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How to use Capacitive Touch Sensor in Proteus Schematic Circuit Diagram

Today, I’m excited to present a tutorial for my latest project: How to utilize a Capacitive Touch Sensor in Proteus ISIS. This project is particularly intriguing as it involves the incorporation of a 555 Timer during the design process. If you remember our previous project tutorial, we explored the Angle Control of a Servo Motor using a 555 Timer in Proteus ISIS. In that project, the 555 timer generated PWM signals, effectively managing the servo motor’s rotational angle.

How to use Capacitive Touch Sensor in Proteus Schematic Circuit Diagram 1

In this project, our focus shifts slightly as we delve into the collaboration between a 555 Timer and a Capacitive Touch Sensor. First, let’s briefly introduce the concept of a Capacitive Touch Sensor. In the realm of Electrical Engineering, Capacitive Touch Sensing utilizes technology based on Capacitive Coupling. This technique harnesses the capacitance of the human body as an input and detects anything conductive, possessing a potential difference, or even static objects with dielectric differences from air.

The technology involves coating one side of an insulator with conductive material and applying a minimal voltage to this layer. This voltage creates a uniform electrostatic field. When a conductor, such as a human finger, enters this field or touches the non-coated side of the insulating material, a dynamic capacitor is formed. If there’s a high potential difference between the bodies, current begins to flow. That provides a basic understanding of the Capacitive Touch Sensor. Now, let’s transition from theory to practical application and explore the hardware aspect of the aforementioned tutorial.

You can download the complete simulation of above described project by simply clicking on the link given below:


How to use Capacitive Touch Sensor in Proteus

  • In this project, we are using 555 Timer in collaboration with Capacitive Touch Sensor. A 555 timer is an 8 pin IC. Pin # 6 is called threshold pin and for 555 timer threshold level is 5 volts.
  • So, 555 timer will trigger above 5 volts and it will generate output which can be collected from pin # 3 represented as ‘Q’ which is output pin of 555 timer.
  • While moving toward the simulation of project, first of all place all the components in the proteus workspace, as shown in the image given below:

How to use Capacitive Touch Sensor in Proteus Schematic Circuit Diagram 2

  • First of all we have place Capacitive Touch Sensor and after that we have placed a NPN transistor, then 555 Timer will come and at the output of 555 Timer we have added a LED. The complete circuit diagram ready for simulation is shown in the image given below:

How to use Capacitive Touch Sensor in Proteus Schematic Circuit Diagram 3

  •  As long as the finger is out of the vicinity of the electrostatic field, no potential difference occurs and the LED remains in the OFF state.
  • Now if we move the finger towards Capacitive Touch Sensor, then and when the potential difference reaches up to 0.6 volts, then 555 triggers and it generates output voltages across LED which are 5 volts but in some cases voltages are lost due to series connected resistances. This phenomenon is shown in below image:

How to use Capacitive Touch Sensor in Proteus Schematic Circuit Diagram 4

  • Now if we further move the finger and take it completely near the sensor. Then at this point max potential difference will occur between both point (finger and conductive layer). An important thing to note here is that, we have change the location of our interrupt ( finger). But same voltages are appearing across LED which are 4.91 volts in this case. It can also seen in the figure given below:

How to use Capacitive Touch Sensor in Proteus Schematic Circuit Diagram 5

  • Now, if we summarize the whole project, we have seen that the movement of finger is in fact controlling our output. When the finger was out of vicinity of the sensor, then LED was OFF. When we moved the finger in forward direction and came in the vicinity of Electrostatic field, then Sensor gives signal to 555 Timer and Timer makes LED to glow.
  • Here’s a video demonstrating Capacitive Touch Sensor in Proteus ISIS.

Applications Of Capacitive Touch Sensor

In today’s digital landscape, capacitive sensing touchscreens have become prevalent features in devices such as digital audio players, mobile phones, and tablet computers. These sensors possess the capability to supplant mechanical buttons, providing a more streamlined and intuitive user experience. Interestingly, the concept of capacitive touch control dates back to 1928 when Russians invented the “Theremin,” A musical instrument that allowed players to control volume and pitch without any physical contact with the instrument.

While capacitive touch sensors may seem fundamental. They serve as the foundation for extensive industrial projects. Moreover, they are instrumental in the development of various other sensors, playing a pivotal role in enhancing technology and user interfaces.

  1. Position sensor.
  2. Humidity sensor.
  3. Fluid or Water level sensor.
  4. Proximity sensor etc..

Alright friends, that’s all for today. I hope I have conveyed some knowledge and helped you people in some way. If you have some queries, then ask in comments. Subscribe us via email to get these tutorials straight in your inbox. Till next tutorial, take care and be safe !!! ?


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