In festival days, we switch ON the lights of our corridor, balconies or staircase. In the case when people have lighting done at two different locations, they have to go to two different places to switch ON the light but, with the help of this circuit, you can switch ON both the lights with a simple touch. This simple two way switch circuit is built around CD4013 which has two independent flip flops on a single chip and each module is further equipped with a group of pin outs assigned as data, set, reset, clock input and a couple complementary output Q and NOT Q. CD4013 is a 14 pin IC which contains two independent sets of flip flops and in our circuit we are utilizing both. Image below shows the pin diagram of the IC:
Fig. 1: Pin Diagram Of CD4013 IC
In the two way switch circuit diagram, Pin 3 and 11 serve as Clock input and receive clock signals generally in the form of square wave. These signals may be provided by the transistor in the form of astable multivibrator or with the help of NAND gate or by NOR gate. This input will produce effect on any of the output pin, the other being connected to Data pin. Here we will receive the input signals from touch pad. However, these signals are very weak, so we have used transistor (BC557) to amplify them. Therefore, when you touch the touch pad, you have provide a clock pulse to pin 3 and 11 which in turn provides a high transition to output pin 1 and 13. These pins further turn on the transistor which energizes the relay and the device connected through it start working.
Pin 5 and 9 are Data pins which are generally connected to one of the output . For the purpose of lengthening, the applied input clock for square wave and for other waves may be terminated to any other logic level. For this purpose, data pins may either be connected to supply or to the ground of the circuit. In our circuit we have connected Q1(NOT) and Q2(NOT) to Data pin 5 and 9. Combination of C1, R3 is connected to pin 4 and C2, R5 are connected to pin 10 are used to provide power ‘ON’ reset.
If you want to make a touch sensor at your home than take conducting plate (it may be copper) and glue it to some non-conducting material like wood or plastic in a close proximity to each other. So when we touch the sensor with the tip of our finger, circuit starts working. You can also find a ready-made sensor available in market or you can use push to on switch.
Filed Under: Electronic Projects