Storm in teacup (acetone bath)

thingiverse

Materials: - 4L sealed box made from polypropylene - HDD motor from old 3.5" 250GB Western Digital drive - Model aircraft Electronic Speed Controller for brushless motors, you may use almost any model, I used Turnigy 20A - 12V Power Supply Unit, 10W is enough (1A) - Servo tester, I made one from ESP simply because I didn't find a potentiometer in my components box Motor plate designed in FreeCAD. Impeller is a modified version of [Centrifugal impeller](https://www.thingiverse.com/thing:259773), unfortunately I lost the source file, but modifications are easy - holes to tightly fit on motor outer diameter. To assemble, you need cut a hole for the motor and drill 4+3 holes for M3 screws, then apply silicone sealant and tighten screws. Then check the impeller, I used a disc spacer ring to mount without disbalance. Then solder ESC wires to the motor, there should be 3-phases and (possible) central output, use an ohmmeter to find phases (mine have 4 Ohm phase-phase, 2 Ohm phase-center). Check rotation direction, if it's wrong you may change ESC settings (if it supports) or swap any 2 phases. When all tested to be working I sealed wires with ABS juice (plastic in acetone) and glued the impeller with thread lock. ESP8266 is not required, just I don't have a free servo tester, so I made one with MQTT control :). It connects to an MQTT broker (mosquitto), then using [MQTT Dash](https://play.google.com/store/apps/details?id=net.routix.mqttdash) I may control PWM value. "Smart" vapor bath :). Benefits from HDD motor - it is sealed (use less acetone, no losses via motor hole), and it is **very quiet**! Also I use a spear stand for a while, it is useful, but require strong metal backplate. Place a piece of cloth at the bottom, it helps to evaporate faster.