Advanced Member level 4
It is a design of electrical energy meter with three phases. The construction was inspired by:Openenergy with some modifications.
The microcontroller used in this design is Atmega328, software for which was made in Arduino environment. Internet website was made using php, ajax, mysql for standard browsers and smart-phones.
The energy meter reads:
- voltages L1, L2, L3
- currents L1, L2, L3
- calculated power L1, L2, L3
- temperature and humidity from sensor DHT11 (it can be changed to SHT due to the poor accuracy)
Voltage measurement is implemented on three transformers 230V/9V (gear).
Then, by means of a divider, the voltage is lowered until the safe value of Atmega328 pin.
The read accuracy can be calibrated by changing the value in firmware.
emon1.voltage(5, 211.9, 1.7); // input pin, calibration, phase_shift
emon2.voltage(4, 215.4, 1.7);
emon3.voltage(3, 215.4, 1.7);
Power measurement is made similarly to the voltage measurement, but using three current gears 20A – AC1020. It can be calibrated also in firmware.
emon1.current(2, 10.5); // input pin, calibration.
Results sending is implemented by transmitter 433MHz. Ready variables in the form of eg 230,231,231,1,200,1200,25,33. The first three variables are the voltage and the next three are the power, then temperature and finally the humidity.
There are also additional three diodes indicating the loss of power on the phase. Arduino 2560 is responsible for receiving variables. Arduino 2560 can be changed to Atmega328 which then connects to the www server. Script php is responsible for storing data in the mysql base.
List of elements:
- three transformers 230V/9V
- three AC1020
- transmitter 433MHz
- passive components
Link to original thread - Ethernetowy Miernik Energii Elektrycznej 3 fazowy