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 […]
Sensors and Detectors
9 Useful LDR Circuits Explained
In this post I have explained 9 LDR circuit projects that uses LDR light sensor to trigger a load ON/OFF through a relay. These circuits are mostly triggered by the absence or the presence of light on the LDR. The circuits are built using transistors, op amps and LDR along with a switching relay. Let’s […]
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 […]
Automatic PWM Door Open/Close Controller Circuit
In this post I have explained a simple PWM controlled automatic turnstile or door circuit featuring an automatic open/close action via a photo-interrupter stage. The idea was requested by Mr. Bruce Clark. Technical Specifications Thank you for a really fantastic service you provide. Would you please be so kind as to help me with a […]
4 Simple Proximity Sensor Circuits – Using IC LM358, IC LM567, IC 555
Video Demonstration An IR proximity sensor is a device which detects the presence of an object or a human when it is within a predetermined range from the sensor, through reflected infrared beams. Three useful proximity sensor concepts are explained here, the first concept is based on an ordinary opamp LM358, the second one using […]
Home Electromagnetic Radiation Detector Circuit
The assembly proposed in these lines is an electromagnetic radiation detector (power and others) that allows the user to organize their living space with full knowledge. Circuit Description The sensor used for this design is a simple wire coil (L1) associated with the MOSFET transistor (T1) biased at the beginning of its conduction zone by […]