The MQ-135 “air quality” sensor is part of the MQ series of gas sensors that uses a chemical sensitive element. The resistance of such element varies when exposed to certain gases. The MQ-135 is sensitive to multiple gases including Benzene, Acetone, Alcohol and Ammonium.

Flame sensors are found from the simplest gas stoves to huge industrial plants. There are different types of fire sensors — some cheap, some expensive. Yet they’re all built for one single purpose: detect fire. In this article, I will guide you on how to build a flame sensor with …

Last time, I showed you how to setup the ESP32 development board with the Arduino programming environment. This time, I will be building a simple ESP32 web server where data from a sensor is displayed on a web page.

The ESP32 expands the capabilities of the popular ESP8266 WiFi microcontroller by using a 32-bit microprocessor, and adding Bluetooth 4.2 among others.  What possible projects can we build using this device? We will find out as we start our series for the ESP32.

Ever since I wrote about timer interrupts, a number of readers have asked me on how to generate a 16-bit pulse width modulation (PWM) signal with Arduino. Well, here it is.

Current sensors can have different applications: power supplies, over-current protection, and motor control to name a few. In this Arduino current sensor tutorial, we will look at how to read current using the ACS712 sensor.

An Arduino magnetic sensor has several uses: for reading the speed of a rotating object, for door alarms and for navigation. In this tutorial, we will build a simple magnet detector using a hall effect sensor.

In the previous tutorial, we set up a soil moisture sensor and have its data readable via WiFi. However, that data is only accessible if the NodeMCU and the client (smartphone, PC, etc.) is in the same network. In this tutorial, we will use a service that allows us to …

Plants need enough water to survive. But what if you forgot to water the plants? This multi-part tutorial aims to provide a simple soil moisture sensor that reminds you, via WiFi, that your flora needs a shower.

Guest Post from LHDPCB Many buyer have confuse about the price when they buy PCB from the PCB manufacturer , they want to know the factors which affecting the cost of PCB. Let’s learn something about the cost of the PCB.