FAQ

Hardware

Q: Why use DC heating instead of AC?

DC is safer, simpler, and more effective for this application.

Q: Why does the main control board use different connector types instead of a single standard (for example, XH2.54 everywhere)?

This is intentional to prevent incorrect connections. Using different connector types helps avoid mis-plugging, which could otherwise damage the system.

Q: Why not use a capacitive touchscreen?

During development, only a resistive touchscreen was available. Since this project is provided free to the community, the author did not have additional budget to purchase capacitive touchscreens.

Q: Since ESP32 is used as the main controller, why not implement networking features?

ESP32 was chosen mainly because I already had a large number of spare ESP32 chips available. In addition, developing networking features requires a significant amount of time and effort. Due to limited personal resources, this functionality has not been implemented. It may be considered in the future if conditions permit.

Q: Why can’t 4-wire fans stop completely?

Some manufacturers implement a minimum speed threshold in the fan firmware for safety reasons. Even when the PWM signal is set to 0%, the fan may continue running at a very low but non-zero speed (typically around 200–300 RPM) to prevent overheating caused by a complete stop.

Q: Why do 2-wire fans sometimes fail to start at low speed settings?

Two-wire fans use DC voltage control. At low speed settings, the supplied voltage may fall below the fan’s startup voltage, preventing it from spinning. For this reason, 4-wire PWM fans are recommended.

Q: Heater plate temperature reads too high or too low?

Confirm the NTC wiring is secure and the sensor is fixed in the intended position. Large ambient temperature changes can also affect initial readings.

Q: Fans keep spinning after power-on?

Some fan firmware enforces a minimum speed threshold, so even with PWM at 0% the fan may continue spinning. This is normal.

Q: After enabling heating, the system reports an AHT10 / AHT20 sensor error, but the readings are normal when heating is not enabled. Why?

This may be caused by electromagnetic interference. When heating starts, the high current generates an electromagnetic field that interferes with the signal wires connected to the AHT20 module.

Try one of the following solutions:

1. Separate the wires connecting the AHT20 module from the wires connecting the heating plate as much as possible, keeping some distance between them.

2. Replace the two 5.1 kΩ resistors R2 and R3 on the main controller board with approximately 2 kΩ resistors.

3. Add a ferrite core to the two wires connected to the heating plate.

4. Split the GND wire of the AHT20 cable into two wires, and twist each one together with the SDA and SCL wires respectively.

Other

Q: Why is the software not open source?

The author does not want the software—developed with significant time and effort—to be mass-produced and sold commercially without contribution. While the author invests time in development, maintenance, and updates, resellers often profit without contributing and may shift after-sales support back to the author.