DIY SOLAR POWERED CHASSIS (USING a CAPACITOR)

3D printed, laser cut using MDF board, DIY solar powered chassis (using a capacitor)

(near) final product.

Supplies

Download the attached PDF for the listed supplies you will need for this project.

Step 1: Printing Out Chassis Components

Print out attached chassis components with laser cutter on MDF board.

• 1x Chassis Body

Print out attached chassis components using a 3D printer

• 4x Wheels
• 1x Motor Holder
• 1x Micro Servo Holder

Alternatives: If you don't have access to a laser cutter, feel free to copy the measurements attached and sketch out the design on cardboard to then cut out.

If you don't have access to a 3D printer to create wheels or a motor holder, you can find and purchase similar designs online that serve the same purpose.

Step 2: Front Wheels & Steering

1. To create the front steering system, start with cutting a strip of plastic cardboard that will be wide and long enough to fit your axle rod (10 to 15cm). 
2. Slide the axle rod through the plastic cardboard strip and attach one of yout 3D printed wheels to each side. Secure with glue or another adhesive if necessary.
3. After this, you will need to slide the micro servo into its mount/case (3D printed in step 1) and then attach its hardware blade (plastic attachment in + shape that is provided with your purchase). 
4. Next, use double sided tape and cable/zip ties to secure the servo component to the plastic cardboard component. This is now your front steering system. 
5. Then, attach this newly made system to the chassis (cut in step 2) using screws in the servo mount or other adhesives. See image for reference (look at steering setup at the front of chassis, don't be frightened by the rest of the vehicle!)

Step 3: Chassis' Wiring

Connect the following using either dupont pins and or alligator clips

1. Connect capacitor to the solar power manager, using alligator clips to connect the driver expansion to the solar power manager. Wire the battery to the driver expansion board
2. Connect capacitor to solar panel manager
3. Connect expansion board to capacitor (powers expansion board)
4. Make a resistor circuit on breadboard to help divide voltage. 4.2v divided into 3.3v and 0.9v.
5. Connect GRND point from expansion board (micro:bit) to first point on resistor circuit
6. Then connect 0pin point from expansion board (micro:bit) to second point on resistor circuit -The micro:bit not only measures voltage across the resistor circuit, but also controls the motors for the capacitor to improve efficiency

Step 4: Assembly

Now that we have our main components together, it's time for assembly.

1. Put your motor into the 3D printer motor case. Then attach wheels, (screw or glue to secure), and attach to chassis with cable/zip ties.
2. Upload the following code to your micro:bit, (click link for assistance) then place your micro:bit into the expansion board (facing outwards to the edge of the chassis)
3. Make sure at this point that all the components of the chassis are secure, and that the wires are kept in place to avoid damage.
4. Then finally, place your solar panel on top like a roof. You can attach this with cable ties to the chassis, or you could prop it up with pieces of acrylic or spare lightweight board material.