Foot step power generation is a new way to generate power without any fuel and can be very use full. Here piezoelectric crystal is use to generate electrical energy throughout presser and then it will store in the battery.
As we know From the last few years the increasing demand of low power portable devices rapidly. Due to increase in in demand of energy consumption for the devices we have to think over the alternative renewable energy in human surroundings. So, either we need a long lasting battery or a smaller power generator which uses human power to generate electricity and feed the device. For this, Piezoelectric Effect is the best example to produce electricity by using the footstep power of the human body.
What is Piezoelectric Effect?
Piezoelectric Effect is the ability of certain materials to generate an electric charge in response to applied mechanical stress. The word Piezoelectric is derived from the Greek piezein, which means to squeeze or press, and piezo, which is Greek for “push”.
When piezoelectric material is placed under mechanical stress, a shifting of the positive and negative charge centers in the material takes place, which then results in an external electrical field. When reversed, an outer electrical field either stretches or compresses the piezoelectric material.
Circuit Diagram for Foot step power generation
A piezoelectric sensor is made up of piezoelectric material (quartz-most used). It used to convert the mechanical stress into electrical charge. The output of the Piezoelectric Sensor is AC. We need a full bridge rectifier to convert it into DC. The output voltage of the sensor is less than 30Vp-p, you can feed the output of piezoelectric sensor or can store it into battery or other storage devices. The impedance of the piezoelectric sensor is less than 500 ohm. The operating and storage temperature range is -20°C~+60°C and -30°C~+70°C respectively.
After making connections as per the Piezoelectric Sensor circuit diagram, when we provide mechanical stress to the piezoelectric sensor it generates voltage. The output of the piezoelectric sensor is in AC form. For converting it from AC to DC we are using a full bridge rectifier. The output of the rectifier is connected across a 47uF capacitor. The voltage generated by the piezoelectric sensor get stored in the capacitor. And, when the push-button is pressed all the stored energy is transferred to the LED and LED turns ON till the capacitor get discharged.
In this circuit, the LED is glowing for a fraction of seconds. To increase the ON time of LED you can increase the capacitor rating, but it will take more time to charge. Even, you can connect more piezoelectric sensor in series to generate more electrical energy. Also, the diode is used for blocking the current to flow from capacitor to piezoelectric sensor and the resistor is current limiting resistor. You can also connect a LED directly to the piezoelectric sensor but it will just flash.
List of Piezo materials for foot step
- Natural Piezoelectric Material – Synthetic Piezoelectric Material
- Quartz (most used) – Lead zirconate titanate (PZT)
- Rochelle Salt – Zinc Oxide (ZnO)
- Topaz – Barium Titanate (BaTiO3)
- TB-1 – Piezoelectric ceramics Barium titanate
- TBK-3 – Calcium barium titanate
- Sucrose – Gallium orthophosohate (GaPO4)
- Tendon -Potassium niobate (KNbO3)
- Silk – Lead titanate (PbTiO3)
- Enamel – Lithium tantalite (LiTaO3)
- Dentin – Langasite (La3Ga5SiO14)
- DNA – Sodium tungstate (Na2WO3)
- Ultra-fine focusing of optical assemblies
- Production and detection of sound
- Generation of high voltage
- Electronic Frequency generation
- Everyday applications like cigarette lighters