fields and creates the leaders of tomorrow.

In 2015, we began our partnership with Variety KC GoBabyGo Powered by Rockhurst University led by Kendra Gagnon in Kansas City, Mo. GoBabyGo is an international organization founded by Dr. Cole Galloway to provide children with disabilities the opportunity to move independently. Variety KC has generously provided donations to buy all the necessary parts and cars for modification.

The Ride-On Truck from Best Choice Products (LINK) was built and modified as a result of the collaboration between our team and GoBabyGo. Aasim Hawa, Aiden Jacobs, and George Whitehill from The Barstow School led the modification of the car. Gavin Wood, Andrea Wood, Mason Phillips, Lexi Dixon, Sean Mathews, and several other team members also helped with the adaptations. Aasim Hawa and Aiden Jacobs compiled these instructions. Dr. Kendra Gagnon also contributed to this manual.

Modifications include:

  • A PVC exoskeleton backed with pool noodles for cushioning.
  • A kickboard to the back of the seat to increase back support for the child OR a harness for the child.
  • Converting the acceleration mechanism from a pedal to a button placed on the steering wheel.
  • Adding a kill switch to the back of the vehicle.

Step 1: Gathering Parts and Supplies

Below are the lists of all the parts required for the modification. Most of these will be found in hardware stores such as Home Depot or Lowe’s, unless otherwise noted. The electronics have hyperlinks directed to the product pages for order. The internal modifications require skills in soldering and wiring.

PVC Exoskeleton:

  • PVC Pipe - ¾”
  • CPVC Pipe - ¾”
  • Zip ties
  • PVC elbows (3/4") - 4 pieces
  • PVC T-connector (3/4") - 2 pieces
  • CPVC (3/4") to PVC (3/4") connectors - 4 pieces
  • PVC 3-way elbow connector (3/4’’) - 2 pieces
  • 1 ½ inch wood screws - 1 box
  • Pool Noodle - 2 ¼’’

Electronics:

  • Switch:
    • Used to turn the car on and off
    • LINK
  • Large Push Button
    • Used to accelerate the car
    • LINK
  • Wire - 16 gauge
  • Ring Terminals for wiring
  • Spade Connectors for wiring
  • Butt Splices
  • Zip Ties
  • Electrical Tape
  • Velcro

Tools:

  • Measuring Tape/Ruler
  • PVC Cutters (Hack saw will work as a substitute)
  • PVC Glue
  • Drill
  • Drill Bits - 15/32”, pilot hole bit
  • Screwdrivers
  • Pen, pencil, or marker
  • File
  • Pliers
  • Hot Glue Gun and Sticks
  • Wire Strippers
  • Soldering Iron
  • Solder
  • Wire Cutters
  • Crimpers
  • Heat Gun

Step 2: Assembling the Vehicle

IMPORTANT NOTE: Do not assemble the vehicle according to the instruction manual given with the car; instead, use these instructions. The instruction manual given with the car includes steps that inhibit this modification and cannot be undone.

  1. Flip the vehicle over, and remove the rear axle located underneath the vehicle on the left side of the vehicle's shell. For reference, consult image 1.
  2. Attach the rear axle. First, remove the nut and bolt from the rear stabilizer bars. Then, insert the rear axle through the gearbox’s stabilizer bars and suspension modules. Align the holes in the axle with the holes in the rear stabilizer bars, and reinsert the nut and bolt to secure the rear axle. If these steps are completed correctly, the rear axle should be locked into place. For reference, consult image 2.
  3. Insert the wheel’s rear wheels onto the rear axle so that the gear side of the wheels faces toward the inside of the vehicle. Place the large washers included with the vehicle on the rear axle. Secure the wheel by inserting the pin into the hole in the axle and bending the pin using needle nose pliers. Attach decorative hubcap to wheels by aligning the tabs with the slits in the wheel. For reference, consult image 3.
  4. First, slide the front axle into the steering column so that the bar sinks into the car and the plates for the bolts align with the holes on the vehicle. Secure the axle using the screws provided. Place the large washer onto the shaft that extends to the front of the vehicle from the steering column. Secure this shaft by inserting the pin and bending the pin using needle nose pliers. For reference, consult image 4.
  5. Place the front wheels onto the front axle, ensuring that the side of the wheel that the hubcap would fit on faces outward. Place the large washers onto the axle. Secure the wheel by inserting the pin and bending the pin using needle nose pliers. Attach the decorative hubcap to the wheels. For reference, consult image 5

Step 3: Assembling the PVC Structure

IMPORTANT NOTE: There are two options to modify the seat: a kickboard or a harness. Please read through both options, and then decide which option suits the child the best. Also, keep in mind that many parts are difficult to remove once they have been secured.

  1. Cut out the PVC (or CPVC) according to the sizes listed below using a PVC cutter. Be as precise as possible.
    1. 4 pieces of 5 ¾ inch PVC
    2. 4 pieces of 7 inch PVC
    3. 2 pieces of 4 inch PVC
    4. 2 pieces of 3 ¾ inch PVC
    5. 4 pieces of 2 ½ inch CPVC
  2. Then, assemble the PVC structure as shown in image 1, using the connectors as appropriate.
  3. To attach the PVC structure to the vehicle, insert the PVC structure into the 4 holes in each of the corners surrounding the seat. Use the 4x 1.5 in. wood screws to attach the PVC frame to the car by drilling through the plastic shell and into the PVC. Using a pilot hole is recommended. For reference, consult image 2.
  4. Use the wood screws to secure the PVC structure together. Drill a wood screw at every attachment between a piece of PVC/CPVC and connector.
  5. Attach 4 pool noodles to the PVC sections that act as seat handles, as shown in image 3.
  6. Based on what suits the child best, select one of the following two options:

Option 1: Boogie Board

Drill 4 holes in a rectangle into the boogie board, and use zip ties through these holes to secure the boogie board against the PVC exoskeleton. Consult image 4.

Option 2: Harness

Place a pool noodle on both the top and bottom PVC crossbar at the back of the truck. Zip tie these pool noodles into place. Secure the harness by wrapping the harness bands around the pool noodles or using velcro. Consult image 5.

Step 4: Wiring the Kill Switch

  1. Open the vehicle’s hood to uncover all of the electronics.
  2. Cut the wire between the positive battery terminal and the breaker. Cut about one inch from the spade connector that attaches to the battery lead. Strip about ¼’’ of insulation off of each side of the wire that was just cut.
  3. Prepare a 50-inch wire harness that has ring lugs on one end and is stripped bare on the other end. Cut a 50-inch long wire. On one side of the wire, strip off about ¼’’ of insulation, and crimp on a ring terminal (ring lug). On the other side of the wire, strip off about ¼’’ of insulation, and leave it bare. For reference, consult image 1.
  4. Splice the wire that was cut in step 2 with the wire harness prepared in step 3. Place one end of the stripped side of the wire harness into one side of a butt splice, and place one end of the wire cut near the battery into the other side of the butt splice. Using a crimper, crimp the butt splice. Use a heat gun to heat shrink the butt splice. Repeat these steps with the other two ends of the wires. Alternatively, use wire nuts instead of butt splices to splice the wires, or solder the wires together. NOTE: The color of the wire does not matter, because it is going to a kill switch, in which the orientation of the positive/negative wires does not matter. For reference, consult image 2
  5. Guide the wire harness through the hole that is near the battery, as shown in image 3.
  6. Direct the wire harness underneath the left wheel housing and make sure to tape the wires so that they do not get caught in the wheels of the car, as shown in image 4.
  7. Mount the kill switch. Drill a 15/32” hole into the bottom left corner of the backside of the truck. Fit the kill switch through the drilled hole so that the threaded portion of the switch fully fits through. Screw the nut onto the switch. After the switch is mounted, secure the ring lugs onto the kill switch by screwing them onto the back ends. If the switch has ON and OFF labels, make sure to align the OFF position to be downwards. For reference, consult image 5.

Step 5: Wiring the Button

  1. First, locate the wires that will be cut for this modification. Find the white plug located underneath the dashboard, and unplug it. Note the orientation of the plug (blue wire on top, orange wire on bottom). Also, find the bundle of wires that originates from the pedal and cut both of the ground (brown) wires that run to/from the pedal. For reference, consult image 1. Strip off about ¼’’ of insulation from the ground wire that runs from the white plug, and strip off about ¼’’ of insulation from the ground wire that is in a bundle with a blue and red wire. For reference, consult image 2. Discard the bundle of wires running to/from the pedal; those will no longer be needed for this modification.
  2. Prepare a 32-inch wire harness that has spade connectors on one end and is stripped bare on the other end. Cut a 32-inch long wire. On one side of the wire, strip off about ¼’’ of insulation, and crimp on a spade connector. On the other side of the wire, strip off about ¼’’ of insulation, and leave it bare. For reference, consult image 3.
  3. Splice the two ground wires that were cut in step 1 with the wire harness prepared in step 2. Place one end of the stripped side of the wire harness into one side of a butt splice, and place one end of the ground wire cut into the other side of the butt splice. Using a crimper, crimp the butt splice. Use a heat gun to heat shrink the butt splice. Repeat these steps with the other two ends of the wires. Alternatively, use wire nuts instead of butt splices to splice the wires, or solder the wires together.
  4. To mount the button onto the steering wheel, guide the wire harness through one of the two large holes above the dashboard where the windshield would have been placed.
  5. Assemble the button and mount it onto the steering wheel. We used a laser-cut mount.
  6. Attach the spade connectors to the button. One wire should be attached to the terminal on the bottom of the limit switch, and one wire should be attached to the terminal on the side of the limit switch. You may have to exchange the wires between these two terminals for the button to work. Zip tie the wires around the steering wheel column. For reference, consult image 4.

Step 6: Operating the Jeep

To sync the remote control with the car:

  1. Turn off the vehicle.
  2. Press and hold the button at the top of the remote control until the light on the remote flashes.
  3. Turn on the vehicle.


To use the remote control:

  1. To change the speed, press the S button. The lights indicate the current speed level of the car.
  2. To use the emergency brake/park feature, press the P button. To deactivate the brake/park, press the P button again.
  3. NOTE: The directional controls on the remote control override the directional controls on the vehicle.


To charge the vehicle:

  1. The charging port is located under the power button and radio on the dashboard.
  2. A typical charge takes 8-12 hours, and do not charge for more than 20 hours.
  3. Make sure to turn off the car while charging.

Step 7: Troubleshooting

If your child is too large, try one of the following:

  1. Place cushions on the seat to elevate them and allow more vertical leg room.
  2. Remove the plastic seat and put a cushion on the bottom for more lateral space
  3. Modify the PVC exoskeleton to allow your child to fit into their seat better.
  4. There is no one "right" way to improve your child's fit in the car - be creative!


If the Jeep won’t move:

  1. Ensure the kill switch and power button are set to the ON position, the shifter is not in the neutral position, and the emergency brake on the remote control is off.
  2. Make sure that the wires are plugged into the button, and check under the hood for any loose wires.
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