These pages will help you better understand the major systems when constructing a solar structure or wind turbine. There is a lot of information here so take your time and explore all the links and information!
To succeed at a KidWind Challenge it is very helpful to measure the power output from your wind turbine and solar panels. It is also very handy to be able to measure the power consumption of various loads you may attach to these devices. You can use a simple multimeter or data logging equipment to collect this data.
While we love the cost and ease of a simple multimeter, we really love Vernier’s Go Direct Energy Sensor (GDX-NRG). It connects to all devices and is an easy way to collect detailed turbine and solar panel electricity data. The great thing about this device is it allows you to collect voltage, current, power, energy and resistance simultaneously and compare the data over different trials. It also has a built-in 30 ohm test load so you can put your solar panels or wind turbines under load.
It is pretty amazing. We recommend classes have at least one Go Direct Energy Sensor and then 4-5 multimeters.
For the wind portion of a KidWind Challenge a large component of your score is turbine performance. We will put your turbine in a wind tunnel and see how much energy it generates over a period of time. The Go Direct Energy Simulator simulates this experience in your classroom but if you do not have one you can use our performance calculator which will help you approximate the power output and energy production of your turbine. All you need is a basic multimeter and some resistors.
In the solar portion of the KidWind Challenge we ask quite a few questions about how much load your solar structure can power and the current and power consumption of various loads in your device. Knowing how sensors and multimeters work can make this much easier.
For the wind and solar competitions we have a maximum voltage and current limit that is important to stay below for safety reasons and so you do not get disqualified!
There are many different plans and designs for wind turbines, but they all share a few things in common. No matter what kind of model turbine you build, it will require some of the same parts as a real wind turbine. You need a tower, a generator, a rotor, and of course wind!
You will need to set up a model wind turbine and a fan. You will also need some kind of meter to measure the power output of your data, unless you are using your turbine to do non-electrical work such as weight lifting. Check out the measuring electricity page for details.
Here are some materials besides a turbine and fan that you may want for the experiment:
Tape: For marking a consistent spot to place the turbine
Multimeter: Or some kind of meter or load device that will measure the amount of electricity your turbine produces.
Wind Speed Meter: If you want to see how wind speed affects power output, you should use an anemometer to measure the wind speed of your fan.
Fans: You should use a floor fan that has at least 3 settings so you can experiment with how wind speed affects power output. We recommend a fan that has a diameter of at least 20 inches and that can be propped to the height of your turbine. Lasko fans are usually good.
The generator your team uses determines how we classify and evaluate your turbine in the wind tunnel and compare energy and power generation from different turbines.
In addition to the age level divisions, there are three technical divisions in the wind portion of the KidWind Challenge — the KIDWIND division, the OPEN DIVISION, and the HOMEBUILT division.
In this division there is one generator that is allowed and each turbine can only use one in their turbine!
We find that the easiest path to start building and testing a KidWind Challenge wind turbine is to get a few KidWind Wind Turbine Generator (KW-GEN) and some hubs from Vernier. The KW-GEN is a simple DC motor/generator that was selected because it spins smoothly, produces measurable voltage at low RPM, and is affordable. The power output on this generator peaks out around 3 watts before it fails due to heat and max RPM.
Build yourself the "Basic PVC Wind Turbine" (the first turbine we ever invented) and you are off and running.
At some point you may build turbines that burn out the KW-GEN or you want to explore in more depth how generators work or you just want to generate more power! The OPEN DIVISION was designed for wind geeks like this. You can purchase a commercially sold AC or DC generator (not a KidWind generator) that better matches how much power your turbine can generate.
For those really looking for a challenge, you can construct your own generator using a kit, online plans, or your own ingenuity. A home built generator is defined as a generator where ALL of the major components of the generator are constructed by the students. This would mean the coils are wound by the students, the stators and other components have been constructed, 3D printed or otherwise built by the team. This does not extend to the magnets or driveshafts and similar components in this device.
You can also find many more resources and kits online about building your own generator. For the really studious, check out Homebrew Wind Power by Dan Bartmann and Dan Fink and construct your own generator and turbine from scratch!
A Note on Advanced Generators
The key to using a homebuilt or commercially available generator is to make sure the power output does not exceed 30V at 1A at any point in testing. You will also have to properly match a load to your generator for maximum efficiency. This can get complicated so you should read the rules and do some homework!
Wind turbine blades and their orientation to the wind are very important parts of the turbine design. You could study this for years and still not be an expert! The only rule we have about blades is you cannot use pre-made airfoils and your blades should be made of safe materials. We see students using all kinds of materials to make blades: cardboard, balsa wood, 3D printers you name it. Just don’t use razor blades!
Gearboxes or Belt Drives
While building a gearbox or a belt drive can be challenging, it can also greatly increase the power output of your wind turbine. Belt drives or gears can give your wind turbine a mechanical advantage and multiply the mechanical force of the turning blades.
Your team can use KidWind gearboxes and parts through our partners at Vernier, you can find parts from other vendors, or you can construct your own gearboxes or belt drives. The only rule is that we must approve it as safe!
You can make a tower for your wind turbine out of practically anything. We have seen some great towers made from wood, cardboard tubes, Tinker-Toys, plastic, etc. Try experimenting with different designs!
The only rule for making your tower is that it must have a firm base to sit securely on the ground, and it must be tall enough so that your blades will not hit the ground or the top of the wind tunnel. If your turbine has a gear or pulley system, you will need to have some kind of platform or housing on top of your tower to hold the gear/pulley box.
Fans and Wind Tunnels
You can use any fan to test your turbine! We use simple box fans for most of our classroom work. It is important to have a test area with a multimeter or sensor connected so you can quickly test any changes to your turbine to see if things have improved.
You should use a fan that has at least 3 settings so you can experiment with how wind speed affects power output. We recommend a fan that has a diameter of at least 20 inches and that can be propped to the height of your turbine.
At KidWind Challenge events, we will have a KidWind Competition Wind Tunnel (KW-TUN) or something very similar to test your turbine. The KidWind Competition Wind Tunnel is easily constructed and can be purchased from our partners at Vernier. Unlike a box fan, our tunnels suck the air through the shroud which leads to cleaner less turbulent winds.
If you are handy with tools and a ruler, you can try to construct your own – many teachers have done this! One of our amazing REcharge Instructors, Dick Anderson, has posted a number of plans for building your own wind tunnel. For different fans, use our Fan Speed Cheat Sheet.
It can also be helpful to have an anemometer to measure the wind speed of your fan at various speeds. Wind speed data can help you do a deeper analysis of turbine efficiency.
While the wind portion of the KidWind Challenge is primarily focused on building the most powerful turbine you can, the solar structure challenge is focused on creativity and how well your team can learn and apply your knowledge around electrical circuits, solar panels, and loads.
Size and Materials
Your solar structure and all accessories must fit in a 1-meter cube. Having a bigger structure will not boost your score. You will want to make sure you leave some space (maybe 10 to 20 cm) around the edges of your structure.
You can use anything to construct your invention. We are especially fond of repurposing found items like old dollhouses, model cars, and recycled materials. Remember that resourceful and responsible use of materials is considered during the judging process.
You can use solar panels from any company and you can use any number of solar panels. The 2V panels from Vernier are very sturdy and in arrays can power many different loads.
As we mentioned before it is not about how large or how much power your solar structure can generate, but the creativity and execution of your design that is important.
Teams can only use solar panels that are 6V or below and produce less than 1.1A - this is a common size used by the Junior Solar Sprint Competition. If you combine solar panels in a parallel or series configuration, please make sure that your array is not producing more than 12V at 2.2 amps.
If you are not sure how combining solar panels affects voltage and current, it is time to do some research and testing. A solar panel is basically a DC power source. If you combine panels in series, you will increase the voltage they can provide. If you combine them in parallel, you increase the available current they can provide.
Loads and Storage
You can use any other loads to make your structure or design interesting. These can include LEDs, incandescent bulbs, motors, capacitors. These do not have to be new items; you can dissect and scrounge things from all sorts of devices. We love cutting up old holiday bulb strings and finding parts in old electronic devices. The key question to ask yourself when using items that you find is: can they be powered by the solar panels that you are using?
Pre-manufactured circuits or circuitry kits are allowed (little bits, snap circuits, etc), but will be noted in the judging process.
As a part of the judging and reporting process we ask all teams to provide a wiring diagram. This will help us understand what you were trying to do with your solar structure. These do not have to be formal wiring diagrams (but they can be), but they should details all the electrical parts of your solar structure such as solar panels, loads, switches etc.
If you want to integrate a microcontroller into your solar structure (or wind project for that matter) we think that is awesome. Microcontrollers are a small computer that you could program to make things happen in your solar structure - such as, turn a light when it gets dark or make an elevator go up and down when you press a button. Some examples of microcontrollers include Makey-Makey, the microbit, Hummingbird Robotics, Arduinos, and the lilypad.
The microcontroller can be externally powered using a battery or plug or for super serious bonus points, it can be powered by the sun as well. NOTE: This could be very difficult!