The first thing to do in any DIY project is to choose the project and decide which part to buy or reuse. This is not an easy choice because there are so many options and you often have to revise some of your choices during the project and of course you want to stick in an acceptable budget. In my case I kept the cost under 50 € by purchasing some pieces on eBay shipped from China.
For a complete list of parts used in the different projects please refer to the part list page.
The Controller card:
There multiple controller card or even credit card size computers that can be used. I decided to go with an arduino because:
- it offers a good value for a low price
- it comes in multiple sizes that can be easy to integrate
- there are a lot of tutorial on the web to help you
- you can find modules and the corresponding code very easily.
First getting ideas
I look to projects like this one: Self Driving RC Car or Instructables RC Car to Robot but taking a toy RC car was not easy to make a good integration.
Sites like: 40 EXCELLENT AUTONOMOUS MOBILE ROBOTS ON WHEELS THAT YOU CAN BUILD AT HOME are giving a good set of what people have built.
Before staring the project you have to choose how many wheel will have your car?
- 2 wheels is simple reduce the number of motors and offer a very good turn radius that helps avoiding obstacles
- 4 wheels looks more like a “real” car but requires 4 motors or direction wheels that make the project more complex
- 6 wheel is more for crossing obstacle than avoiding them.
Bottom line my choice is: 2 wheels. Each wheel has independent RC motor we will that in detail in a later post.
Remote Control or Autonomous:
No doubt for me a Robot Car car only be autonomous and should detect and avoid obstacle and ideally learn how to make it better.
To detect obstacles there are not many affordable choice. Radars and lasers are way to high for my budget so I choose ultrasonic distance sensor that you can get very cheap (like HC-SR04). They give you a range of 2 meters and can detect solid material if they are wide enough (not always good for chair legs).