In our earlier article, We have discussed PWM and informed you that this PWD technology is used in particular for light-emitting diodes (LEDs), as they are often used as backlights on mobile phones or brake lights in newer motor vehicles. Our older article on Breathing LED also uses PWM. This was the sketch, LED is attached to pin 11: [crayon-650f5b6aaf86d699730833/] This article is … [Read more...]
What is Pulse Width Modulation (PWM)?
Pulse Width Modulation (PWM) or Pulse Duration Modulation is a type of modulation in which a technical quantity of electrical voltage changes between two values. At a constant frequency, the duty cycle of a square wave pulse is modulated, i.e. the duration of the pulses forming it. It is used to generate a pseudo-analog signal from a digital or analog environment to allow processing of this signal … [Read more...]
What is General-Purpose Input/Output (GPIO)?
GPIO (General Purpose Input/Output) ports are I/O ports widely used in the world of microcontrollers, especially in the field of embedded electronics. Usage of this term appeared in the early 80s. GPIO are placed on an electronic circuit in order to communicate with electronic components and external circuits. These can be detectors or sensors to capture data, or to control commands. GPIO contacts … [Read more...]
Toggle Button Status Update (PHP, MySQL, AJAX)
Our This guide ESP32 Arduino IoT Relay Control is self-hosted. The working result is here. This kind of project serves the purpose but the UI is just pathetic and you can not easily convert it to an Android or iOS app. Most of us want a working system to get a toggle button control like this one. These days, you have a lot of options for UI such as React.js or just Twitter Bootstrap. You have … [Read more...]
What is Cathodoluminescence?
Cathodoluminescence is a special form of luminescence in which an electron beam coming from an electron source hits a solid surface and stimulates it to emit light, i.e. electromagnetic radiation (functional principle of cathode ray tube). In geology, mineralogy and materials science, an optical cathodoluminescence microscope is used to visualize internal structures of rock samples, ceramic … [Read more...]
Arduino TDA7297 Audio Amplifier Module (for Doorbell)
Our Arduino project on doorbell is a great, simple project but if you followed that guide, you have probably noticed the volume of the sound that we are generating using a buzzer or speaker connected to an Arduino is not enough loud to be useful as a doorbell. That's why we need to slightly modify such projects and amplify the sound. TDA7297 amplifier module can be powered by 6-18V and is … [Read more...]
Arduino LED Blinks with Pushbutton Pause
We have published several simple articles on Arduino, LED and pushbuttons. They are a great learning tool for the children, as well as great "templates" for the adults to start a new project. Here is a list of some of the old articles: Arduino 2 Push Button One LED: Switch On/Off Make Beep Sound in Arduino Project Upon Push Button Press Arduino Blink LED Rate Depending On Push Button … [Read more...]
How to Create a PHP Installer Script to Create Tables in MySQL Database
When we need to create a small dynamic web application, using PHP and MySQL are our obvious options. When we need to create a self-hosted IoT solution like this guide ESP32 Arduino IoT Relay Control, either we need to instruct the user to create a MySQL database, create tables and populate with data or we can create an installer script so that the job is "automatically" done. When we install … [Read more...]
GC9A01 Round LCD Module for ESP32 and Arduino
If you looking to build a smartwatch then GC9A01 round LCD module is not the ready-to-use solution for you. The company Waveshare sells one unit with this display with integrated Raspberry Pi RP2040, accelerometer and gyroscope sensor. That is called RP2040-LCD-1.28 and the unit costs 1.5 times more than this GC9A01 round LCD module. This is the product description of that RP2040-LCD-1.28 … [Read more...]
ESP32 Arduino Water Tank Level Monitoring Using Laser ToF Sensor
Guides for building a DIY water level monitoring system using Ultrasonic Sensor and ESP32 or Arduino UNO are quite common. In real life, using an Ultrasonic Sensor for a water tank is often not practical because a water tank can have 1-2 sources of water falling to fill up the tank from the top. Also, with Ultrasonic Sensor, you need to make sure that the position of the sensor is optimum in a way … [Read more...]
Laser Security System Using ESP32 Arduino
Laser tripwire-based security systems use low-energy lasers and simple technology to trigger the alarm system. This alarm can be auditory, visual or mobile notification via IoT based system. These systems are completely legal in any country till the laser rays are not disturbing the public. On the other hand, a laser fence or laser wall uses a high energy laser (cutting laser) to injure bodies … [Read more...]