They are designing the chip of the robot to adjust movement based on information they can gather from the mushroom when it responds to stimuli, not the other way around. The mushroom is not in control of the robot.
As far as I can tell? No, but I just did a search of the onimbus for some keywords. The mental image feels very Adamsish though, doesn't it? I may have unconsciously plagiarized it from somewhere. Props to you if you can find the source. Maybe it's a Pratchettian quote? Or Giamanic?