Solar water heater pump

This is small but effective solar water heater pump. Its based on Arduino 328p, exactly I used Nano, and Mini Pro.

Versions:
2017
waterpump-sk3.zip is original from 2016, worked 1,5 years, recommended
2018
waterpump-sk4.1.zip advanced with menu OLED, worked about 2 months, deprecated
2019
waterpump-sk4.3 - slovak version
waterpump-en4.3 - english version

Other components are:
- 1x hose 1/2 inch for creating a spiral container for water heating.
- 1x flexible green garden hose 1/2 inch
- 1 input filter from foam
- 1 one way valve for feed water pump always with water
- 2A diode bridge for input energy for Arduino controller
- 1x DC/DC converter 24V to 5V DC for Arduino Nano
- 1x Arduino Nano, or Mini Pro 5V/16MHz with IC 328p
- 1x OLED 0.96 inch display I2C
- 1x PC817 optoisolator
- 1x IRF640N mosfet
- 1x 24 VDC brushless water pump, 800L/h, height 5m, 1/2 inch hose diameters input/output

- 1x thermosensor for measuring temperature k waterproof, sealed on outp