With the miniature circuit „Fancontroller 1x“ it’s easily possible to supervise a fan for its rotations. It’s checked whether the fan rotates or not while it is switched on. The voltage for the fan can be 5V-48V. 

Especially with all-metal hotends, it is very important that the fan cools the heatsink, the so-called „coldend“, well permanetly. In case that, based on a defect or e.g. material fatigure, the fan fails, the heatsink would get as hot as the heating block and would damage other parts of the printer.

The miniature circuit „Fancontroller 1x“ also monitores whether the plugged in fan is spinning while being switched on. In the event of an error, a sonic signal (bleep), a visual signal (a flashing LED) and a signal level (5V) will be occure.
Depending on demand, this signals can be used individually or alltogether to get informed about errors.
With the presence of a 5V-signal, a connected controllerboard with its printer firmware is usually capable to react appropriately for leading in measures for sue and labor.

Normal condition:
A fading LED (heartbeat) signalizes, that either the circuit is ready to supervise a fan or is already supervising a correctly functioning one.

In the event of an error:
When a fan is actuated but not rotating, a sonic signal will be released immediately and the LED starts flashing repeatandly. Additionally, the signal pin goes HIGH (5V).
The sonic signal can easily be deactivated manually with the help of a jumper. As soon as the fan is spinning again or is not actuated any more, the circuit will switch to it’s normal condition again.

The signal pin can be used for passing the error signal to the controllerboard and the firmware. The firmware can react applicable and depending on the configuration, e.g. pause or stop the print.

Additional properties:
- "voltage reversal" safe inputs
- Fan voltage 5V to 48V DC
- Supply voltage of the circuit is 5V DC (on 3.3V-ARM-Boards the supply is possible with e.g. the 5V servo-pins)
- Adjusting of the firmware, the sonic-, light- or data signal is very easy possible by changing parameters (Arduino IDE + atTiny85)
- Circuit, documentation and firmware are open-source (CC BY-NC-SA) (soon to comet, a DIY-kit will be available at )

Tags: E3D-V6, Youtube, Hotend