We’ve seen a few simple computers recently, but none have had the educational and practical strengths of the pπ, created by Subir Bhaduri and reported on by Hackaday, which combines a Raspberry Pi 4 and a projector in a bespoke sheet metal case. The whole thing can be carried around on the back of a motorbike, to allow schoolchildren in India to catch up on lessons missed due to the disruptive effects of the Covid-19 pandemic.
Schools in India have been closed for more than two years, and while online classes have been offered, they’re a tricky sell in a country where the technology needed to attend them is available to less than 10% of the population, and one smartphone shared between five or six children. The need for a computer that could be seen by a whole form of children at once led to Bhaduri, a prototype maker from Pune in India, trying to build “the most simple computer I could imagine”. One unit costs the equivalent of $230.
The aims of the project were that the computer should be low cost, portable, and rugged. It needed to survive transport and handling, as teachers took them to their schools in remote areas. The computer’s casing has a built-in carrying handle, and its laser-cut sheet-metal case means it can take a bump or two – Bhaduri shows a photo on his Hackster page of two of the units strapped to the back of a Honda Splendor motorbike with bungees.
Apart from the Raspberry Pi 4 board, which is controlled by a keyboard and mouse over USB (which also connects a webcam), the most important part of the pπ is its projector, the lens of which sticks out of the casing and is covered with a lens cap when not in use, a weakness in the design Bhaduri is working on. The output is also quite dim, so classrooms have to be darkened in order to use it, but using enough LCD screens for a whole group of kids would be prohibitively expensive, and the projector produces a large enough image for everybody to see. Power is delivered directly to the Pi 4’s GPIO pins, as changing to USB-C following an earlier Pi 3B+ design proved difficult.
The pπ is open-source, and all you need to build your own can be found at Bhaduri’s GitLab repository, where you’ll also find background information and a bill of materials. Version 1.3 of the pπ is being tested in the field right now, with ideas and fixes for 1.4 being collated.