FanPico User Manual
FanPico is a generic programmable (PWM) fan controller. Altough it was initially created to be used inside a PC, it can be used for other purposes and does not necessarily require any fan PWM signals (from motherboard). It could be easily programmed to control fan speeds based on temperatures measured by one or more temperature sensors.
| Connector | Description | Notes |
|---|---|---|
| MB FAN1 | Fan Signal Input from motherboard | Can be used to power FAN1 and/or FAN5 (and FanPico itself) |
| MB FAN2 | Fan Signal Input from motherboard | Can be used to power FAN2 and/or FAN6 |
| MB FAN3 | Fan Signal Input from motherboard | Can be used to power FAN3 and/or FAN7 |
| MB FAN4 | Fan Signal Input from motherboard | Can be used to power FAN4 and/or FAN8 |
| AUX POWER | Auxiliary Power Input | Can be used to power any of the FAN outputs (and FanPico itself) |
| SENSOR1 | Remote Temperature Probe | K-type probe 10k or 100k nominal resistance (JST 2.5mm connector) |
| SENSOR2 | Remote Temperature Probe | K-type probe 10k or 100k nominal resistance (JST 2.5mm connector) |
| FAN1 | Fan Output | |
| FAN2 | Fan Output | |
| FAN3 | Fan Output | |
| FAN4 | Fan Output | |
| FAN5 | Fan Output | |
| FAN6 | Fan Output | |
| FAN7 | Fan Output | |
| FAN8 | Fan Output | |
| Serial (TTL) | Serial Console | This is for 3.3V TTL level serial connector (not RS-232!) |
| SPI | I2C / SPI | Pins shared between SPI and I2C bud. Current firmware does not support SPI, but this could be used to connect I2C bus devices |
| USB | RPi Pico USB | USB Serial Console for programming and monitoring. |
| Jumper | Name | Description |
|---|---|---|
| JP1 | Main Power | Main Power Input selection(AUX POWER connector / MB FAN1 connector) |
| JP2 | FAN1 Power | FAN1 Power Source selection (MB FAN1 connector / AUX POWER connector) |
| JP3 | FAN2 Power | FAN2 Power Source selection (MB FAN2 connector / AUX POWER connector) |
| JP5 | FAN3 Power | FAN3 Power Source selection (MB FAN3 connector / AUX POWER connector) |
| JP4 | FAN4 Power | FAN4 Power Source selection (MB FAN4 connector / AUX POWER connector) |
| JP6 | FAN5 Power | FAN5 Power Source selection (MB FAN1 connector / AUX POWER connector) |
| JP7 | FAN6 Power | FAN6 Power Source selection (MB FAN2 connector / AUX POWER connector) |
| JP8 | FAN7 Power | FAN7 Power Source selection (MB FAN3 connector / AUX POWER connector) |
| JP9 | FAN8 Power | FAN8 Power Source selection (MB FAN4 connector / AUX POWER connector) |
| JP10 | SENSOR1 Type | Select between 10k ohm and 100k ohm NTC thermistor. |
| JP11 | SENSOR2 Type | Select between 10k ohm and 100k ohm NTC thermistor. |
FanPico (unit itself) can be powered from the first motherboard fan input (MB FAN1) or alternatively from the Auxiliary ("Floppy") power connector (AUX POWER).
Use jumper JP1 (Main Power) to select the power source.
FanPico typically consumes under 100mA from 12V Input. Power consumption can wary significantly depending on if using Pico or Pico W (WiFi can use significant amount of power) and if using OLED module or not.
In power calculations it is probably best budget 200mA for the FanPico itself.
AUX POWER input is meant to draw up to 3A (there is PolyFuse that will start limiting if usage goes over).
MB FAN inputs should not draw more than the corresponding motherboard output is rated for.
To be sure that all Fans will get enough power and not too much current is drawn from any of the inputs (AUX POWER or MB FAN inputs) it is good to calculate (maximum) power consumption for each input.
With modern motherboards (that generally provide at least 1A on each motherboard fan output) and modern fans (that typically rated around 0.3A at 12V) FanPico can be safely powered from just only motherboard outputs. But it is still good idea to make sure not too much strain is put on motherboard fan outputs.
Following "worksheet" could be used to determine that there is sufficient power available:
| Input | Input Max Current | Output 1 | Output 1 Current | Output 2 | Output 2 Current | FanPico Curent | Output Max Current |
|---|---|---|---|---|---|---|---|
| MB FAN1 | FAN1 | FAN5 | 0.2A | ||||
| MB FAN2 | FAN2 | FAN6 | N/A | ||||
| MB FAN3 | FAN3 | FAN7 | N/A | ||||
| MB FAN4 | FAN4 | FAN8 | N/A |
- First fill in the "Input Max Current" column based on the motherboard documentation
- Then fill in the fan max current for each FAN (that is not set to be powered from "AUX")
- Finally fill in 0.2A for "FanPico Current" on first row, if powering FanPico from MF FAB1 connector.
- Calculate "Output Max Current" by adding up the "Output 1 Current", "Output 2 Current", and "Fan Pico Current"
- Finally, check that Output Max Current is never higher than the Input Max current.
If output max current is higher for some MB FAN input, then consider powering one of the FANs from AUX POWER or using lower power FAN, etc...
AUX POWER input has 3A fuse protecting it. So it is good idea to make sure that the planned fan configuration will not end up using more than that.
Following "worksheet" could be used to calculate power usage:
| Connector | Max Current | Notes |
|---|---|---|
| FAN1 | ||
| FAN2 | ||
| FAN3 | ||
| FAN4 | ||
| FAN5 | ||
| FAN6 | ||
| FAN7 | ||
| FAN8 | ||
| FanPico | Enter "0.2A" if powering FanPico from AUX POWER (JP1 set to "AUX") |
- Enter max current for each FAN connector that is configured to be powered from "AUX" (otherwise leave empty or enter zero)
- Calculate total current by adding up all the values on second column.
- Check that the result is less than 3A
If result is over the max current for AUX POWER connector, consider powering some of the fans from MB FAN inputs or using fans with lower power consumption.
FanPico PCBs have 4 mounting holes that are grounded, so it's safe to mount it directly to a PC case using metal screws/mounts. But it is fine to use plastic mounts/screws if desired, as MBFAN connections or AUX POWER connection will connect the ground on FanPico to the computer ground.
When installing FanPico following connections are typically needed:
- MB FANs: One or more motherboard FAN outputs (4-pin PWM outputs) connected, to provide power and PWM signals to drive fans. NOTE, it is possible to use FanPico without using these connections if planning on controlling fans from temperature sensors or using a program/script to control fan speeds using the SCPI command set.
- AUX POWER: If there is not enough power provided by motherboard FAN connectors (outputs), this can be used to power Fans connected to FanPico.
- USB: This is typically connected to motherboard USB 2.0 header for programming and monitoring purposes.
- FANs: One or more 4-prin PWM fans connected to the FAN ports.
This examples shows the process of setting up FanPico on a PC that has 5 case fans and 1 CPU fan to control all the fans.
- Motherboard: ASUS Prime X570-Pro
- Using 4 PWM Fan outputs (all rated 1A each): "CPU_FAN", "CHA_FAN1", "CHA_FAN2", "CHA_FAN3"
- Using USB2.0 pin header for FanPico "console": "USB34"
- Fans
- Top Exhaust: 2 x Noctua NP-14s redux 1500 PWM (0.20A)
- Front Intake: 2 x Scythe KF1425FD12SR-P 1200 PWM (0.12A)
- Rear Exhaust: 1 x Scythe KF1425FD12SR-P 1200 PWM (0.12)
- CPU Cooler: Noctua NF-A15 1500 PWM (0.13A)
- FanPico 0804D (or 0804)
- Temperature Sensors: generic 10k Ohm NTC with JST 2.5mm connector (for measure temperature of air intake and exhaust)
- PWM extension cables (4-pin female to 4-pin male)
- PWM "motherboard" cables (4-pin female to 4-pin female)
- Motherboard USB 2.0 header to Micro USB cable (alternatively generic motherboard USB2.0 cable to USB-A and regular Micro-USB cable works)
- Motherboard standoffs (and some M3 lock nuts for securing them)
If using FanPico without a display (or using cable to relocate the display) it is often easies to install in on the "back side" of typical PC case. But if using it with nice OLED module it is nice to have unit visible through transparent side panel.
On our example system there is plenty of "free" space beside the 5.25" drive bays. So drilling two 1/8" holes and installing brass motherboard standoffs (using M3 locknuts so they won't come loose):
Cabling can be tricky, since depending on FanPico mounting location and location of motherboard connectors, chassis fans, etc. usually means that large number of different cable lengths is needed.
Connecting motherboard FAN (outputs) to FanPico "MB FAB" inputs to provide power and fan PWM input signals (as well as tachometer output signals back to motherboard).
These connections require 4-pin Female to Female cables. These cables exist but can be hard to find. So one option is to build your own cables from scratch. If you're comfortable crimping your own connectors, easies is to cutoff the 4-pin male connector and replace it with 4-pin female connector.
Another alternative is to use two "extension" cables and cutoff the 4-pin male connectors, then solder the two cables together.
In this example we're running cables as follows:
| Motherboard Connector | FanPico Connector |
|---|---|
| CPU_FAN | MBFAN1 |
| CHA_FAN1 | MBFAN2 |
| CHA_FAN2 | MBFAN3 |
| CHA_FAN3 | MBFAN4 |
Connect chassis fans to "FAN" connectors on Fan Pico.
This is straightforward process, simply connect fans directly (if fan's own cable is long enough) or using extension cables as needed.
In this example we connect fans as follow (fans can be connected to any output):
| Fan Location | FanPico Connector |
|---|---|
| CPU Cooler | FAN1 |
| Rear (Exhaust) Fan | FAN2 |
| Front (Intake) #1 | FAN5 |
| Front (Intake) #2 | FAN6 |
| Top (Exhaust) #1 | FAN7 |
| Top (Exhaust) #2 | FAN8 |
Temperature sensors can be used to monitor temperature inside the PC.
In our example we decided to monitor intake air temperature and exhaust air temperature.
| Sensor Location | FanPico Connector |
|---|---|
| Behind front intake fan | SENSOR1 |
| Behind rear exhaust fan | SENSOR2 |
USB (Console) connection is meant to be connected on one of the motherboard USB 2.0 connectors so that it is easy to configure and monitor FanPico.
