The DC-DC Buck Step Down Converter problem

I use this module (CN3903 3A) to convert 12V to 5V to power two components: the esp32 and the 5V mini pump.

However, it is not capable of feeding both at the same time. After several tests, activating the pump causes the esp32 to crash.

But separately everything works.

Several solutions are possible: 

• Put two CN3903 one for the pump and one for the esp32 
• Take a 12V pump, allowing to power directly to the charger (but it is not a USB connector for the pump anymore)
• Use a 5V charger for the PCB and then use a boost converter to power the disks at 12V

For the moment I use solution 1 which allows me to test easily.

Disc nut optimisation

The old STL design, was too closed on the disk creating a water droplet retention preventing the creation of fog afterwards. The new design seems to solve the problem.

New PCB

I'm still testing the latest version of the PCB, the fog creation is good now I'm waiting to see if the disks don't get damaged over time.