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This video was inspired by the teachers and students of the STEM Club at Holroyd High School in Sydney NSW Australia during STEM robotic sessions with the Lego ev3 robot kit.
I spent many hours trying to get the Lego ev3 to work for the STEM Club but there were many failures including failure to update the ev3 firmware and failure of the wifi coms on ev3 to maintain coms with the internet and local wifi network. On a couple of occasions I could get the wifi to works and even imported a Debian Linux operating system called ev4dev but it was not reliable and is now not supported.
There must be a better solution than using an obsolete ev3 which has seem little improvements since it was killed off by Lego in Dec 2022.
This project explores a better solution and one that is current. It uses the Raspberry Pi Model 4 with a Raspberry Pi Build HAT to control the Lego Technic motors on robots. It goes much further and adds a camera and remote control. No problems with motor control, wifi, remote control or multi tasking and there is even a potential to use a real time operating system called ROS2 for better performance. All of this will be used for a Mars Rover with remote and autonomous control. There is even the potential to port the software to node-red using the low level motor control software where a Raspberry Pi Pico 2040 is used together with serial coms to Raspberry Pi.
This project is based on the BuildMeCar robot construction kit from Waveshare and it is a very low cost package that replaces the expensive Lego Spike motors with cheaper low powered Lego Technic medium motors. There are no sensors supplied with this kit.
The kit also has LiPo battery, charger, camera and all the Lego parts needed to construct a mobile robot with mecanum wheels. All of the software is available as an image ready to be transferred to a micro SD card and all of the software and drivers are already installed on this image.
I made some changes to this kit. First I did not like the chassis construction - it is crude and takes a lot of time to make it. My version can be built within a few minutes and uses more recent Lego Technic plates with two levels - one dedicated to the battery and motors and the other for the Raspberry Pi and camera. It is also easy to update from two wheel to four wheel drive and extra sensors such as Grove sensors can be supported on the 19x11 Lego Technic plates.
The demos on the video show the finished construction and desktop unit testing. Next version is for mars and to test rover navigation there.
I will also explore adding more sensors to the rover has the Raspberry Pi Build Hat only has four ports and if you use these just for motor control there is nothing left over for sensors. I will explore adding a Seeed Studio Grove HAT to the rover so many other sensors can be added. Only issue might be if they both use UART coms to communicate with Raspberry Pi.
References:
BuildMecar Kit, Smart Building Block Robot with Mecanum Wheels, 5MP Camera, Based on Raspberry Pi Build HAT ( www.waveshare.... )