Abstract: The equipment used mainly adopts the generator as the main body, supplemented by the lever, and is modified and combined into a pedal generator. Add a pinion to the load-bearing part of the generator to install the existing space of the stairs, and connect it to the surface of the stairs through a lever. After people leave, the motor generates electricity for other use. Keywords: generator; Arc lever; Tread 1. introduce

With the development of mankind, the international competition is becoming more and more fierce. The most fundamental thing is to compete for energy, and solving the energy problem is also the basic premise of sustainable development. Therefore, energy is becoming more and more precious, and the desire to seek new energy is also put into action. Moreover, while demanding energy, more and more attention is paid to environmental protection, and the cleanliness of energy has become a major indicator to measure whether energy is available. Compared with the traditional form of power generation, the pedal generator has the advantages of environmental protection and cleanliness, and its way of obtaining energy is more concise, which conforms to the theme of the contemporary era. However, the energy of walking is wasted. In order to make full use of resources, our group specially designed a pedal generator to respond to the call of the times and make its due contribution to society!

2. Experimental scheme (design concept

In this experiment, generators, arc levers, conductors, springs, shrapnel and auxiliary equipment are used. After the completed pedal generator is placed at the designated stair position, the arc rod is fixed at the folding point of the two steps. The lever is divided into pedal, fulcrum, lever arm and sawtooth plate, and the sawtooth plate is meshed with the generator gear. When the pedal is stepped down and moves down, the lever will transfer and expand the range of motion, thus maximizing the power generation efficiency of the generator. In order to ensure that the sawtooth of the lever can fully contact with the gear and will not be separated from the gear due to the circular motion of the sawtooth, a spring is added behind the generator. The power output end of the generator is equipped with two storage batteries. When the pedal moves, the generator shrapnel contacts different batteries to store current in different directions. Install a suitable spring system under the pedal, and the height from the pedal surface is about 4 cm. The tread and other materials may be insulating materials.

Experimental steps: (1) Connect the completed equipment as shown in the figure.

Step side view

The general plan 1 shows that the gear meshing position 2 is the generator and the spring 3 is the current conversion chute.

No.4 and No.5 are storage batteries, and the storage directions are opposite.

flow

Generator side view

Thesis of the 4th Physics Comprehensive Design and Science and Technology Innovation Competition of Chongqing Jiaotong University

2

In the top view of the generator, the function of the spring is to keep the two gears in a good meshing state.

Top view of current steering

Side view of the diverter

Two copper plates connecting the anode and cathode are connected to the end of the lever, and the lever moves with the vertical rack.

(2) Treadmill test. When walking normally, when stepping on the tread, the vertical deformation of the tread is d 1. Through the calculation of arc lever, we can know the rotation of generator gear. (3) Test the generated voltage. Connect a voltmeter to the connected equipment to measure the voltage generated by the rotation of the gear in different directions respectively.

(4) Utilize the electric energy generated by the generator. Experiments show that the energy stored in the battery can be applied to some low-power electrical appliances.

3. Results and discussion

A single pedal generator generates less electricity, but when it is used in a large number of stairs, it will generate a lot of energy, which can be applied to people's daily life. Its application places can be used in schools, hospitals, supermarkets, office buildings and many other public places.

When selecting a level gauge, the following factors should be considered:

(1) measurement objects, such as physical and chemical properties of the measured medium, working pressure and temperature, installation conditions, liquid level change speed, etc.

(2) Measurement and control requirements, such as measurement range, measurement (or control) accuracy, display mode, on-site indication, remote indication, interface with computer, safety and anti-corrosion, reliability and construction convenience.

Commonly used liquid level meters in water supply engineering and their selection points are as follows:

A. float liquid level measuring instrument

Put a hollow floating ball in the liquid. When the liquid level changes, the floating ball will produce the same displacement as the liquid level changes. The displacement of the floating ball can be measured by mechanical or electrical methods, and its accuracy is (1 ~ 2)%. This kind of liquid level gauge is not suitable for high viscosity liquid, and its output end is controlled by switch, which can output continuously.

In the design of water purification plant, this kind of liquid level meter is often used to measure the liquid level of the collecting well to control the automatic start and stop of the drainage pump.

B. Static pressure (or differential pressure) level gauge

Because the static pressure of the liquid column is proportional to the liquid level, the liquid level can be measured by measuring the static pressure of the liquid column on the reference surface with a pressure gauge. Calculate the pressure or differential pressure range according to the density of the measured medium and the measuring range of the liquid, and then select the pressure gauge or differential pressure gauge with appropriate range and accuracy. The accuracy of this level gauge is (0.5 ~ 2)%.

C. radio frequency capacitance level gauge

When electrodes are inserted into the container, when the liquid level changes, the medium inside the electrodes changes, and the capacitance between the electrodes (or between the electrodes and the container wall) also changes, and then it is converted into a standardized DC signal. Its accuracy is (0.5 ~ 1.5)%.

Capacitive level meter has the following advantages: the sensor has no mechanical moving parts and its structure is simple and reliable; High accuracy; The detection end consumes less electric energy and has fast dynamic response; Convenient maintenance and long service life. The disadvantage is that the unstable dielectric constant of the measured liquid will cause errors. Capacitive level gauge is generally used to measure the liquid level in regulating tank and clear water tank.

When the measuring range is less than 2m, rod, plate and coaxial electrodes are used; When it exceeds 2m, use cable electrode. When the measured medium is water, use an electrode with an insulating layer (polyethylene can be used).

D. Ultrasonic level gauge

The sensor of ultrasonic level gauge consists of a pair of transmitting and receiving transducers. The transmitting transducer emits ultrasonic pulses facing the liquid surface, which are reflected from the liquid surface and received by the receiving transducer. According to the time from transmission to reception, the distance from the sensor to the liquid level can be determined, which can be converted into liquid level. Its accuracy is 0.5%.

This kind of liquid level gauge has no mechanical moving parts, high reliability, simple installation, non-contact measurement, and is not affected by liquid viscosity and density, so it is often used for liquid level measurement in medicine tanks, medicine tanks, sludge discharge tanks and so on. However, this method has some blind spots and is expensive.