Baby Bug Learning Toy

A project made possible with collaboration with Shriners Children’s, Salt Lake City and Open Wheelchair Foundation

The Baby Bug is a powered mobility device for children 8 months until 18 months of age or when outgrown. It is designed for children with mobility impairments. It is a tool that allows the child to experience self-initiated mobility with the goals of allowing them to experience the cognitive, social and the developmental benefits mobility provides to a developing child. This should be used under the direction of a licensed Physical Therapist or a licensed Occupational Therapist.

 “We learn to move and we move to learn throughout each day.” (Sabet et al, 2022)

Baby Bug in Action

PDF with list of materials included: 'Baby Bug parts'.

Once the seat is assembled remove the rubber feet on the bottom. Be sure to save the screws as they will be used later in step 8 to install the battery box. A sharp chisel can be used to cut off the raised plastic lip around where the rubber foot was. This will allow the base plate to be flush with the seat.

Using a CNC router cut the base plate from the 0.25" thick plastic sheet. If a CNC router is not available print out the template and use it as a guide to cut the base plate by hand. Pound in the pronged tee nuts on the top and bottom as shown in the picture.

Bolt the casters to the baseplate with the 3D printed spacer in between using the 0.75" long bolts. The motors can be installed in their 3D printed housing using the 10 mm bolt and then bolted to the base plate using the 0/75" bolts.

Using the 1.5" long screws line up the baseplate with the seat. The 1.5" long screws will be going into the holes left by the rubber feet in Step 1. Be careful not to over tighten the screws as it could cause the screw to pull through the plastic.

Use a small drill bit to drill a hole through the remaining four pronged tee nuts and out the top of the seat.

Note: It is critical to use a small drill bit that will not damage the threads of the tee nut.

It can be very difficult to drill a straight hole so use two people to help line up the drill from multiple angles. You will need to enlarge the hole ONLY in the Sit Me Up seat system from the top down to allow the 2” bolt to fit through the seat base. Push the 2" long bolts through the top of the seat and secure them the into the pronged tee nuts.

The two bolts on the front of the chair will extend past the bottom of the base and will need to be cut off with either a Dremel or hacksaw.

For best results, mark the screw when in place at the desired length. Remove screw and place in vice. Cut screw at desired length. Smooth surface with a file to prevent a scratch point and to provide a nice finished surface.

Note: From this point on, we reference the pictures much more. We recommend pulling up the Instructibles in two tabs (or better yet two screens) so you can more easily switch between the pictures and the words.

Insert the 3D printed joystick adapter into the joystick and drill a pilot hole through the joystick and into the joystick adapter (Pictures 1 & 2). The dill bit used should be thinner that the screw used to secure the parts.

Insert the cable through the joystick adapter and into the joystick (Picture 3).

Clip and file smooth one of the 1.5" screws short enough so it does not not damage the cable when screwed into the 3D printed parts (Pictures 4 & 5). Drive in the screw securing the joystick to the joystick adapter.

Place the joystick assembly under the front of the seat by aligning the notch with the center tab on the underside of the Sit Me Up tray (Pictures 1 & 2). This will assist you in centering the joystick. Drill pilot holes using a 7/64" drill bit through the top of the seat and into the joystick adapter (Picture 4). A flashlight can be used to help locate the position of the joystick adapter (Picture 3). Use two 1.5" screws to secure joystick to Sit Me Up tray.

Secure the cable to one of the ribs near the left side (standing behind the device) of the tray by drilling a hole and looping a zip tie through the hole (Picture 5).

Using a 13/16" bit (or step down drill bit ) drill two holes the the battery box. Hole 1 is for the charging adapter (Picture 1) and hole 2 is for the wires from the electronics (Picture 2). Drill hole 1 for the charger in the top left corner of the box when viewing the box from behind. Having the hole higher up will make it easier to plug in the charger after the battery box is attached to the base plate (Picture 3). Hole 2 for the wires and cable should be in the bottom left corner of the battery box when viewing the box from behind. Having the hole lower in the box to allow the electronics within the battery box to better fit (Picture 2).

Place the battery box behind the seat and flush with the seat frame (Picture 3). Drill four pilot holes using a 7/64” drill bit through the battery box and through the base plate. Using the screws from the rubber feet in Step 1, secure the battery box to the base plate (This can be seen best in Picture 2).

Use the provided screws with the charging plug to screw it into the battery box. It is important to clip off the extra screw length to make the box safer to work on (Picture 4).

Install the black cable connector in the back of the battery box and thread the joystick cable through the cable connector and into the battery box. The green plug on the end of the joystick cable needs to be temporarily removed to allow the joystick cable to fit through the cable connector. Note that the cable has two white wires, one with a blue stripe and one with a brown stripe. It is important to make sure the wires are properly reinstalled (Pictures 6 & 7).

Take the power cables from the box with the charger and clip off the eyelets (Picture 1). Strip and twist together the exposed wire to the red and black wires included with the joystick (Picture 2). The wires need to be twisted together in parallel (Picture 2) as the ends will be installed into the blue processor box. Install the blue processor box using the adhesive velcro (Picture 6 for position and orientation). Install the wires into the blue processor box (Picture 5) and the other end to the charging adapter installed in step 8 (Picture 6).

Note: Soldiering the twisted ends together will make installing them into the bule processor box easier and create a more durable/reliable connection. Either way, be sure the set screw is tight so they don't pop out of the blue processor box when tugged on (Picture 5). For those unfamiliar with soldiering (Its easy!), go to youtube and search: 'How to solder two wires together | Crutchfield'

Install the green and purple wires onto the two motors and push the wire ends through the hole in the center of the base plate (Picture 3). The wires can then be threaded into the battery box (Picture 4). The purple wire is being used as the positive lead and is attached to the motor terminal with the red dot (Picture 3). A piece of colored tape is placed on the left motor and on the end of the wires coming from the left motor to help differentiate the left motor wires from the right motor wires (Picture 5, tape is yellow). Install the wires into the blue processor box (Picture 5).

Install the battery using the adhesive velcro. Install the leads onto the battery and tuck the wires in the box (Picture 6). There should be a twisty tie that came from the charging kit that you can use to contain the wires

When the blue processor box is installed you will notice a small black dial on the right side (Picture 7). This dial is the manual override for the device speed. You can limit how fast the device can drive by adjusting this dial.

Install the battery case lid.

Tip the Baby Bug over and install the 3D printed cover over the motors/wires using two 0.75" bolts (Picture 8).

This video better shows the drive wheel assembly.

https://www.youtube.com/watch?v=k0DEdS7-k1A

Note: The inner and outer wheel clamps are under a lot of stress and should be printed at 100% infill.

Remove the bearings from the center of the drive wheels. A punch or metal rod can be used to make this process easier.

Push the hex nuts into the inner wheel clamp. One of the 2" bolts can be used to help position and push the nuts.

Press both the inner and outer wheel clamps onto the wheel and bolt them together using the 3/4" long bolts. If the bolt do not go in smoothly use a small drill bit to clean out the holes. Loctite should be used on the bolts to prevent the wheels form coming off.

The last step is to install the cloth seat cover.

While the child is still learning the cause and effect of the joystick a training joystick can be attached to the front.

When the child reaches out and touches the training joystick the parent can control the real joystick teaching the child that they can move if they touch the joystick.

The training joystick is assembled using two 3D prints, one of the 1.5" long bolts, and associated nut.

Optionally a colorful joystick toper can be printed and installed.

Note: When swapping the joystick topper be very careful not to twist the base of the joystick. If the base of the joystick is twisted it will break. Pilers can be used for extra grip.

The device does not move: The device as a time out feature where the device will automatically turn off after a prolonged time of inactivity. Turn the device off and then on again.

The device is too fast or too slow: The speed of the device can be set using a small black dial on the right of the blue processor box inside the electronics box. (See Picture 7 on Step 9)

The device is not charging:

The drive wheel came off: Inspect the 3D printed plastics around the drive wheel for damages or wear. If there is no damage or wear the wheel can be reattached using an Allen wrench. Be sure to use Locktite and not to over tighten the bolt. If the 3D printed part is damaged or has wear the part will need to be reprinted.

One of the drive wheels wont turn or wont stop turning: The blue processor box has malfunctioned and will need to be replaced. Contact the seller of the Baby Bug or the seller of the blue processor box for a replacement.

The joystick is broken: If the joystick can be twisted it is broken. Open the bottom of the joystick and wrap the broken part in thread and then soak the thread in super glue. Alternatively the joystick can simply be replaced. If the joystick does not twist do not force it, twisting the joystick will cause it to break.