Programming the Coin Acceptor

The ATM uses a programmable HX-616 pulse coin acceptor. It must be taught which coins to accept and how many pulses to emit for each, before it is wired to the ESP32.

Warning

Adjust the output voltage of the step-up converter before connecting the coin acceptor — it runs on 12 V. Powering it incorrectly can damage the unit.

How pulse counting works

The coin acceptor signals each recognised coin by emitting a number of pulses on its “Coin” line (wired to GPIO 17 — see Wiring & Pinout). The firmware counts those pulses with a debounced interrupt and maps the pulse count to a cent value. When you program the acceptor, assign each coin a distinct pulse count so the firmware can tell them apart.

Programming guides

Follow one of these detailed guides to program the acceptor for your coins:

• Coin Acceptor Programming Guide (English)

• Coin Acceptor Programming Guide (German)

Once programmed, wire the acceptor and its blocking MOSFET as described in Wiring & Pinout.