Vacuum tube bots started in 2015. Zen was the first of the tube bots, made from a vacuum tube found at a garage sale. These tubes used to be inside of TVs, Radios, guitar amplifier, computers, and other electronics from the turn of the center to the 70’s. Some guitar amplifiers still use them today. Starting in the 60’s, Vacuum tubes started to get replaced by transistors. The same transistors that Zen’s eyes are made out of too.