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 […]
Detector
Simple Peak Detector Circuit to Detect and Hold Peak Voltage Levels
In this article I have explained about a peak detector circuit, its working principle and how to implement it in clap operated circuits for illuminating an LED in response to clap sounds. What is Peak Detector A peak detector is a circuit which holds maximum amplitude value of a signal. If a signal varies rapidly […]
Simple LDR Motion Detector Alarm Circuit
Here I have explained how to build a simple LDR based motion detector sensor circuit using ordinary parts such as LDRs and opamps, reasonably accurately. What are Motion Detectors Motion detector or sensor alarm is a device which detects the presence of a motion or movement within a certain fixed range and raises an alarm […]
Ultrasonic Detector Circuit [Extend your Ear’s Sensitivity]
The ultrasonic detector or receiver circuit will be able to detect all those high frequency sounds that are beyond the hearing capacity of humans. The units will be able to hear all those frequencies that are perhaps only audible to some animals like dogs, cats and bats. The ultrasonic receiver circuit can be used for […]
Anti Spy RF Detector Circuit – Wireless Bug Detector
A anti-spy or bug detector circuit is a device that detects hidden wireless electronic devices such as wireless microphones, spy cameras, Wi-Fi devices, GPS trackers or any gadget that emits some kind of radio frequency (RF). The proposed design can be specifically used as: Overview Also called anti spy RF sniffer, these are usually used […]
9 Simple Metal Detector Circuits Explained
In this post I have explained 9 simple metal detector circuits using LC tuned concept, magnetic absorption concept, and the beat frequency oscillator (BFO) concept. The BFO technique is considered to be the most accurate and reliable methods of detecting metals. 1) Metal Detector Circuit Using a Single UJT The first metal detector circuit shown […]