fiber-optic-serial-dat
Sending UART Serial Data over Plastic Optical Fiber (POF)
Using plastic optical fiber (POF) to transmit UART serial data provides EMI resistance and electrical isolation. Here's how to do it:
🧰 What You Need
- Plastic Optical Fiber (POF) – typically 1mm core, 650nm red LED compatible.
- Optical Transceivers – e.g., Avago HFBR-1521 (TX) and HFBR-2521 (RX)
- Microcontrollers or USB-to-UART adapters
- Resistors and capacitors – per the transceiver datasheet
- Logic level shifters – if voltage levels don't match
🔌 Basic Wiring Overview
TX Side (UART → Optical)
- Microcontroller UART TX → Optical Transmitter (e.g., HFBR-1521)
- Power (3.3V or 5V)
- Current-limiting resistor for LED (per datasheet)
RX Side (Optical → UART)
- Optical Receiver (e.g., HFBR-2521) → UART RX
- Power supply
- Pull-up resistor on RX output (if open collector)
🛠️ Wiring Example with HFBR-15X1 / 25X1
-
TX Module (HFBR-1521):
- Anode → Vcc through resistor
- Cathode → UART TX (possibly via transistor)
-
RX Module (HFBR-2521):
- Output → UART RX with pull-up resistor to Vcc
⚠️ Note: These modules output non-inverted logic compatible with UART.
⚙️ UART Settings
- Baud Rate: up to 250 kbps recommended for stable operation
- Settings: Standard 8N1 (e.g., 9600 8N1)
📏 Max Transmission Distance
- Up to 20 meters for typical POF setups
🧪 Testing
- Connect USB-to-UART adapter to one side, microcontroller or another adapter to the other
- Use serial terminal (PuTTY, Arduino IDE, etc.) to send test messages
- Perform loopback or echo tests