In the past month my friend David Brenner and I have made a great deal of progress with the wind turbine remote Arduino power meter.  The idea behind the project is to log the amount of power generated from the wind turbine and have the data automatically be uploaded online where it can graphed.  There are similar products on the market, but they are designed for much larger turbine and solar arrays, and thus are expensive.  We wanted to utilize the Arduino micro-controller as it versatile and inexpensive.  With all the parts the costs is around $80, which is a fraction of the cost of other solutions.

The power meter works by reading the current flowing from the turbine.  We are using a Hall Effect current sensor as it is very efficient and can handle up 30 Amps.  Based on the amount of current, the sensor outputs a voltage which can then be read by the Arduino’s analog to digital input.  An issue with the Arduino’s ADC is that it is limited to only 1024 values ranging from 0-5 volts.  This means that the Arduino is not very accurate and can only sense a 4.8mV change.  The issue we had was that the current sensor’s output voltage changes by a very small amount and the change couldn’t be read by the Arduino.  To correct this, we fed the current sensor into an amplifier stage to increase the output voltage so the Arduino could read smaller current changes.  The current sensor outputs 1.5v with no current, so to ensure that we weren’t amplifying the voltage when there was no current we needed to implement a 1.5v offset.

The Arduino microcontroller reads the data from the ADC input and then sends the data through the Internet to a server.  We are utilizing the wireless repeater portion of the wind turbine to transport the data through the Internet.  The server then reads the data and stores it in a mysql data base so graphs can be created.  The Arduino sends a new power reading every one second, so the graphs can be extremely accurate if we wish.  The remote power meter is currently in field trials to ensure the basic functionally works correctly.