Today you’re going to learn how to build a simple and cheap low power wind turbine, fully homemade from scratch.
Want to know the best part?
A low power wind generator is a quite simple DIY project that can be entirely constructed using scrap parts. Today we are going to show you how to build two types of wind turbine:
- DIY Wind turbine from an old floppy disk drive
- DIY Wind turbine from an old VHS videotape
Does anyone remember what VHS tape or foppy disk actually is?
Table of Contents
- How To Build Wind Turbine using Floppy Drive Stepper Motor
- How to Build Wind Belt Generator for $5 using VHS tape
How does a wind turbine generate electricity?
Wind generator uses wind energy to generate mechanical power which is then converted into electrical energy. Check out this interesting animation of the wind turbine working principle.
How To Build Wind Turbine using Floppy Drive Stepper Motor
You can connect light bulbs, LED lights or similar devices that draw up to a few watts. The "heart" of our first home built wind generator is made out of parts scraped from an old 5.25" floppy drive!
Construction does look like a toy, but it can come handy in various situations: on camping, fishing, sailing or wherever the power grid is not available.
There was a good reason to use stepper motor salvaged from a floppy drive. PC technology is aging very quickly and floppy drive can be bought nowadays for a very low price. In most cases free of charge.
Stepper motors are very convenient for small wind generators. First, because they do not need any kind of gearing mechanism and the rotor can be attached directly to a turbine - propeller. This can simplify construction work and also lower the noise produced by the windmill.
Step motor produces stable voltage even on low rpm (200 rpm) which is a great advantage comparing to DC alternators/motors. DC motors require at least 10 to 15 times higher rpm in order to achieve similar power output. This is very important, especially during the low wind periods.
If you want to start with something even smaller, there is also a wind belt DIY project at the end of this post. Windbelt can charge mobile phones, Bluetooth speakers and batteries (AA/AAA Ni-Cd, Ni-Mh).
Do wind turbines produce AC or DC?
Most wind generators produce AC, however, there are some constructions that produce DC.
Step motor based wind turbine will always produce AC.
Do wind turbines need inverters?
Rectified and stable power supply is ensured using an electronic circuit (few diodes, resistor, condenser, and an integrated circuit). Anyone with previous soldering experience will be able to construct it.
EDIT: In 2019 there is no need to construct and solder electronic circuits. It is cheaper and easier to buy a complete circuit from aliexpress or ebay - 5-volt buck converters cost only several US$.
How much voltage does a wind turbine generate?
When it is windy outside, the generator of our small windmill produces electric energy sufficient for LED flashlight or for battery pack charging. Practical usage is virtually unlimited, we have attached USB female connector (with stabilized voltage 5.0 V) to our mini wind generator so that all modern mobile devices (iPad, cell phone, Bluetooth speakers, and more) can now be powered by the wind...
Do wind turbines require batteries?
The wind turbine does not necessarily need a battery to operate but you need to use generated power instantly. However, adding batteries to the wind generator system allows you to use electric power even during the periods without the wind.
Steps how to Build Floppy Drive Wind Turbine
First, find an old generation PC286, open it and remove 5.25-inch floppy drive unit - Picture 1. As you already guessed, the floppy drive will serve as a "donor" for the most important part - power generator stepper motor. After opening the floppy drive unit, carefully extract the stepper motor (pictures 2 and 3).
Drill two holes with a stationary drill on the shaft as shown in Figure 4. This we allow you to directly attach the turbine (propeller) onto the stepper rotor, using two screws.
Next, we will construct an electronic power stabilizer (Picture 5). This circuit will rectify alternate current (convert it from AC to DC) generated by the windmill and stabilize the voltage precisely at 5 volts (Picture 6) so that we can safely connect any USB device. Although we have used the printed circuit board, you can solder and interconnect all electronic components directly. You will need a soldering iron and some tin with solder paste.
Picture 7 - Wind generator schematic diagram
Electronic components should be soldered according to the electric diagram above. Wires coming out of stepper motor should be connected to rectifiers, in our case diodes 1N4004 (picture 7 - shown on the left side).
WARNING! Stepper motor usually has 5 wires coming out although you can find those who have 4, 6 or 8 wires. It is important to determine which type of stepper motor you have to be able to correctly connect the stepper with electronics of the wind generator. Here you can find necessary details how to connect different stepper motors. Although it`s not that easy to "burn" a stepper, caution is advised anyway!!!
We have bought USB extension cable (Picture 8) on e-bay, cut it in half and connected wires coming out of female USB connector directly to the output of windmill electronics (picture 7 - shown on the right side). The USB extension cable has 4 wires, but we only need the outer two, plus and minus 5V (Picture 9).
If you want to use a wind turbine for battery charging only, you can build much simpler electronics than the one we have used (Picture 10).
WARNING! Before connecting any USB device it is MANDATORY to check polarity and exact voltage (it has to be between 4.9 and 5.3 Volts) on USB connector using multimeter!!!
Now we need to make the remaining mechanical parts for the wind generator. We need to prepare a bracket and a turbine (propeller). The bracket can be made out of the aluminum tube with a diameter of 3-4mm. Do not forget to fix it firmly. If you plan to frequently move wind generator from one place to another, the easiest solution would be to fix the bracket using an umbrella stand to ensure mobility and stability at the same time (Picture 11).
Generator (stepper motor) can be easily fastened directly to the bracket using clamps or using a metal "L" profile. The solution actually depends on whether you will use horizontal or vertical turbine. We made both versions, it is up to you to decide which you prefer.
What is the best material for wind turbine blades?
If you pick a horizontal axis wind turbine, you can create a three-bladed propeller using the meter, pen, and scissors for cutting sheet metal.
You will need a sheet metal panel of 0.8x0.8m, 0.5mm thick. Cut out the pieces and form them as directed on picture 12, and attach the turbine to the rotor of the stepper motor with screws.
In case you do not have time to make everything by yourself, you can buy finished propeller very cheap (Picture 14) in any well-equipped hardware store.
For the vertical axis wind turbine, the simplest way is to make a turbine out of a plastic bucket (paint container). Cut it in the middle, fix it onto a round wooden or plastic plate (Picture 13). Finally, the whole windmill structure should be fixed on the generator rotor (stepper motor) with screws.
During strong winds (over 10 m/s), the mini windmill can produce 5 watts of electricity on average. This is a maximum you can achieve with floppy drive stepper motor, but output power also depends on the dimensions of the propeller blades.
Vertical axis wind turbine is most suitable for roof mounting because it is far more efficient in turbulent wind conditions (fast and often changing wind direction). For outdoor usage - you can use a windmill with the horizontal axis and three-bladed turbine.
Can a small wind turbine power a house?
Our small 5 Watt wind generator is not able to power a house, however, we are currently preparing another DIY project - a 100 watt Wind Turbine.
In combination with the right battery bank, 100 watts is enough power to supply a television set, LED light-bulb and a laptop. For a generator core we will use a stepper again, but this time from an old A3 dot-matrix printer.
Although the power of this wind generator is stil relatively small, it can easily power all LED lights in your home or serve as an autonomous power supply for the battery bank and mobile phone charging on camping.
The most important thing is that the successful construction of such a mini wind generator encourages you to subsequently make a much stronger wind generator which can reduce the consumption of non-renewable energy and decrease carbon footprint.
How to Build Wind Belt Generator for $5 using VHS tape
Micro wind belt generator is probably one of the cheapest and easiest DIY project ever. Even with its very limited power, a small wind turbine can be used in situations where conventional wind generator would normally fail to give any useful power output.
Windbelt is assembled using parts worth less than $5, which makes this windmill extremely cost effective! Price can go even lower in case you have an old VHS video tape, small fridge magnet, and transformer coils.
On camping or sailing, wind belt generator can easily top up your Bluetooth speakers, batteries, cell phone or a small LED flashlight...
What is actually a "Windbelt" Wind Turbine?
Wind belt is a vibrating membrane fitted with a pair of magnets that oscillates between copper wire coils. It works even in the light breeze which makes it ideal small-scale wind generator.
The device itself does not include any mechanical moving parts, it actually uses vibration to generate electricity. Conventional wind generators with rotating blades do not scale down so well due to high friction of moving parts and other mechanical components.
When it is windy outside, the small wind-belt generator produces power sufficient for solar LED flashlight or battery charging. Practical application is virtually limitless, we have attached a standard USB connector (with voltage stabilized @ 5Volts) onto wind generator and made it possible to connect all modern mobile devices (iPod, iPad, MP3 player, smart phone...) which usually charge via USB port.
VHS Wind belt Generator - Construction Details
First, we have gathered all the necessary parts for our micro wind generator. An old VHS videotape will be used as a membrane (Picture 1), two small neodymium magnets are taken from PC HDD (Picture 11) or from fridge-magnet souvenirs (Picture 2), and isolated copper wire coils - Picture 3. You need to fix the magnet(s) onto a VHS tape using glue. When a magnet moves near a coil, electrical current is generated and flows through the wire, therefore windbelt starts to generate electricity.
picture 1 picture 2 picture 3
Windbelt Inverter Electronics
If you want to use wind generator for LED lights or to charge batteries there is no need for some hi-tech or complicated electronic circuit at the output. In case you want to charge batteries only, you can use a very simple rectifier circuit (Picture 4).
If you want to charge USB powered devices then you also need a small voltage regulator in addition to rectifier circuit (Pictures 5, 6 and 7), two neodymium magnets and two coils (connected in series) on the windbelt.
Electronic components should be soldered according to schematic diagrams shown below. Wires coming out of the coil(s) should be connected to rectifier diodes (Picture 7).
picture 4 picture 5 picture 6
WARNING! Diodes can be connected correctly only one way! Check out how to determine the polarity of a diode, it is important to locate the anode pin. Low power 1N5817 Schottky diodes are most convenient for windbelt generator.
picture 7 - Windbelt electric schematic diagram picture 8 picture 9
We have bought USB extension cable (Picture 8) on e-bay, cut it in half and connected wires coming out of female USB connector directly to the output of windmill electronics (picture 7 - shown on the right side). The USB extension cable has 4 wires, but we need only outer two, plus and minus 5V (Picture 9).
WARNING! Before connecting any USB device it is MANDATORY to check polarity and exact voltage (it has to be between 4.9 and 5.2 Volts) on micro-wind-generator USB connector using volt-meter!!!
Windbelt Power Generation Principle
The prototype with a 65cm long membrane (Picture 10) and strong neodymium magnet (Picture 11) can generate 40mW in a 10mph wind.
Not a lot of power, however, an array of wind belts could be assembled to generate as much power as it is required, and easy to maintain. Existing Windbelt prototype can generate electricity in winds over 4mph and at attack angles of up to 60 degrees.
What wind speed is needed for a wind turbine?
As the wind speed increases from 4 to 14 mph, the power output increases at a rate close to a cube of the increase in wind speed. At wind speed above 14 mph, the power output becomes constant.
One way to improve and stabilize the output of a wind belt turbine across a wider range of wind speed would be to dynamically increase the tension of the membrane as the wind speed increases...
picture 10 picture 11
The key advantages of windbelt over existing micro wind turbine technology are not only the cost but simplicity. Also, the fact that it is good at taking power from turbulent wind flows, i.e. in a built up domestic setting, and it is also very quiet in operation.
Unlike PV solar panels, wind turbine generators do not scale down so well. While large wind turbines can generate huge quantities of electricity very efficiently and relatively cheaply, as the size of the wind turbine is reduced, efficiency reduces and costs per generated watt jumps quite enormously.
Wind Belt Turbine Usability
Wind belt is an ultra-efficient and mechanically very simple wind generator alternative. Its cheap components can be bought almost anywhere in the world. Windbelt is originally an innovation of Mr. Shawn Frayne.
He constructed this simple device with a taut Mylar membrane fitted with a pair of Neodymium magnets that oscillate in and out of coils because of the mechanical resonance of the membrane with the wind blowing across it.
At wind speeds of 10 mph, the membrane oscillates at 90-100hz - i.e. the magnets move in and out of the coils 90-100 times per second. Unlike a photovoltaic solar panel or conventional wind turbine generator, Wind-belt can be constructed, repaired and maintained by just about anybody.
Larger homemade versions of the wind belt are possible, but usually, the problem of noise emerges. In any case, we have to be aware that the power potential of this kind of low-tech energy source is quite modest. That is why they can be used only to supply power to devices with very low energy consumption or to be used in remote areas where we do not have an alternative.