Recently I got an unusual query from a newbie microcontroller hobbyist on how to drive an electromagnetic relay using a bipolar junction transistor (BJT). Admit it, analog electronics is not a piece of butter cake for the most except a few willing scholars! Say you wanted to drive a 5V/70mA rated electromagnetic relay by one… [Read More]
Microcontroller Basics
Wearables and dozens of real time applications use a microcontroller other than a microprocessor for their core design of the entire product. And, these days almost every electronic device comes with a microcontroller. Most of the embedded applications make use of a microcontroller unit (MCU) to perform computing operations and Boolean functions. This article covers… [Read More]
Ultrasonic Water Level Monitor
Here’s a little idea to monitor the level of water in a water tank with the help of an ultrasonic sensor module. The build process is very simple, and best understood by referring to the hardware setup diagram. The technique behind this idea is easy to understand. The ultrasonic sensor sends out an ultrasonic pulse,… [Read More]
Simple Selfie Light
Let me introduce another minimalistic circuit of a simple Selfie light based on generally available low-cost components. The idea presented here is a compact USB chargeable design with inbuilt rechargeable battery and dedicated battery charger circuit. After successful construction you can put the whole electronics into a beautiful handmade or 3D printed translucent enclosure. Key… [Read More]
Solar LED Road Stud
Let me start this month with a Solar LED Road Stud project. Solar LED road stud is a self-powered, autonomous device usually installed on the center line of a road, the lane boundary, and crosswalks to clearly guide drivers and pedestrians in nighttime, rainy or foggy weather. Solar LED road stud charges its rechargeable battery… [Read More]
Hack Your 16×2 LCD
Nowadays most popular microcontrollers are working on 3.3V but many liquid crystal displays (LCDs) for them are usually on 5V, because they are centered on Hitachi’s de facto standard LCD controller – the HD44780 chip. Presented here is a simple yet effective trick to convert the standard 5V type LCD to a 3.3V one! As… [Read More]
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 has two key components: a solar panel with a peak output voltage of about 6 V, and a Li-Ion battery… [Read More]
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 the design is centered around a standard 10K NTC thermistor. See the tried and tested circuit diagram of the 12V… [Read More]
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 designed to offer improved performance and lowered external parts count when used in designing all types of switching power supplies…. [Read More]
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 to 36 V with only two external resistors. In this article, you can find two simple circuits built around the… [Read More]
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