By T.K. Hareendran

International Electronic Design Freelancer • Technical Author • Hardware βeta Tester • Product Reviewer
Articles Written 464

Poor man’s 433MHz RF Sniffer

Nowadays minuscule 433MHz RF modules are used in a wide variety of applications that require wireless control, and are very popular among the tinkerers because these modules are very cheap and can be interfaced easily […]

Secure Water Pump Switch

Here is the circuit diagram of an independent water pump switch controller with ‘soft’ on/off buttons. Since the circuit uses low-voltage switches, even a kid can operate it safely. Besides, there’s also a dry-run protection […]

Safe Bathroom Lamp Controller

As you may know, bathroom is possibly the most dangerous area in your house when it comes to electrical safety because water is a sound electrical conductor. The consequence of an electric shock is far […]

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) […]

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 […]

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) […]

Unique Electric Heater Controller

Circuit of a little solid-state heater controller is described here. This circuit can be used to regulate standard resistive heating coils widely used in AC230V grid supply powered heating gadgets like Air Heaters, Hot Air […]

White LED Bulb AC230V

Presented here is a simple yet useful AC230V White LED light bulb with an isolated digital interface to control its on/off switching actions through a microcontroller or an external electronic circuitry. The design is based […]

Automatic LED Night Light

Inspired by a Chinese design, recently I built a small automatic LED night light with the help of a few generally available inexpensive components. Shown below is the base schematic of that automatic White LED […]