Mini Solar Car With Micro:bit Remote Controller
Introduction: Mini Solar Car With Micro:bit Remote Controller
Before we start I must say that you may use right-click to open the links on a new tab. Otherwise, it is very annoying to wait for the page to load.
Hi everyone!
So excited to share my first Instructables project. I am an educator and I build this mini solar car as part of my job.
Some of my colleagues have been working on full-size solar cars with their students to participate in Solar Car Challenge. A full-size solar car takes a lot of effort and time as you may see in the video. We wanted to democratize this project so more students can benefit from it.
We had all the materials in our Innovation Lab which is a maker-space and we have many rapid prototyping tools like 3D printers, laser cutters, micro:bit, Arduino, and Raspberry Pi. So all I need to do is to put them together.
Supplies
The car chassis, wheels, and the DC motor are based on Junior Solar Sprint Competition Kit from Pitsco because we have been hosting the competition for a while and I already had the kit.
I used 2 micro:bit boards for remote control. You can buy 1 board and 1 Go bundle from Sparkfun. Since you only need the batteries and the battery holder for the remote controller.
We had the micro:bot kit from Sparkfun but I only used the moto:bit as the motor controller from the kit.
The solar panel (You may use the solar panel that comes with the JSS Kit or any other), the charger, and the rechargeable battery are from Adafruit. I used the Adafruit solar panel because it already comes with a DC jack connector. Otherwise, you need to solder one to JSS solar panel and this is discussed in the next steps.
You may see the material list here. There are options to choose from for each item.
Step 1: Build the Chassis With Some 3D Parts
You may use this pdf guide to build the car chassis but skip the panel support member section and do not install anything other than the wheels, gears, and motor.
The pdf guide tells you to glue the DC motor to the chassis but I used a 3D-Printed mount so I would remove it when needed. I attached the STL file so you can 3D print it.
There is something called spacers in the kit to mount the metal axle to the body and it also decreases the friction. 949
The ones that come with the kit are hollow cylinders but I designed a version with one flat side so it would be easier to glue to the chassis. The STL is also attached.
I tried designing some wheels for 3D printing as well. They are not very efficient since they do not provide enough traction on smooth surfaces.
Step 2: Attaching a DC Jack Connector to Solar Panel
The solar charger has a DC jack. If you are going to use Pitsco solar panel you might need to solder or screw a DC jack connector to it depending on what you have already. Both panels have similar specifications so you would save money if you just purchase the Ray Catcher kit.
If you are going to use Adafruit's solar panel you may skip this part since it already comes with the connector.
Step 3: Attaching 2-Pin JST to a DC Jack
The moto:bit has a DC power jack and the solar charger has a 2-pin JST Load output. Therefore, we need to solder or screw a DC jack connector to a 2-pin JST wire depending on what type of DC jack you want to use. You may need to check polarity: red to positive, black to ground.
Step 4: Soldering M/M Jumper Wires to Alligator Clips
*Update
Thanks to <PERSON> that you may use these jumper wires to skip this step.
*Original Post
In this step, we are going to connect moto:bit to the DC motor. We need to solder the alligator clip(comes with the JSS kit) to one end of the M/M jumper wires. You may see the pictures for details.
You can solder jumper wires to the motor directly but if you want to remove the motor and change the gear on it, it might be harder.
Step 5: The Codes
Before we assemble everything we should check if the setup is actually working. We will download 2 sample codes to micro:bits before the assembly since it might be harder to connect micro:bits to the computer when everything is in place. Especially the micro:bit on the chassis will be harder to reach.
The first 2 pictures are the codes for the remote controller and, let's say, "the driver". This will help us determine if the motor is running as expected before we assemble everything. 611