Arduino based remote monitoring of temperature and heater pump status over (the cheapest) wireless 433MHz link. Transmitter uses 5v input voltage to detect if pump is running (phone charger method), and KTY81 temperature sensor for the heater temperature. Receiver displays the temperature on a two-digit segment display, and pump status by turning on an LED indicator.
I am proud to say that the system is running flawlessly since April 2017 in my house.
Coming soon!