Github user Wei Lin has built a scalable computing cluster comprised of $7 chips, writes Daniel Oberhaus in Motherboard.
Here is the link: https://motherboard.vice.com/en_us/article/bjpb78/diy-computing-cluster-esp32-raspberry-pi
Here is the link to Mr. Lin’s GitHub repository: https://github.com/Wei1234c/Broccoli/blob/master/notebooks/demo/Broccoli_readme_en.md