During an unexpected blackout in particular, a simple light source can be a handy aid. With only two transistors, one photo resistor, and a few other components you can build an automatic emergency light. Here’s the circuit of my recently built, battery operated, little rescue light that lights up automatically in dark times! Circuit Diagram… [Read More]
Electronic Magnet Evaluator
Electronic Magnet Evaluator is a simple device incredibly useful for experimenters and students. With this little gadget one can not only detect the presence of a permanent magnet but also find out its south (S) and north (N) poles. Circuit of this portable device is designed for 9V battery operation. The circuit given below uses… [Read More]
Security System with Voice Playback
This circuit is designed in response to a request made by my beautiful neighbor. What she desired was an inexpensive device to record and replay customized voice messages. Now it’s the frontend of her simple burglar deterrent alarm gear. The battery-operated circuit comprises of two equally important parts – a digital rec/play module (ISD1820) and… [Read More]
Simple Security Alarm Button
Now you can build your own simple security alarm button using a tiny microcontroller chip PIC12F675 ! The circuit is nothing but an aural alert unit, which raises a warning tone when the trigger button is pushed by someone. The unit can be powered from four 1.5V AA/AAA cells wired in series (6VDC). The circuit… [Read More]
Simple Flood Alarm
The electronic flood alarm circuit presented here is wired around an LMC555N (IC1) – CMOS version of the bipolar 555 timer chip. IC1 is followed by a complimentary pair of emitter followers (T1 and T2) to drive a standard 8 ohm loud speaker (LS1). Only one 9 volt alkaline battery is required to power up… [Read More]
3V3 uC Power Supply
Nowadays most electronics hobbyists require a precision 3.3V power supply module for their microcontroller (uC) and/or internet of things (IoT) projects. The traditional linear power supply is not a good choice in many situations because of a number of technical reasons. Well, here is the simplest circuit of a do-it-yourself 3.3V switched buck converter power… [Read More]
Portable LED Tester
The circuit below shows a simple light emitting diode tester, powered from a 9V compact battery,which can be used to test almost all common light emitting diodes (LEDs). Common LEDs require a dc forward bias current of 10 to 20 mA for proper operation (maximum typical dc current is 30 to 50 mA). The color… [Read More]
Efficient Snake Repeller
Solar electronic snake repellent presented here is a proven solution to keep all poisonous snakes out of dog kennels, stables, etc. All you need is to simply place the device on the ground to remove snakes on your property, quickly and safely. Structural details of the standalone, do-it-yourself, solar electronic snake repellent gear is shown… [Read More]
Haptic Feedback Module – DIY
Wearables and dozens of other consumer electronic devices make use of vibro-tactile feedback to enhance the level of user interaction. The most popular hardware frequently used to provide haptic feedback is the ‘Pancake Motor’. Pancake motor is a shaftless vibration motor which can be purchased from almost all online vendors including eBay and Amazon. The… [Read More]
Simple Electronic DC Load
There are a number of solutions for making a simple electronic load – you only have to take a look around the web to see that. This article is a quick guide to building a simple electronic dc load (dummy load) that will be useful for your upcoming power-electronics projects. Join the fun if you… [Read More]