TOUCH SENSITIVE LED CHASER

8TP017

2B-TOUCH SENSITIVE LED CHASER

 

 

THE SPECIALITIES  OF PROJECT

 

This is a LED chaser circuit. It works by touching the plate. Mostly it is used with door bell school competitions etc.

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.

CMOS ICs 4011 & 4017 are used in the circuit with a transistor BC54c. The working system of the IC is very simple. When we touch the touch plate the transistor T1 BC549c conducts. Due to this gate N1 of IC4011 starts working and its output becomes high. The gate N2 and N3 of IC4011 works as a oscillator. When the output of N1 gate in the circuit is high then the gate N2-N3 starts oscillating. The Pin No.14 of IC2 of 4017 gets the clock pulse. The Pin No.11-15 of the IC4017 are shorted the IC does not get the reset. Due to this LED1-LED9 goes ON-OFF and sequence continues. The LED10 shows that IC4017 is getting pulse. When we remove our hand from the touch plate the clock pulse going to the Pin No.14 of IC4017 stops. The chaser stops working and only 1 LED remains in ON position.

 

PRECATIONS WHILE MAKING THE PROJECT

 

  1. Use base for soldering IC on PCB.
  2. Take Care of polarity of LED when soldering on PCB.
  3. Before putting the project on supply then check the connections and soldering points on PCB.

Use IC base for IC because IC can be spoiled due to leakage from soldering iron.