The detail that caught me off guard is that this thing actually ran at a real panipuri stall for about three hours, with event attendees filling their own shells at the automated nozzles. A hobby controller project surviving a full shift of hungry crowd traffic is not the usual outcome, and that alone makes it worth a close look.
The way it is put together is refreshingly simple. An IR proximity sensor sits near the dispenser nozzle, and placing a puri beneath it sends a low signal to the Arduino. The code in main.cpp checks digitalRead on the sensor pin at D4 and toggles a relay on D5, wired so LOW means on and HIGH means off. That relay, a 5 volt module, switches a submersible pump that pushes liquid through tubing into the shell, drawing green flavored liquid from a tall jar. Jumper wires and a power supply round out the parts list.
There are two versions, which I appreciate. One runs on espidf 6.1 code, and the other uses Arduino Core for ESP, so it fits this forum nicely. The larger variant is the one that turns heads: a two-nozzle dispenser mounted onto a covered tub, clearly meant for busy gatherings rather than a bench test.
The rough edge is calibration. The IR sensor behaved unpredictably at first and getting the detection distance right took real effort. Three hours of stall duty is a solid result, but the sensor tuning seems like the part worth watching as the build matures. Given that the maker's daughter is behind this at fourteen, the trajectory looks very promising.
Project by Rajeev Sharma. Watch it on their YouTube channel: