What do you do when the quote to fix your bowling alley's scoring comes back at $80,000?
A Hacker News poster going by section33 bought an abandoned 8-lane center and got exactly that number, with parts alone running about $4,000 per lane pair. Then he opened up the pinsetters. The 70-year-old machines are almost purely mechanical, and the expensive "advanced" controller they were paying for mostly just closed one relay to kick the pinsetter. That is a job for a $6 microcontroller, not a six-figure cabinet. His replacement, OpenLaneLink, lands somewhere around $200 to $400 per lane pair, or roughly $1,600 for the whole house.
How the wiring actually works
Each lane pair gets an ESP32 node. The node watches IR break-beam sensors to detect a ball crossing the foul line and the pins falling, reads machine state through optocouplers so the 1950s wiring never touches a 3.3V GPIO pin directly, and fires a relay to trigger the pinsetter cycle. Optocoupler isolation is the part worth copying: bowling machines run mains-adjacent voltages and back-EMF from those motor contactors will happily kill an ESP32 that is tied straight to them.
The nodes talk over ESP-NOW, Espressif's connectionless 2.4 GHz protocol that skips the whole Wi-Fi association handshake, so a pin-fall event reaches the gateway in single-digit milliseconds without a router in the loop. RS485 sits underneath as a wired fallback, which is the right call in a metal-heavy building full of motors. A gateway node connects over UART to a Raspberry Pi running Redis and a scoring state machine, and from there it is a normal web stack: middleware, React, and WebSocket pub-sub. Any front-end dev on the team can build a lane UI without touching firmware.
Try a smaller version of this
You do not need a bowling alley to practice the pattern. Wire an IR break-beam pair to two ESP32s, send the trip event over ESP-NOW, and push it to a Pi over UART at 115200 baud. That is the same sensor-to-mesh-to-server chain, minus the pinsetters. Add a PC817 optocoupler on the input side and you have handled the isolation lesson too. Watch out for one gotcha: ESP-NOW and Wi-Fi station mode must share a channel, so lock the channel explicitly if your gateway is also online.
The full architecture write-up, including planned DMX light shows and tap-to-pay kiosk bowling, is in the Hacker News thread. The author says hardware, firmware, and software will be open sourced once it stabilizes.
Originally published on blog.circuit.rocks.
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