The POE-15W module is dessigned for provide the clean and stable power to the Raspberry Pi by using Power over Ethernet–enabled networks. It can help you to manage the multichannel power supply to multiple Raspberry Pi through the POE switch. For this product to be used, the network it is connected to needs to have power-sourcing equipment installed.No modification to the main Raspberry Pi board is needed for this product to work.
The POE-15W module is fitted with a small fan that is controlled by the Raspberry Pi via I2C, and the default speed is maxim when you power up. According to the temperature of the main processor on the Raspberry Pi, you should modulate the Fan speed in different applications.
- Compatible with IEEE 802.3at and IEEE 802.3af;
- Compatible with PI3B+,PI4,etc...;
- Output Voltage 5V ±0.5V;
- Peak current up to 3.5 A, continuous current 3A;
- Protection Circuitry: Transient Overvoltage, Undervoltage Lockout, Foldback Current Limiting
- CoolingFan: 30cm*30cm, Height 7mm;
- Cooling Fan Maxim Speed: 6500 RPM;
- Fan Speed is controlled by the Raspberry Pi via I2C.
Connecting your PoE HAT to the Raspberry Pi:
- Connect the Raspberry POE-15W module to the two headers (40pin + 4 pin) that are fitted on the Raspberry Pi
- Once the POE-15W module is connected, you can power the Raspberry Pi through its RJ45 network connector
- Take care when separating the from the Raspberry. Pull evenly so that it detaches from all the pins at the same rate; do not pull one end of the connector off before the other.
How to Modulate The Fan Speed
On-board PCA9633 is an I2C-bus controlled 4-channel PWM output chip. We only using the channel 0(LED 0) to control the FAN speed. For more detail, please refer to the PCA9633 usermanual .
PCA9633 is controlled by the Raspberry Pi via I2C(GPIO2 , GPIO3 on the 40 pins connector ) directly.
Step 1: Enable the IIC on Raspberry Pi
Modify the config.txt file, and add below lines and save file
$sudo nano /boot/config.txt
dtparam=i2c_arm=on #Add I2C Bus control
Step 2: Check Device
Using below command the check the poe device is available on I2C bus.
The I2C address of Poe is 0x or 0x62(7 bit address mode) and 0xC4(8 bit address mode).
- i2cdetect -y 1
Step 3: Set up Cooling Fan Speed
(1) Enable the FAN Speed Adjustment Function
Please type below command in turn to enable the adjustment function.
For more detail about the i2cset, refer to the below link: https://linux.die.net/man/8/i2cset
For the value and register description, please refer to the datasheet of PCA9633.
- i2cset -f -y -r 1 0x62 0x00 0x00
- i2cset -f -y -r 1 0x62 0x01 0x04
- i2cset -f -y -r 1 0x62 0x08 0x03
- i2cset -f -y -r 1 0x62 0x02 0xff
(2) Adjust the speed.
- i2cset -f -y -r 1 0x62 0x06 0xff
0x62: PCA9633 chip i2c address
0x06: Group duty cycle control register.
0xff: The speed value is from 0x00 to 0xff, 0x00 is correspond to the max speed, and the 0xff correspond to the minimum speed. When the value is less than 0x80, the poe module has a little noise, so the recommended the value between 0x80 to 0xff
Step 4: Detect Temperature
Type below command to get the real-time temperature of Raspberry Pi
- vcgencmd measure_temp
Type below command to continue reflash the real-time temperature of Raspberry Pi every seconds
- watch -n 1 "vcgencmd measure_temp"