Accuracy of measurement: (8 readings per second and averages )
Ultrasonic ranging module HC - SR04 provides 20 mm – 5000 mm non-contact measurement facility, the ranging accuracy is 3 mm and aperture angle is 15 Degree.
Component list & price:
- ATMEGA328 based Arduino pro mini – 2 nos: $4
- HC-SR04 Ultrasonic probe – 1 no: $1
- LCD Hitachi – 2*16 char – 1 no: $2.8
- 433 MHz Tx & Rx – 1 set with antenna : $2 to $4
- 5 volt 2 ampere power supply unit – 2 set: $8 to $10
All the above price list are based on aliexpress.com.
Principles of operation:
It checks the code word first and then displays the level. If the remote Tx fails it indicates on the remote unit. The free GPIOs can be used for running the relays / contactors for running / stopping pumps.
Check for connections and voltage level at various stages.