Introduction: AC Monitor System Using Intel Edison (Intel IoT RoadShow Brazil)

A system that check voltage, current, frequency and temperature of an AC power system, calculate total power consumption and post all info on a cloud data server.

Step 1: AC Sensor Module

We developed this sensor module based on the project Open Energy Monitor .

This module allow us to collect measurements on a three-phase AC electrical system, providing voltage and current of each phase + AC frequency and temperature. The firmware was written in C/C++ and merge all data in a payload of 32 bytes. The payload is send wirelessly to intel Edison using an ZIGBee protocol (Xbee modules).

For current sensing we use Current Transformers SCT-013 of 25 Amp and for voltage sensing we use simple transformers that reduce 220 volts to 9 volts AC.

The AC sensor module receive voltages from CTs and transformers, put this voltages in levels accepted by micro controller ATMEGA and the firmware calculate voltages and currents. This module also have a zero cross detector that generate a interruptions to ATMEGA allowing this to calculate the frequency of AC power.

All data received and calculated by the AC sensor is send wirelessly to Intel Edson via ZigBee protocol using XBee modules.

Step 2: The Brain

The brain of the system is an Intel Edison, a XBee shield and an OLED display.

The code was written in C/C++ using Arduino IDE and it has the function of receive 32 bytes payload from AC sensor module, calculates de Total Power consumption and put all information collected/calculated in the OLED display, all data is also published in a data server on the web. The complete code runing on Edison is attached .

Step 3: Aditional Hardware Connected to Edison

We use an "IO Expansion Shield for Arduino V7.1" from DFRobot and a I2C 128x64 OLED display from SeeedStudio . This modules adds XBee connectivity and display capability to Intel Edison.

Step 4: Wireless Comunication

The wireless communication between AC sensor module and Intel Edison is done using ZIGBee protocol.

We use Serie 1 Xbee modules from DIGI operating in API mode 2.

Step 5: Data Publishing

All information collected is published in a data server from SparkFun and can be viewed using the following link:

IoT RoadShow AC monitor project