Overview
This device is an interface board that reads and counts signals from different brands of ticket/token dispenser modules (TL-001, DL-1275, DL-4, LK009P) and re-sends the same number of pulses on its output. Built around an ESP32-C3, it electrically isolates both input and output signals with optocouplers; the 12V power input is protected by a PTC fuse, a Schottky diode, and TVS diodes, then stepped down to 5V through an isolated DC-DC converter. DIP switches select both the connected module type and the NO/NC sensing mode, with live counts shown on a 1.3-inch OLED display.
Goals and Objectives
Our customer wanted an intermediary device that could digitally count and log the physical pulses coming from different brands of dispenser modules, reducing reliance on paper tickets. Our goal was to design a device compatible with multiple module brands, electrically safe (isolated and protected), and able to give live feedback.
Development Process
We studied the signal timing of four different dispenser modules and set separate input/output delay values for each. We isolated the input, output, and ready signals individually with PC817 optocouplers; protected the 12V power input with a PTC fuse, Schottky diode, and TVS diodes, then stepped it down to 5V through an isolated DC-DC module. We wrote the ESP32-C3 firmware to read the pulses and display the live count on the OLED screen, re-sending the same pulse count on the output once a read cycle finished; we designed both the schematic and the board ourselves in EasyEDA.
