How to Make a Solar Car!

This is the simple guide to create a basic solar car! You can choose to substitute or avoid using certain materials to create a more durable or customised car.

Supplies

To create a simple solar car, you will need:

• 5+ zipties
• 1 small solar panel
• 1 microbit
• 1 servo (optional)
• 2 metal axels (you can choose to use wooden skewers)
• 4+ crocodile clips
• 1 capacitor
• 2 bearings (use more if required)
• 2 small recycled/3D printed wheels
• 2 larger recycled/3D printed wheels
• 1 breadboard
• 1 roll of double sided tape
• 1 hot glue gun
• 2 hot glue gun sticks
• 1 motor
• 3 'powerrails'
• 1 medium sized piece of acrylic (30cmx30cm)

Note: you will require and laser cutter and/or a 3D printer to complete this project, but it is possible to use recycled materials or other substitutes.

Step 1: Laser Cutting a Chassis

Start your project by creating a 'chassis' or a base for your car on a software such as Onshape. Create a square shape with an added semi circle on one side. Make sure that your design is around 15cm x 25cm in length and width or an equivalent ratio.

Next create cut outs within your shape, one following the outline on the semicircle and several long and several thin rectangular strips along the chassis. This will make the solar car significantly lighter and easier to attach components later on. Your design should look similar to the image above.

Next, download your creation and upload them to the software of your choice to begin laser printing! You may choose to use acrylic, wood or any other type of durable material to create the base of your solar car. Make sure you double check the positioning of you material and that the strength of the laser is appropriate.

If you are unfamiliar with using a laser cutter, use any of the attached links and videos for resources!

How to upload files to a laser cutter

How to use a laser cutter

Step 2: 3D Printing Components (optional)

In a software such as Tinkercad or Onshape, create two large back wheels. Optionally, you may chose to include divets, holes and other features to maximise the grip and weight that you wheels will have. You can experiment with different materials around the 'tire' outline, such as elastic bands, rubber, recycled tire and much more! If you have troubles creating a wheel, you can either watch a tutorial on how to create one, or browse the hundreds of freely available models to down load:

Pre made wheel designs

How to make a wheel on Onshape

Your wheels should be around 5cm tall and between 1cm and 2.5cm wide.

Step 3: Coding the Microbit

Plug your microbit into you computer using an adapter or another, then open a new project to begin your code. You will first need to download the DF-Driver extension pack which can be found when pressing extensions, then searching the name. Press download and then it can be found along the side bar of your microbit. Then you can start!

• Using the pink 'on button A press' , drag 'motor dir speed' into the input. Select 'M1', 'CW' and the speed to 225 on this block.
• Under basic, select pause and change the number to 5000
• Select DF-Driver and drag the 'servo' under the 'pause' feature. Change the variables to 'S1' and '90' degrees
• Once again, select pause and change the number to 5000
• Next select 'servo..degree..' and select 'M1' and degree '0'
• Finally locate motor stop and alter the setting to 'M1'

And you done! You microbit block code should look similar to the image attached.

You can create your own code using another software or create a different methord on microbit.

Guide for a basic microbit code

Step 4: Assembly 1

The next step is to assemble your car! To do this, use your creativity to find substitutes to bind your car including:

• Hotglue
• Bluetack
• Masking tape
• Double sided tape
• etc!

Using a hotglue gun carefully, layer a thin layer of glue to the middle base of the chassis and gentle aline the two parts. Then, use a mixture of zipties and double sided tape to secure the micro bit, DF-Driver, capacitor, MPPT and breadboard to the chassis of the car.

Tip: Attach the chassis and the motor together with the wheels attached to ensure that the wheels are not scrapping the car. Carefully and thoughtfully design where you are placing the solar cars components (e.g capacitor near the solar panel)

*be careful using hotglue*

Step 5: Next Up: Wiring!

Follow the instructions to correctly wire your solar car with crocodile clips:

• Screw the positive and negative wires from the solar panel into the inputs of the MPPT's longer side
• On the shorter side of the MPPT, connect the positive wire to a capacitor
• From the capacitor, use the negative and positive wires to connect them to the expansion board, tightly screwing the wires shut
• On the opposite of the micro bit, connect the servo
• Follow the image to connect the bread board to the remainder of the wiring

Prevent a short circuit by using non conductive materials such as wood, plastic and other insulators! You can check if your solar car is short circuiting with the video above.

Step 6: Servo, Axel and Front Wheels

To create a stable support for the servo, use hotglue to stick one edge of the servo to the front of the chassis. On the other bracket, use hotglue again to glue a metal axel or wooden skewer in the middle. Then, glue the parts of the axel to where it meets the chassis on either side. This will allow the servo to be connected to the front wheels, aswell as being very stable. You can see our example in the image above.

Using zipties, attach the servo to a 3D printed tube or recycled cylinder. Separately, thread several bearings on either sides of a metal axel, then follow the bearings with the servo tube and block the creation with a small wheel on both sides.

Step 7: Finishing Touches!

Use any scraps of 3D printed acrylic or other recycled materials to prop the solar panel above the car. Use hotglue or superglue to secure it to the chassis. It should look similar to the image above.

Before attaching your solar panel to, use any extra zipties, tape or blue tack to tidy up the wiring and any rough edges on your solar car.

Finally, use double sided tape to temporarily attach the solar panel to the car! With double sided tape, it is easier to alter the interior if needed.