After a period of operational evaluation and design refinement a smaller and more efficient Solar Pump Regulator has been developed. This device acts rather like an intelligent solid state relay to protect the well being of the pump, pressure switch and battery whilst making good use of harvested solar power. This device does not have much to do with Raspberry Pi except that a Raspberry Pi was used for development of the operating program (Arduino sketch) used by the ATtiny 45/85 microcontroller (MCU). A Raspberry Pi continues to be my preferred device for programming MCUs prior to assembly and deployment of Solar Pump Regulator units.
Comprehensive design documentation has been released into the public domain (click here) so that anybody can produce Solar Pump Regulator devices in accordance with the present design or derive modified versions as they see fit.
Although the design is optimised for the intended application as a Solar Pump Regulator, the device is essentially a power MOSFET switch controlled by a programmable MCU which can measure the voltage of its battery supply. Consequently there are other possible applications that could be addressed by substitution of an appropriate Arduino sketch designed to match the intended application.
A photo album has been created (click here) and more photos will be added in the coming weeks.