Will this PoE HAT work with the older Raspberry Pi 3B or Pi Zero?

No, this PoE HAT requires the specific 4-pin PoE header, which is only available on the Raspberry Pi 3B+, Raspberry Pi 4B, and newer compatible models.

What is the difference between this PoE HAT (B) and a standard PoE splitter?

Unlike a bulky external splitter, this HAT mounts directly onto the Raspberry Pi's GPIO pins for a seamless, compact fit, and it includes an OLED screen and active cooling fan.

How do I program the cooling fan to turn on automatically based on temperature?

You can set the physical switch on the board to "P0" and use a simple Python script via the I2C interface (PCF8574 chip) to trigger the fan when the CPU reaches a specific temperature.

Can I bring my Raspberry Pi to your Hong Kong store to test the HAT?

Yes, you are highly encouraged to bring your Raspberry Pi 3B+ or 4B to our Sun Cheong Computer Co. Ltd. physical store in Sham Shui Po to verify fitment and functionality before purchasing.

Will the OLED display conflict with other I2C devices I want to connect?

No, the SSD1306 OLED and the PCF8574 IO expander have specific I2C addresses, allowing you to safely connect other I2C sensors to the Raspberry Pi without address conflicts.

Waveshare PoE HAT (B) for Raspberry Pi 3B+/4B

Name: Waveshare PoE HAT (B) for Raspberry Pi 3B+/4B | OLED & Fan
Brand: Waveshare
SKU: 21PS002256
Price: 159.0 HKD
Availability: InStock

Short Product Description

The Waveshare PoE HAT (B) is a professional-grade Power over Ethernet expansion board designed specifically for the Raspberry Pi 3B+ and 4B. By utilizing an 802.3af-compliant network switch, this HAT delivers both a stable 5V 2.5A power supply and a network connection through a single Ethernet cable. Featuring a built-in 0.91" OLED display for real-time system monitoring and an active cooling fan, it is the ultimate solution for compact server racks and smart home hubs. Available in-stock at Sun Cheong Computer Co. Ltd. (新昌電腦有限公司) in Sham Shui Po, our 20+ years of technical expertise ensures you get the best hardware for your IoT deployments.

Key Features

Single-Cable Solution: 802.3af-compliant PoE capability provides both network and power via one Ethernet cable, ideal for remote installations.
Built-in OLED Display: The 0.91" white OLED screen provides real-time readouts of IP addresses, CPU temperatures, and fan status.
Programmable Cooling Fan: Keeps your Raspberry Pi 3B+/4B cool under heavy loads, with options for auto-run or I2C software control.
Fully Isolated SMPS: The switched-mode power supply ensures safe, stable, and interference-free 5V 2.5A power delivery to your board.
I2C IO Expansion: Integrates a PCF8574 chip to manage the fan and provide extra expansion pads without occupying standard GPIO pins.

Full Product Description

Simplify Your Setup with 802.3af Power Over Ethernet

Deliver both stable power and a high-speed network connection through a single Ethernet cable to eliminate desktop cable clutter. The Waveshare PoE HAT (B) features a fully isolated switched-mode power supply (SMPS) that safely steps down 37V-57V PoE input to a clean 5V 2.5A output for your Raspberry Pi. This makes it incredibly easy to deploy Raspberry Pi clusters, digital signage, or remote security cameras in locations where standard AC wall outlets are unavailable.

Real-Time System Monitoring via 0.91" OLED

Keep track of your Raspberry Pi's vital statistics instantly on the built-in 128x32 pixel OLED screen. Driven by the reliable SSD1306 controller, this crisp white display can be programmed to show your device's IP address, CPU temperature, and fan status in real-time. This visual feedback is invaluable for headless server setups, allowing IT administrators to diagnose network issues or thermal throttling without needing to SSH into the system.

Intelligent Active Cooling System

Prevent thermal throttling during heavy workloads with the programmable onboard cooling fan. The HAT features a physical switch that allows you to set the fan to run automatically upon power-up or configure it for programmable control via the I2C bus. By utilizing the integrated PCF8574 IO expander, the fan operates efficiently without consuming your Raspberry Pi's primary GPIO pins, ensuring your processor stays cool even during intensive edge-computing tasks.

Pro Tip from Our Technicians

Ensure your network router or switch is actively 802.3af-compliant before connecting this HAT to avoid power delivery failures. Our Sham Shui Po DIY specialists remind you that standard "passive PoE" injectors will not work and may damage the board. Additionally, because the OLED and fan control utilize the I2C interface, you can easily daisy-chain other I2C sensors using the extra expansion pads provided on the board.

Technical Specifications

Compatibility: Raspberry Pi 3B+ / 4B (Requires 40-pin GPIO and 4-pin PoE header)
PoE Standard: 802.3af-compliant Power Over Ethernet
Power Input: 37V ~ 57V DC
Power Output: 5V 2.5A DC
Display Type: 0.91" OLED (White)
Display Resolution: 128 x 32 pixels
Display Driver: SSD1306 (I2C Interface)
IO Expander: PCF8574 (Provides fan control and extra pads)
Dimensions: 56.5mm x 65.0mm

Delivery Options

Local delivery within Hong Kong and in-store pickup.
Free shipping for orders of HK$400 or above; HK$35 shipping fee for orders below HK$400.
Shipped by SF Express, usually dispatched the same day for orders confirmed before 6:00 PM (Mon–Sat).
Estimated delivery time: 1–3 business days after dispatch (Hong Kong).
In-store pickup details (location and time) will be confirmed by email or phone message.
Delivery times are estimates and may be affected by weather or unforeseen circumstances.

FAQ Section

Will this PoE HAT work with the older Raspberry Pi 3B or Pi Zero?No, this PoE HAT requires the specific 4-pin PoE header, which is only available on the Raspberry Pi 3B+, Raspberry Pi 4B, and newer compatible models.
What is the difference between this PoE HAT (B) and a standard PoE splitter?Unlike a bulky external splitter, this HAT mounts directly onto the Raspberry Pi's GPIO pins for a seamless, compact fit, and it includes an OLED screen and active cooling fan.
How do I program the cooling fan to turn on automatically based on temperature?You can set the physical switch on the board to "P0" and use a simple Python script via the I2C interface (PCF8574 chip) to trigger the fan when the CPU reaches a specific temperature.
Can I bring my Raspberry Pi to your Hong Kong store to test the HAT?Yes, you are highly encouraged to bring your Raspberry Pi 3B+ or 4B to our Sun Cheong Computer Co. Ltd. physical store in Sham Shui Po to verify fitment and functionality before purchasing.
Will the OLED display conflict with other I2C devices I want to connect?No, the SSD1306 OLED and the PCF8574 IO expander have specific I2C addresses, allowing you to safely connect other I2C sensors to the Raspberry Pi without address conflicts.

Target Users / Applications

IT administrators deploying headless Raspberry Pi clusters in server racks requiring neat, single-cable power solutions.
Digital signage installers mounting Raspberry Pi 4B units behind TVs where AC power outlets are unavailable.
Smart home enthusiasts building Home Assistant hubs that require active cooling and real-time IP address monitoring.