Ticket Selling Machine

A Ticket Selling Machine system that simulates a ticket vending experience using a thermal printer, an LED matrix display, audio playback (DFPlayer Mini), and physical buttons. The system is split into two logic units that communicate via GPIO.

搭建中 In construction

成品 Finished product

IMG_4172.mp4 📹 演示视频 Demo video

Overview

The project consists of two independent subsystems:

1. Main Control Unit (main_control/)

   • Platform: MicroPython (ESP32).
   • Responsibilities:
     • Handling user input from physical buttons.
     • Controlling the Thermal Printer via UART (TTL).
     • Controlling audio playback via DFPlayer Mini.
     • Sending control signals to the LED Screen unit.
   • Key File: main_control/New_Main.py

2. LED Screen Display Unit (ledscreen/)

   • Platform: Arduino C++ (ESP32).
   • Hardware: HUB75 RGB LED Matrix.
   • Responsibilities:
     • Rendering the user interface (UI).
     • Displaying station lists, ticket information, and animations.
     • Communicating state changes back to the Main Control unit.
   • Key File: ledscreen/New_LED.ino

Hardware Interfaces & Pinout

1. Inter-Unit Communication (Handshake)

The two units communicate using a simple 4-wire GPIO protocol.

Main Control (Pin)	Direction	LED Screen (Pin)	Function
12 (LED_TO_PIN_1)	->	35 (LED_IN_PIN_2)	Signal "Next" / Change selection
13 (LED_TO_PIN_2)	->	34 (LED_IN_PIN_1)	Signal "Confirm" / Select
21 (LED_FROM_PIN_1)	<-	21 (LED_OUT_PIN_1)	Feedback: Selection changed (Pass)
22 (LED_FROM_PIN_2)	<-	22 (LED_OUT_PIN_2)	Feedback: Selection confirmed

Note: Pin assignments are based on New_Main.py and New_LED.ino. Always verify physical wiring.

2. Main Control Peripherals

• Thermal Printer:
  • TX: Pin 16
  • RX: Pin 17
  • Baud Rate: 115200
• DFPlayer Mini:
  • TX: Pin 26
  • RX: Pin 27
• Buttons:
  • Button 1 (Next): Pin 4 (Pull-down)
  • Button 2 (Confirm): Pin 5 (Pull-down)

3. LED Screen Peripherals (HUB75)

• Standard HUB75 pinout (R1, G1, B1, R2, G2, B2, A, B, C, D, E, CLK, LAT, OE) defined in New_LED.ino.

Directory Structure

• main_control/: MicroPython source code.

  • New_Main.py: Entry point for the main controller. Contains the state machine for button presses, printer commands (print_text), and audio triggers.
  • dfplayermini.py: Driver library for the MP3 module.
  • .mpyproject.json: Configuration for Pymakr/MicroPython tools.

• ledscreen/: Arduino/C++ source code.

  • New_LED.ino: Main Arduino sketch. Handles the display state machine (INIT, CHECK, PICK), drawing logic (draw_ticket_interface), and randomization.
  • Data.h: Bitmap data for fonts and images (e.g., station_list_matrixData).
  • ESP32-HUB75-VirtualMatrixPanel_T.hpp: Driver/wrapper for the LED matrix.

Development & Usage

Main Control (MicroPython)

1. Environment: VS Code with Pymakr extension or similar MicroPython tools.
2. Upload New_Main.py and dfplayermini.py to the board.
3. New_Main.py runs in a while True loop and will run automatically on boot if renamed to main.py or called from it.

LED Screen (Arduino)

1. Environment: Arduino IDE or PlatformIO.
2. Dependencies:
   • ESP32-HUB75-MatrixPanel-I2S-DMA library.
   • Adafruit GFX (required by the matrix library).
3. Compile and upload New_LED.ino to the ESP32 driving the matrix.

Notes

• Printer Commands: New_Main.py contains a comprehensive set of byte sequences for controlling the thermal printer (formatting, Chinese characters, barcodes). Do not modify the byte constants unless you know the specific ESC/POS commands.
• Randomization: The "Pick" feature (ticket lottery) uses a random seed to simulate a spinning roulette before settling on a station.

License

MIT License. See LICENSE.