In this post I have explained how to interface a 4×4 keypad with Arduino. We are going to see what is a keypad, how it is constructed and a how to program the Arduino to receive keystrokes form the keypad and print them in serial monitor. What is a keypad? A keypad is a portable […]
Archives for 2016
How to Make LED Air Pollution Meter Circuit with Arduino
In this project I will show how to construct an air pollution meter using MQ-135 sensor and arduino. The pollution level in the air is indicated by series of 12 LED. If higher the number of LEDs glows, the higher the pollution content in the air and vice versa. Overview This project can prove […]
GSM Fire SMS Alert Project
In this article I will show how to construct a GSM fire alert circuit system using Arduino and DHT11 sensor, which will alert the user via text message (SMS), regarding a fire hazard within the premise where it is installed. Using DHT11 Sensor We are using DHT11 sensor for sensing unusual temperature rise around the […]
How an Accelerometer Works
In this post I will try to explain how an accelerometer works and also learn the specifications of a popular accelerometer ADXL335 in detail. If you are a tech enthusiast you would have came across the term called “Accelerometer”. This piece of technology made our smart phones really smart, many common home appliances, automobile, robotics, […]
Switching Two Alternate Loads ON/OFF with IC 555
In this post I have explained how to make a simple IC 555 based alternate relay timer circuit for toggling a couple of loads alternately with a specified length of delay, as determined by the calculated values of the relevant components. The idea was requested by Mr. Sanjoy. Circuit Objectives and Requirements The Design Referring […]
Simple Faraday Flashlight – Circuit Diagram and Working
In this article I will show how to construct a Faraday flashlight circuit using only a coil/magnet assembly which requires no battery. It’s not free energy, but it converts oscillatory motion to electricity, which can power the flashlight for a couple of minutes. This flashlight will be useful in emergency situations where no access to […]





