In this article, I will show how to construct a couple of easy Arduino temperature meter circuits which can be also used as a LED room thermometer circuit. The circuit is designed to display the readings in doted/bar LEDs. This project can be implemented for applications where ambient temperature plays a crucial role or it […]
Sensors and Detectors
5 Simple Motion Detector Circuits using PIR
A PIR motion sensor alarm is a device which detects the infrared radiation from a moving human body and triggers an an audible alarm. In this post I have explained 5 simple motion detector circuits using op amp and transistor. We also discuss the pinout details of the standard passive infrared (PIR) sensor RE200B. We […]
Simple Mobile Phone Detector Circuit [Tested]
A cellphone or mobile phone detector is actually a high gain op amp amplifier which detects slightest of RF disturbance from a mobile phone, and illuminates an LED. Mobile phones today being the major generator of RF interference is easily picked up by this circuit and can be seen through an LED illumination at the […]
Non Contact AC Phase Detector Circuit [Tested]
The circuit discussed in this article is of a non-contact mains AC field detector which displays the presence of a mains AC field from a distance of more an 6 inches. Locating Fault in AC Lines without Physical Contact The circuit can be used for locating faults in house wiring without the need of making […]
Simple Digital Clock using LM8650 IC Circuit
The digital time clock explained here is a circuit which most electronic amateurs would love to make. You might have heard about digital clocks made from clock ICs such as the popular LM8361, MM5387 etc but these ICs could be today quite obsolete and/or complex to build. Circuit Operation The present design is much easier […]
How to Make LED/LDR Opto Coupler
Ever needed an application where the resistance of a resistor needed to vary proportionately in response to a PWM or a varying analog voltage? Yes, this is where an LED-LDR opto-coupler becomes so useful. The following image shows the symbol for a LED LDR opto-coupler. Any other regular opto-coupler, such as an LED/transistor, LED/FET, or […]