I have been working on the wind turbine Wi-Fi repeater and communication node for several years now, and I am proud to say that the project is finalized. During 2009, the emphasis was making sure that the turbine would work reliably regardless of the weather that blew through Rochester. This was easier said than done, but by the end of the 2009 school year all aspects of the project were working correctly. In fact the turbine even charged an electric bicycle for the RIT Innovation Festival Green Vehicle challenge.
For 2010, the next phase of the project was to incorporate a power monitoring device and to improve the performance of the wind turbine. For the past year my friend David Brenner, and I have been working on an Arduino based power meter which would remotely measure the power the turbine was producing and then send the data through the Internet back to a server. Work progressed slowly since this was a side project for David and I, and we were both busy with school work and clubs. We eventually got everything working in the lab, but when we moved the power meter to the field we ran into a few software bugs. We needed to incorporate an auto reconnect function for the Arduino as occasionally the wireless link would stop working for a couple of seconds, closing the data connection. Additionally, the idle power readings would fluctuate slightly since the battery voltage would change over time. An improvement would be to use voltage regulators to power the circuitry instead of running it directly off the batteries. Luckily we came up with some software solutions and everything worked correctly. Once everything was up and running it was really cool to remotely see the power output of the wind turbine.
Earlier in the year, a bearing in the first motor died and I just replace the motor with a smaller Ametek 30v motor that I had lying around. The Ametek performed fine, but it didn’t produce as much power as the first motor. When spring came around and the wind died down, the batteries started to lose their charge. To fix this issue I upgraded to a much larger motor, which practically doubled the power output during windy days. Additionally, I added a 30W solar panel to help produce power during the summer when there is little wind in Rochester. The wind turbine and solar panel complement each other great in Rochester, as it is cloudy and windy in the winter while the summers are sunny with little wind. With the new motor and solar panel, the battery issue was totally resolved.
This past May, David and I entered the Wind and Solar Powered Communication Node into the annual RIT IEEE Design Contest. There were many impressive student projects and David and I were fortunate to win the award for “Most Innovative Project.” We were extremely pleased with the award, especially since we had devoted so much of our free time working on the project, most of it outside in the freezing cold. Sadly, a week after David and I won our award, RIT notified us that we would have to relocate the wind turbine as a parking lot was going to be built where the turbine stood. Since I was graduating and no longer would live in Rochester, I decided to dismantle the project and focus on some other priorities. While the wind turbine project is no longer standing at RIT, no all is lost. Dave and I documented all aspects of the project and created a great website: www.turbinehotspot.com which explains the project and contains numerous pictures and videos.
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.
The wind turbine has been relocated at RIT for the RIT Imagine Festival this weekend. I couldn’t have moved everything with the help of my two friends, Cody Racette and David Brenner. The wind powered communication network is working great! It is fun to see people’s reactions when an old fashion phone rings outside. The wind turbine is also powering an electric bike for the RIT Green Challenge. The wind turbine cabinet has a 12V cigarette connector which the bike connects to charge. The bike has a small 110v DC to AC inverter on board so a battery charger with intelligent logic can be used. So far everything is working great, and I expect the bike to perform well in the RIT Green Challenge.
The wind turbine was installed at RIT in early January. Since then, the turbine has only spent a total of two months setup producing power. The other two months it has either been awaiting parts or being repaired. Before this year, the turbine spent two six month periods in development testing without any issues. Why am I suddenly having all these issues? The answer is high winds. The turbine during development testing was in areas surrounded by trees sheltering the turbine from high winds. At RIT the turbine is on a hill, with a clear western exposure and the wind comes out of the west the majority of the time. This is great for performance, but I didn’t realize how much of a punishment it would put on the turbine.
Over the last four months I have had two tower failures resulting in the turbine crashing down. The first failure occurred when a storm with 40MPH winds blew through Rochester in mid January. This caused one of the 18” stakes which the guy wire attached, to be pulled out of the ground by the wind. To fix this issue I drove 6FT stakes 4FT into the ground which have yet to budge even in the strongest of winds. A couple of weeks later another storm rolled through, this time with 50MPH winds and the turbine yet again crashed into the ground. This time the wind tore out the eight, 4” screws which secured the base to the tower. This surprised me, since there should have only been a vertical force on the screws which would have been the weight of the tower and the turbine. I discovered that a horizontal force on the screws was the one responsible for the tower’s failure. I concluded that the top of the tower must have been staying because the nylon guy wires were not tight enough. The issue with nylon is that it stretches over time which results in the guy wires become loose and looser. To solve these tower issues, I bolted the wooden base to the tower instead of using screws. Additionally I replaced the nylon guy wires with steel cable which wouldn’t stretch. I used turnbuckles at the end of each guy wire which allows the guy wires to be easily tightened. The best part of the turnbuckles is that two people can lower the tower within a minute, whereas before one had to untie the nylon knots which was difficult in the sub freezing temperate of Rochester.
Two weeks ago, the strongest storm front of the year moved in. The winds were a constant 35MPH and gusted to 60MPH, which is approaching that of a tropical storm. To my delight the tower stayed standing, but the turbine had issues. The issue was that the blades and hub, fell off the turbine and were sitting at the base of the tower. What happened was that the two allen nuts on the arbor which hold the hub and blade to the generator’s shaft became loose. The wind pushed the arbor into the generator causing metal on metal contact. This resulted in the arbor machining through the metal around the motor’s shaft and caused metal shavings to enter the generator. The generator no longer spun smoothly and this along with the changing wind directions allowed the hub and blades to come off. To solve this issue, I lock tightened the arbor to the generator’s shaft, and any other parts that could become loose over time. I also cleaned rebuilt the generator and got it to spin smoothly again.
Overall, in the last four months I have learned a great deal about the project and made many improvements. The turbine and tower are now far more robust and should now be able to deal with the extreme winds that blow occasionally through Rochester.
For the past couple of months I have been spending a great deal of time on my wind turbine Wi-Fi network repeater. I have a VOIP adapter ready to be installed along with a phone, so one can make free calls from the turbine. It is like a portable self sufficient payphone and it doesn’t even require quarters! Cell phones have obsolete payphones, so why should I work on a portable payphone concept? Well, cell networks are not everywhere and they are extremely expensive to implement. In many developing countries an inexpensive and simple communication network would be easier to deploy at a fraction of the cost. Before I install the VOIP equipment, I need to repair the turbine. It has been an up and down battle with Mother Nature and 50+ MPH winds have exposed engineering problems with the project. More to follow soon!
