DIJ Pocket Turbo Jet Fan

I built this compact and powerful fan using electronic components from AliExpress.
Important: This project is intended only for users with experience in electronics, soldering, and battery handling. I take no responsibility for any damage or injury.

The setup is optimized for 4S LiPo batteries, but 2S, 3S, or even 5S/6S might also work (untested). In my experience, 4S provides the best performance.

Components used

Battery
I recommend the Ovonic 4S 1550 mAh RC battery – it works reliably under load.
I initially tried 18650 cells, but the voltage dropped too quickly under load.

ESC (Electronic Speed Controller)
Use an ESC with integrated BEC – this allows you to power the Arduino and provides more stable control.
I used a 30 A ESC for 2–4 S, but 20 A should also be sufficient.

Jet Fan
I used this model:
https://de.aliexpress.com/item/1005006433888205.html
I desoldered the onboard PCB and connected the ESC directly to the three motor wires.

BMS (Battery Management System)
Choose a BMS with balancing port – it makes battery integration easier and ensures better cell health.
A 20 A model with balancing works fine.

Charging Board
I used a bidirectional USB-C board:
https://de.aliexpress.com/item/1005008543963830.html
It works reliably and can even power the fan directly via USB-C, which is useful when the battery capacity is insufficient.
Note: It charges with too much current for small batteries – I’m working on a better solution.
To reduce charging current and protect the battery, I currently use a 30 W USB-C power supply, which results in lower charging amps.
To save space during installation, I also removed the bottom capacitor from the board and soldered a larger capacitor externally to the wires.

Other parts

On/off switch

Potentiometer

3 × 1 mm magnet

M3 screws and M3 heat-set inserts

Power indicator module:
https://de.aliexpress.com/item/1005005727166588.html

Arduino Nano

Arduino Code (basic ESC control)

This is the current code. A version with RGB LED control will follow soon.

// Simple ESC control using potentiometer input
int esc = 2;
int poty = A7;
int escValue = 0;
int delayl = 2;
void setup() {
  pinMode(esc, OUTPUT);
}
void loop() {
  escValue = analogRead(poty) + 1000; // Read potentiometer value
  delayl = 3000 - escValue;           // Compute off-time for PWM
  digitalWrite(esc, HIGH);
  delayMicroseconds(escValue);
  digitalWrite(esc, LOW);
  delayMicroseconds(delayl);
}

Adapter Notes

I also designed adapters for inflating beach balls and air mattresses.
However, these are a bit tricky to use, because the inserted spike must press the valve from the correct side to allow airflow.

For the beach ball adapter, you additionally need to melt a small wire into the nozzle tip, like on the picture, using a soldering iron. This creates the internal spike required to open the valve.

I plan to design a simplified version of these adapters in the future to make them easier and more user-friendly.

Feedback

I’m very happy to see remixes or your own versions of this build – they help me improve my own design further.
Feel free to share your ideas or modifications in the comments.