One of the debates that came out of the Liverpool Makefest 2018 was whether it would be better to use a computer eg Raspberry Pi or microcontroller such as Arduino for the control system? ….. I tried a Google search, but nowhere could I find a definitive answer.

In my mind, the Raspberry Pi, or the 'RPi', is great for complex servers or handling loads of complex data such as Ai based object recognition …… Or a complex robot with very many motors running at the same time. In contrast, the Arduino, or 'MCU', will handle simpler tasks with greater efficiency and reliability.

The RPi works with a huge operating system composed of a vast, almost indecipherable, network of inter-dependable files, using a very large amount of precious silicon. The problem here is that computers are prone to crashing due to their sheer complexity whilst a MCU, with only a few thousand lines of code, is at least one order of magnitude more reliable. The other question that was posed is that if the system, whatever it is, does crash, how long will it take to reboot?

As development of the machine continues, some of the tasks will be assigned to a small computer, the Nvidia TX2, hosting an enormous graphics processor for Ai based object recognition. More critical tasks such as navigation and detecting 'unexpected objects' will be done on MCUs. One of the major tasks is writing / finding code to get reliable communication between these devices. We might also want a simple 'watchdog' MCU to check that all the different systems are working properly. Maybe each system will constantly flash a 'heartbeat' LED (or equivalent) and the watchdog will monitor this. A small robotic arm would then move across to press the relevant reset button.