As the tubing did finally arrive, I absolutely had to do a first quick test. I connected some tubing to one of the pumps using hot glue. Additionally, I glued a magnet to the tubing with which I want to position it on the inner wall using a second magnet from the outside. Then I attached the pump to the 3.3 V of an ESP8266 using a breadboard. While powering the ESP8266 over USB the pump was active, but the pressure inside the tube was not strong enough to actually blow bubbles under water. In fear of the voltage being too low, I connected the pump to the 5 V of a Raspberry Pi. However, still no bubbles. Also, the magnet got loose.
- As I could see some air being displaced, the pump itself should be powerful enough. But as A_1*v_1=A_2*v_2, I should decrease the diameter. The tube (8 mm inner diameter) is too wide -> order thinner one
- Hot glue does not stick to anything well -> attach differently, maybe “Kabelschelle”?