By T.K. Hareendran

International Electronic Design Freelancer • Technical Author • Hardware βeta Tester • Product Reviewer
Articles Written 469

Mini Solar Garden/Street Light

Here’s another do it yourself project of an automatic mini solar garden/street light. This design belongs to the ‘renewable energy’ category, and is wired around a handful of inexpensive electronic parts. This nifty light circuit […]

Active Heat sink Fan Controller

Active heat sink fan controller presented here is a very simple yet highly useful circuit for automatic control of cooling fans in active heat sink units. The circuit is realized using easy-to-use inexpensive parts and […]

Stand-alone PWM Power Driver

Do you remember the feeling of building your own power electronics projects with a nifty analog chip? Something like DC-AC power inverter based on the SG3525? The SG3525A is a pulse width modulator integrated circuit […]

TL431 & Li-Ion Battery

TL431 is a cheap ‘n’ cheerful yet reliable programmable precision shunt regulator chip available in 3-pin TO-92 package. This monolithic IC voltage reference operates as a low temperature coefficient zener which is programmable from Vref […]

USB OTG Power Guard

As you may well know, you can borrow USB standard 5 volt dc supply from any smartphone equipped with USB on-the-go (USB OTG) port. USB OTG is a hardware (and software) standard that allows you […]

Universal 2S Li-Ion/LiPo Charger Module

This is a simple and 100% safe universal linear charger module for 2S Lithium-Ion (Li-Ion) and Lithium-Polymer (LiPo) batteries with the recommended constant-current/constant-voltage (CC/CV) charging algorithm. Initially charging takes place in the current mode and […]

Little Rescue Light

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 […]

Simple Wireless Door Bell

Here’s an interesting circuit of a wireless door bell/buzzer for electronics students and hobbyists. The circuit is a short-range radio-frequency (RF) tone generator realized with the help of a cheap 433MHz RF transmitter & receiver […]

Tiny Tone Decoder Module

I’d made a number of tone decoder projects with the unique NE567 PLL tone decoder chip in 1990s, and most were published in Elektor Electronics (UK), Silicon Chip (AU) and Electronics For You (IN) magazines. […]