Foot Step Power Generation Circuit using Piezoelectric Sensor

ByPankaj Khatri 5

Electricity Generation using Piezoelectric Sensor

From the past few years the demand of low power electronic portable devices increasing 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 some piezoelectric materials (such as quartz, topaz, zinc oxide and etc.) to generate an electrical charge in feedback to the mechanical stress. ‘Piezoelectric’ word is derived from the Greek word ‘piezein’ which means to push, squeeze and press.

Piezoelectric Effect

Also, the piezoelectric effect is reversible, which means when we apply mechanical stress to the piezoelectric material we receive some electrical charge on output. And, when we apply electricity to the piezoelectric material, then it compresses or stretch the piezoelectric material.

 

Piezoelectric effect is used in various application that involves

  • Production and detection of sound
  • Generation of high voltage
  • Electronic Frequency generation
  • Microbalances
  • Ultra-fine focusing of optical assemblies
  • Everyday applications like cigarette lighters  

 

Piezoelectric Materials

Number of piezoelectric materials are available now, even natural and man-made. Natural piezoelectric materials include quartz, cane sugar, Rochelle salt, topaz tourmaline and etc. Man-made piezoelectric material includes barium titanate and zirconate titanate. There are some material given in the below table in the category of natural and synthetic:

 

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)

 

Components Required

  • Piezoelectric Sensor
  • LED (Blue)
  • Diode (1N4007)
  • Capacitor (47uF)
  • Resistor (1k)
  • Push-button
  • Connecting Wires
  • Breadboard

 

Foot Step Electricity Generation Circuit Diagram

Circuit diagram for Electricity Generation using Piezoelectric Sensor

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.

Piezoelectric Sensor

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.

Video

Comments

  • Max's picture
    Max
    Jun 26, 2018

    I like this little circuit, however, I do not see the need for diode D1. Is the idea to use a lower leakage diode for D1 compared to the diodes of the rectifier bridge?

  • Jayant's picture
    Jayant
    Jun 28, 2018

    The D1 is mandatory to prevent the capacitor form discharging back into the rectifier bridge 

  • David Ellis's picture
    David Ellis
    Jul 04, 2018

    C1 cannot discharge into the diode bridge because all the diodes in the bridge are reverse-biased when viewed from C1. They are only forward-biased (in pairs) when viewd from the piezoelectric sensor. Max is right.

  • Aldrin's picture
    Aldrin
    Jul 15, 2018

    Can you put another video with full connecting process

Leave a Comment