ESPHome Component and Package for the Douk Audio VFD4 Vintage VFD Clock.
This project centers on reverse-engineering the Douk Audio VFD4 Vintage VFD Clock, which features an ESP8266 microcontroller and a stunning Soviet-era IVL2-7/5 vacuum fluorescent tube (VFD) display. Using ESPHome, the clock can be integrated effortlessly into a smart home setup via Home Assistant or MQTT.
The clock includes NeoPixel LEDs and a DS1302 real-time clock (RTC). The display is controlled by an HV5812WG-G high-voltage shift register, requiring multiplexing logic for proper operation. After reverse-engineering the display connections and wiring, a custom ESPHome component was created to enable full functionality.
- ESP8266-based microcontroller
- Two physical buttons for user interaction
- IVL2-7/5 VFD tube display driven by an HV5812WG-G high-voltage shift register
- NeoPixel LED support with 68 LEDs:
- 60 LEDs arranged in an outer ring around the clock PCB
- 8 LEDs beneath the high-voltage shift register
- DS1302 Real-Time Clock (RTC) for accurate timekeeping
- Auto-Brightness Control: Currently non-functional. If you know how this feature could be implemented, contributions or suggestions are highly encouraged!
The HV5812WG-G is a 20-channel high-voltage shift register designed for applications that require the control of multiple high-voltage outputs. It operates using a serial data input and can shift data through the register with a clock signal. The key features include:
- Output Voltage: Up to 80V per channel, suitable for driving high-voltage VFD tubes.
- Data Input: 3.3V or 5V logic-level compatible, allowing direct connection to the ESP8266.
- Daisy-Chaining Support: Multiple shift registers can be chained for larger applications.
- Latch Enable: Ensures stable output values when data is shifted through the register.
In this clock, the HV5812WG-G is used to drive the IVL2-7/5 tube segments and multiplex its digits. This configuration enables the ESP8266 to control the high-voltage display with minimal GPIO usage.
The IVL2-7/5 is a Soviet-era vacuum fluorescent display (VFD) tube designed for numeric and symbolic displays. It consists of seven-segment digit characters and several additional symbols. Key characteristics include:
- Operating Voltage:
- Filament (cathode): Typically 1.2–2.0V AC or pulsed DC.
- Grid and Anode (segment): Requires 20–60V for proper illumination.
- Multiplexing Capability: The tube supports multiplexing, reducing the number of driver lines needed.
- Brightness: Controlled by the duty cycle of the multiplexing signals.
The IVL2-7/5 tube is connected to the HV5812WG-G shift register, which controls the high-voltage segments and grids. This setup allows the ESP8266 to illuminate specific segments by sending appropriate data through the shift register and synchronizing with the tube’s multiplexing requirements.
| ESP GPIO | Function | PCB Pin No. |
|---|---|---|
| GPIO-1 | TX / SET | 3 |
| GPIO-3 | RX / ADD | 5 |
| GPIO-5 | DS Clock | - |
| GPIO-4 | DS IO | - |
| GPIO-0 | DS CE | 4 |
| GPIO-2 | LED Ring | 6 |
| - | ESP VCC | 1 |
| - | ESP EN | 2 |
| - | ESP GND | 8 |
To flash the ESP8266, follow these steps:
- Remove the glass cover and detach the PCB from the wooden casing.
- Connect a serial programmer to the PCB pinouts as follows:
- Pin 3 (TX) → Programmer RX
- Pin 5 (RX) → Programmer TX
- Pin 1 → 3.3V on the programmer
- Pin 8 (GND) and Pin 4 (GPIO_0) → Programmer GND
- Install ESPHome on your computer.
- Configure the YAML file for your device. You can refer to the provided
vfdclock_example.yamlfile for guidance. - Run ESPHome and flash the firmware using the serial connection.