The idea to create this bicycle generator was born at the moment when the battery charge was completely depleted. If you want a light on your bike to brightly illuminate your path, but don't want to have the hassle of recharging or buying batteries, this material is for you! 
Brief description of the project:
- No batteries! The energy will be accumulated in two supercapacitors with a capacity of 100F and an operating voltage of 2.7V.
- Charging will take a few minutes, but the light will shine at its brightest as soon as you start pedaling.
- Before the light starts to go out, at least 15 minutes must pass from the moment of stopping (for example, when stopping at a traffic light or in another situation when the generator is not working). A powerful 1W LED has an operating voltage of 3.5V. Taking this into account and using the right resistors, you can change this time period from 4 to 30 minutes. LEDs consume current up to 350mA, the design in the example is powered by 350mA current and the light remains bright enough to blind drivers.
- The generator provides lighting and at the same time stores charge in the capacitors. In the example, a stepper motor from a dot matrix printer was used. Using a multimeter, it was determined that it can produce a current of up to 500mA.
- Another advantage is that the capacitors are self-regulating. This means they won't be overloaded while charging.
First of all, to assemble a bicycle generator you must find a stepper motor suitable for our purposes. You want a motor with very low resistance in the coils. The example uses a motor whose label indicates 2.88V and 2.4A, with a coil resistance of 1.2Ohm. During testing, this motor produced a current of 500 mA at 400 rpm. When riding a bicycle at a speed of 15 km/h, the generator will make from 160 to 200 revolutions per minute. This means the motor needs to be mounted close to the rear wheel hub to reduce the effort required to turn it, unlike the old 1000 rpm dynamo.
Secondly, you will need to purchase a pair of supercapacitors discussed above.
Thirdly, you will also need:
- Imported diodes 1N4004 (8 pcs) - they convert the alternating current generated by the engine into direct current.
- Voltage stabilizer LM317T (1 piece).
- Ceramic capacitor 0.1 µF (1 piece).
- Resistors 240Ohm and 820Ohm 0.25W for the voltage stabilizer, which will give us the 5.5V current needed for the capacitors. This value must not be exceeded!
- 1W LED (1 piece).
- A resistor for an 11Ohm 0.25W LED (1 piece), will give a current of about 160mA.
Here is a list of what you will also need:
- Headlight housing in order to insert the LED there.
- Small housing to protect capacitors from damage.
- Wires.
- A piece of plastic pipe with a diameter of 10 cm and a width of about 2.5 cm. It will be secured with epoxy resin to the spokes of the wheel.
- Rubber pulley or wheel for the engine with a diameter of 5 cm.
- Various tools, including a soldering iron.
Let's start assembling our bicycle generator. 
Firstly, I didn't bother creating a PCB, but simply soldered all the circuit components together, and then filled everything with epoxy glue to protect it.
The motor in the example has six wires, two of which will not be used (Com), and the other four, from the windings, are the ones that we will need.
By soldering the diodes in this way, as shown in the diagram, we get a parallel circuit of two diode bridges, which converts alternating current to direct current. Solder a capacitor between the plus and minus, this will stabilize the voltage regulator. After this, solder the LM317 and resistors in place. Install the LED and current limiting resistor in the headlight housing. Connect the wires to the headlight with the capacitors, including a switch in the circuit between them, and then to the voltage stabilizer.
Connection sequence:
Stepper motor - Voltage stabilizer - Capacitors - Switch - Headlight
Now let's start installing the engine on the bike. To secure the motor, use pipe clamps that can be secured in the holes for disc brakes. The rubber motor wheel should run over the surface of a section of plastic pipe with a diameter of 10 cm. This section should be secured using epoxy glue and adhesive tape, but may need threaded clamps to secure it more securely - this will prevent the rubber wheel of the bicycle generator from slipping on its surface.
A bicycle generator is a device that allows you to generate electricity by rotating the pedals and transfer it to the bicycle’s lighting fixtures or third-party electrical appliances. By design, bicycle generators are divided into several types: bushing, bottle, carriage and contactless.
The current and voltage output are inextricably linked to the pedaling frequency - the speed of movement. The pattern is valid for all types of generators. The bicycle generator produces alternating current, which is stabilized into direct current using a bridge rectifier. Its role can be played by soldered diode lamps or special devices, for example, a full-wave rectifier.
A hub dynamo, or bushing generator, is a regular one with a built-in magnetic mechanism. During rotation, eddy currents are formed; at the exit from the bushing, mechanical energy is converted into a current with a given force, voltage and power. On bicycle dynamos, the voltage reaches 6V and the power is 1.8-2 W.
The invention was patented by the English company Sturmey Archer. Nowadays, production is actively supported by other manufacturing companies - Shimano and Schmidt.
Features of the generator bushing design:
Dynamic Shimano AlfineDH-S701
The bushing source of electricity does not use the bicycle frame as a ground and, together with the lamps, is isolated from it. In a full-wave rectifier, the AC circuit (output) and DC circuit (to the headlight) are completely separated from each other.
Hub dynamos are heavy, although lighter rare-earth magnets and an aluminum shell have made it possible to slightly reduce their weight. In operation, the device has low resistance to unwinding, and as the angular velocity increases, the frequency of the current increases. This effect smoothes out the voltage gain and allows the generator to operate over wide speed ranges.
The headlights that the bushing generator is equipped with have a built-in current stabilizer. When connecting another headlight, a separate rectifier is installed in the circuit so as not to burn the electrical appliance. The brightness of the headlight depends on its requirements for the energy source and, in fact, the output voltage of the bushing. The greater the discrepancy downward (the headlight is more powerful), the dimmer the light will be. In the opposite situation, the light source will not work.
Let's get acquainted with another energy source - a bottle, or “bus” converter.
A bottle electric generator is a closed housing with a rotating rubber roller on the outside, attached to the front fork. The housing contains the direct converting device – winding and magnets. The movement of the magnetic field is achieved by engaging the roller with the tire and directly transferring mechanical energy from the wheel to it. The higher the speed, the stronger the polarity inside the generator and the greater the voltage output.
"Bottle" is afraid of bicycle falls
Advantages of "bottles":
Weaknesses include:
Separately, it is worth mentioning the carriage bicycle generator. Its body is fixed in the area of the pedal assembly - the carriage, under the lower stays. The rotation of the magnetic device is set by a roller that is engaged with the rear wheel of the bike. The roller is secured to the tire by a clamping spring.
The bottle and carriage generators produce electricity when they come into contact with the moving wheel. The hub dynamo is a built-in element of the wheel. The contactless generator does not touch the wheel in any way and does not create friction forces or resistance to rotation. Eddy currents are formed due to the close proximity of the plane of rotation of the magnetized rim and a strong magnet.
The headlights are built directly into the device, electricity is transmitted directly through the rectifier bridge. The undeniable advantages of this generator include:
Non-contact energy sources can be safely used on road bikes for long journeys
The devices are attached in pairs: on the fork - the headlight, on the feather - the rear reflector. In fact, these are independent flashlights, only they do not work from batteries, but through the rotation of wheels in a magnetic field. The luminosity of the lamps is at the same level as or exceeds that of battery-powered lighting devices.
As the wheel slows down, the intensity of the eddy currents decreases, the lights should dim, and when the wheel stops, they should go out completely. To ensure uniform light and the ability to use the light even when parked, the design includes a capacitor (“battery” for generating electricity), which is filled when the bike moves.
Now let’s try to make a generator for a bicycle ourselves. We will use a stepper motor as a basis. To power the lighting devices you will need a motor with the following characteristics:
The dynamo should be installed near the rear wheel hub. To transfer rotation from the wheel to the flywheel (rubberized wheel) of the motor, a transfer ring is needed. To create it you will need flexible plastic tape. Manufacturing:
When the ring is ready, a stepper motor is screwed onto the free seats on the feathers, and the flywheel is installed on top of the ring. If there is no free space for the engine, you will need to weld an additional plate with holes onto the frame.
General diagram of creating a generator with your own hands: generator - assembly of the electrical circuit (bridges, resistors, capacitors) - connection - installation of headlights.
To assemble the electrical unit for the headlights you will need:
We assemble the components taking into account the following diagram:
Another version of this scheme:
Assembly sequence:
Homemade electric generator for the rear wheel of a bicycle
The housing with the electrical circuit is fixed on the bicycle frame, the wires are secured with clamps.
At the last stage, the operation of the system is checked: the wheel must move freely along the wheel and move synchronously with it. With a correctly assembled electrical circuit of capacitors, resistors and rectifier bridges, the headlight will turn on. True, at low wheel speeds its light will flicker.
An electric generator will allow you to extract additional benefits from pedaling - receiving absolutely “free” energy to illuminate your two-wheeled vehicle when driving along a dark highway or rough terrain. Small and useful, this device requires virtually no maintenance and can easily be assembled yourself.
Hello, dear comrades! I bring to your attention an environmentally friendly source of electricity.
Due to the nature of my work, I have repeatedly had to solve problems of energy supply to remote objects. However, the methods used are not acceptable to me for financial reasons. What remains is experience.
When planning the backup power supply for my “facility”, I proceeded from the technical and financial possibilities available to me: when the electricity runs out in one feeder, I switch to another (ATS), the entire external network will shut down - there is a gasoline generator, the fuel will run out (well, or to save it) - solar panels. As a reserve - 6 pieces of assorted batteries from cars (“certified” capacity from 44 to 115 A*h). Their capacity, of course, is not the same as in their youth, but for small loads they are quite suitable (I also use it as a starting battery for resuscitation of frozen cars).
The minimum total power of consumers in winter is 100 W (boiler automation, circulation pump and 2-3 LED lamps). In the event of an acute shortage of gasoline, I will not be able to provide so much with the grace of the sun alone (short winter day + snow). Well, or you need to increase the area of solar panels (a rather expensive pleasure).
The idea of creating a simple backup source of electricity “from what is at hand” has been around for a long time. I don’t think it’s wise to invest a lot of money, by my standards, into something that may never be needed.
So we have: used car batteries in an assortment, a used 80A generator (from dozens of VAZs, changed at the time for a more powerful one), my son’s bicycle. And legs. Well, and of course, hands. 
My son made a stand for the rear wheel from pieces of plywood. The rear wheel axle nuts were replaced with “pegs” (foot supports, used when performing cycling stunts). Using pieces of metal profile and M8 studs, we secured the generator to the rear wheel. We connected the battery and started charging it. 
Yeah! Right now! There is not enough strength. I started to figure it out and count. The relay-regulator keeps (it tries) 14.5 V, the battery charging current is 4-5A. Total more than 70 W. Taking into account the losses of the pedal-chain-tire-pulley, you probably need the same amount more. Vicky reports that this is unrealistic - I have never been an athlete.
We need to somehow reduce the power. The charging current depends on the design (size) of the battery, you can’t change anything here - we use what we have. The tension remains. I remember that motorcycles had 6 volts. You can remove 6 volts from a 12-volt generator by using a suitable voltage relay instead of a standard car one. And charge a 12-volt battery in two passes, “dividing” it in half. This will halve the effort on the pedals by doubling the time they rotate.
In the battery I used, the jumper between the third and fourth banks is located just under the plug (if you remember before, the jumpers were on the outside, now I’ve only seen them on trucks). I found a 100-mm self-tapping screw, stained with silicone (I cleaned the nose of the gun). Silicone protects the iron self-tapping screw from acid, or rather, on the contrary, electrolyte from foreign iron. Slowly, carefully, with force, I screwed it into the jumper (the main thing here is not to overdo it and not to twist it all the way through - you can short the plates in this jar) and got the third contact. We must remember that it is positive if it is paired with a standard “minus” and negative if it is paired with a native “plus”. 
I converted the standard relay-regulator into a simple brush assembly (I bit off the relay legs, soldered the wires), installed PP1 from IZHAK and the process began! The motorcycle relay kept the voltage no higher than 7.5 V (average approx. 7 V), average charge current approx. 4 A. The effort on the pedals is normal, for my untrained body. In general, everything works.
However, as we were taught in ML philosophy classes: practice is the criterion of truth! It is necessary to evaluate the practical value of this energy source. The following assessment methodology was proposed: the control battery is connected to the emergency lighting until the latter goes out. After this, the battery is charged using a pedal for one hour and reconnected to the lighting. The ratio of charging time to lighting operating time can be a parameter for assessing the efficiency of the system. 
Emergency lighting system - LED strips (left over from apartment renovation) with a total length of 5.7 m, glued to the crane beam guide. Operating voltage from 12.5 V to 8 V (average 10 V), current 0.8 A. Average power consumption 8 W. If we assume that from the generated power of 28 W (7 V * 4 A) we can “store” 20 W, the expected operating time of the emergency lighting system is approx. 2.5 hours.
The previously discharged battery (to 7.5 V under load with an LED strip) was charged for 40 minutes. My son and I took turns pedaling for 5 minutes - it turned out to be not an easy task. 20 minutes for one half of the battery and 20 minutes for the other. 
Then they connected the emergency lighting to it and began to wait. Here I was met with bitter disappointment - my calculations turned out to be wrong. After two and a half hours we went home, leaving the LEDs on. In the morning, 12 hours later, I went to check - they were glowing, they were infected. After another 8 hours there was almost no light - the voltage under load dropped to 7.5 V.
In general, after 40 minutes of recharging with the bike generator, the operating time was about 20 hours. I made a mistake somewhere But the main thing is that the result was achieved. Having such a device, you can provide yourself with electricity sufficient for modest lighting and operation of not very powerful devices. An hour on an exercise bike – a day with light
Practical advice for those wishing to repeat the experience:
A bike with gear shifting is highly desirable - you'll start at one speed and finish at another.
Swap the tires on the wheels. The rear tire has a developed tread on which the generator pulley bounces, constantly bounces and loses drive.
Do not use a semiconductor relay-regulator - the field winding of a car generator is designed for higher power than the output stage of a motorcycle relay. This is how I burned the relay from Java. 
It is necessary to monitor the charging process using a voltmeter (for example, at least 6.5-7 V), an ammeter (± current) or a control light (some relays allow you to install it).
If you stop to rest, remove the terminal from the battery; the discharge through the relay with the generator will quickly consume your work.
Although there are records. During one of the tests, it was possible to generate 12 kWh in 24 hours. But this is not the limit; Siemens stated that it had created an installation with the help of which a person was able to obtain 4.2 kW/h in an hour. But 62-year-old inventor Manoj Bhargava assembled a unique exercise bike. Using it for just one hour can provide electricity to a small house for a whole day. The scientist hopes that Free Electric (as he called his invention) will help solve problems with electricity supply in third world countries. Let's watch a video about it:
Now look at the photo below. What do you think these people are doing?
These are prisoners, violators of the order of the colony, in one of the Brazilian prisons, instead of a punishment cell, they generate electricity. They charge batteries that are used to power Santa Rita's lights at night. And the idea was taken by the head of this institution in the women's prison in Phoenix (Arizona, USA). There, convicts pedal for 16 hours a day, and this counts towards their 24-hour sentence. This way they shorten their time.
Where can a bicycle electric generator be used in our everyday life?
You can, for example, charge your phone while exercising in the morning. Well, really, why not exercise and save energy at the same time? Measure how long it takes to charge your cell phone. Try to remember the time and try to beat it in the future.
You can combine business with pleasure, so to speak - see if you can generate as much energy as the blender consumes. Then you can make yourself a sports cocktail.
If you have a technically adventurous child, why not try bringing this idea to life just for the experience.
Use your imagination and maybe some other funny ideas will come to your mind.
It is possible that you will want to bring your ideas to life. What do you need for this?
If you do not plan to connect anything other than a DC light bulb to this device, then you can do without the last three points.
And they will be needed to connect other electrical appliances. The reason for this is the uneven voltage that will come from the generator (electric motor).
Let's get started. I am posting two diagrams for comparison. On the first, the pedal generator can only power DC light bulbs, and on the second, it can fully work with devices designed for 220V AC. Select a scheme.
There is a special device that can generate power energy. Such a device is a bicycle generator. The resulting electricity is absolutely free. The production process occurs by scrolling the pedals. According to the types of bicycle generators, there are 4 types:
The frequency of pedaling is quite closely and almost inextricably linked with the output of current and voltage. This reproduction is typical for all types of generators. The bicycle generator produces only alternating current. To ensure constant current, it is necessary to install a rectifier bridge. It consists of specialized diode lamps. Or you can install a two-half-cycle rectifier. You can buy a generator for a bicycle in special stores, as well as at car markets.
This type of generator is called a bus generator. By type it is a secondary value generator. The bicycle bottle generator consists of a housing that is completely insulated. On the outside there is a special roller that is designed for rotation. It is tightly attached to the body, that is, to the plug. Also, the filling of this generator consists of a conventional copper winding and a magnet. The movement of a field of magnetic origin occurs due to the contact of the roller with the tire of the bicycle wheel. Based on this, energy is transferred from the wheel to the mechanics.
The faster the wheel rotates, the faster the roller on the generator rotates. Maximum polarity is achieved in the generator itself, and voltage is reproduced.
The positive side of this type of generator is:
As for the shortcomings, they are not so significant:
But taking into account these disadvantages and advantages, in general, this type of generator is quite effective.
Electricity is supplied through the operation of a bottle generator. The carriage also produces current. In another way, this type of bicycle generator is called a hub dynamo. The name comes from the fact that there is no contact between the generator and the wheel. The current appears as a result of close contact of the rim to the generator. This is what causes the magnetized field of the wheel rim to form.
The lighting diode is directly installed in the device. The voltage goes directly, without any additional stabilization devices. The positive aspects of this device are:
The headlight, which is located at the front, is installed on the fork. Taillight - rear. Based on this, these flashlights are independent in themselves. They burn not due to batteries, but due to the rotation of the wheel in a magnetic field. The quality of lighting is at a sufficient level. When riding a bicycle in slow motion, the lights should go out, but this is not the case. This does not happen due to the fact that a special capacitor is installed. In essence, it can be called a battery that gains energy while riding a bicycle.
Using a bicycle generator is beneficial. Firstly, absolutely free electricity generation. Secondly, convenient and comfortable road lighting at night. The 12 volt DC bicycle generator is convenient to use and easy to install. It can also be assembled almost quickly. Does not take up much space during transportation. A bicycle generator does not cause any harm.
