In this article I have explained how to connect and use the TTP223 capacitive touch switch module. These modules work using 2.5V to 5V. They are all pre-debounced, all you need is to provide the DC supply across the VC and GND terminals, and you get an output in the middle. So it is really […]
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Ultrasonic Smart Automatic ON/OFF Switch Circuit
In this article we are going to build a smart automatic ON/OFF switch using Arduino, which can turn on or off gadgets automatically by sensing the presence of human nearby through the concept of ultrasonic. We are going to use ultrasonic module and Arduino to sense the presence of human which activates the gadgets such […]
How Switch Mode Power Supply (SMPS) Circuits Work
SMPS is the acronym of the word Switch Mode Power Supply. The name clearly suggests that the concept has something or entirely to do with pulses or switching of the employed devices. I have explained how SMPS adapters work for converting mains voltage to a lower DC voltage. Advantage of SMPS Topology In SMPS adapters […]
Temperature Controlled Relay Switch Circuit
In this article I have explained a simple temperature controlled relay circuit which can be switched ON/OFF depending on the temperature on its temperature sensor. Meaning, when the temperature on its temperature sensor rises above a set threshold point, the relay switches ON, and when the temperature drops below the threshold, the relay switches OFF. […]
Whistle Activated Switch Circuit
In this post I have explained how to build a simple whistle sound operated relay circuit, which can be used for switching ON/OFF a 220 V load through whistle sounds. You can consider this circuit to be a whistle operated remote control circuit which will operate a connected load remotely through the sound of whistling. […]
Make this Thermo-Touch Operated Switch Circuit
The circuit explained here employs a rather different approach for implementing a touch operated switch action. Here instead of the resistance, the warmth of the finger is used for sensing and operating the circuit’s output. Irrespective of the ambient conditions, our hands and fingers mostly exhibits some extra warmth or increase in the level of […]





