Last year I stated with the disc box robot. The brain of the bot is a Raspberry Pi 3 Model B with Raspbian Jessie. The mecanum-car uses mecanum wheels to drive around which are very special wheels. With the mecanum wheels the robot is able to strafe – move from side to side. Each wheel needs to be controlled separately to control the moving’s of the bot. The mecanum bot uses four DC gear motors to spin the wheels. For controlling the four DC motors I installed two motor drivers. I am using two L298 H-bridges to control the four DC motor separately from each other.
This was enough theory on how to deal with a bot with mecanum wheels. The video below shows the robot driving around in my office the first time.
This video shows the bot driving around in my office.
The next picture shows the robot from inside with the Raspberry Pi, the two motor drivers, a step-down converter and a Raspberry Pi camera.
I published a list with all the electronic components I typically use for more bots.
Raspberry Pi robot-car component list:
If I could awaken you interest how to build such a robot with a Raspberry Pi computer as central controlling unit you will find a list of components on my blog to help you. The component list is an overview of electronic components or ready to assemble kits which I used by myself and which I could recommend with good conscience. I used most of the components in my own projects and checked the functionality and compatibility with a Raspberry Pi.
This is the link to the component list: component list
In the back of the bot the two motor drivers are hooked up. On the right side next to the motors drivers the step-down converter is installed to supply the Raspberry Pi with 5 V. The DC motors are 12 V motors and I use two 7.2 V accus in series with 14.4 V to power the DC motors.
On top of the robot I installed a Raspberry Pi Sense HAT with different sensors. Actual I am not using any of the sensors to control the movements of the bot like I did in this tiny robot-car <link>. But I will enhance my Python programs for controlling the four DC motors and mecanum wheels in a smooth way to enable the botto drive special turns.
E-Book – build a remote controlled robot with a Raspberry Pi
With this e-book you can create step by step, your unique remote controlled car. The interaction of hardware, electronics and software are explained with the help of concrete examples. This makes it easy to understand the more complex parts of the project.
The e-book is available as PDF.
The e-book costs 14.90 USD inkl. 19% VAT. (Germany).
When ordering from other countries the gross price may vary since then other VAT rates apply.
Software: Python control program
I already developed a Python program to control one motor driver. Now I enhanced this program to deal with two motor drivers. It was not really difficult but to use the correct GPIO pins out of 12 was the challenge.
I also enhanced the Python program with which I control the movements of the bot . The program actual has no gui and you have to start it in the terminal. By pressing keys on the keyboard the robot is steered. As you see in the picture the interface informs you about the usage of the keys and the speed of each motor.
If you would like to download the program to control the two motor drivers and the interface with which you could drive the mecanum-car around both programs are available for download: python program to control the mecanum robot