THE SPECIALITIES OF PROJECT
This is a simple Project. Many type of electronic devices can be put ON and OFF with this.
TECHNICAL DESCRIPTION AND WORKING OF THE PROJECT
This project has been developed and tested by our readers and sent to the “T.V.Engineers Technical lab” for publication in the book. The spare parts and PCB of the projects published in the series of our book publication or available in the market. The information of project code is given in the first and last page of the books.
In this project Piezoelectric diaphragm is used as a hit switch. It works as a sensor. When it is triggered with hand it gives electric voltage which is amplified through the transistor T1 DC547. The bridge rectifier D1-D4 and transistor T1 together works as a voltage switch. IC CD4069 is a HEX inverter. Three gates N1,N2 and N3 are used. In the start the input of N1 is low and the input of gate No.N2 is high. When hit switch is knocked then the input level of gate N1 goes high. The condenser C1(0.1MFD) gets charged through resistance R1(56k). It maintains this condition unless voltage control switch does not get next triggering pulse. The LED connected at the output of gate No.3 shows the ON/OFF position and load is controlled by relay.
This circuit works on 12V DC. The proper installation of hit switch is very necessary. It is fixed at such a place where it is easy to knock it.
PRECAUTIONS WHILE MAKING THE PROJECT
- Do the proper wiring of Piezobuzzer after removing its cover.
- Press the hit switch lightly otherwise it may get damaged.
- Use the IC base while connecting IC in the circuit.
Check the components before connecting on PCB