Hello everyone! I hope you are doing well. In this tutorial, we will study the relay from its basic construction to practical selection and control. A relay allows one electrical circuit to operate contacts in another circuit. This makes it useful when a low-power controller must switch a different voltage, a larger load or an electrically isolated circuit. We will focus first on the common electromechanical relay because its moving contacts make the operating principle easy to understand. We will then compare electromagnetic, reed, solid-state, thermal and hybrid relays, calculate coil current, discuss contact ratings and examine a safe microcontroller driver. A relay is often described as an automatic switch, but that short definition hides several important details. The coil and contact ...
Hello friends! In this tutorial, we will design an LED blinking project using the PIC16F877A microcontroller. It is a simple project, but it introduces several ideas that appear in almost every embedded system: configuring an I/O port, choosing an oscillator, building a reset circuit, calculating LED resistors, generating a time delay, compiling a program, and loading the resulting HEX file into Proteus. We will connect eight LEDs to PORTB and switch the complete port between logic low and logic high. Once this basic version works, you can change the output patterns and timing to create a running light, binary counter, or status display. The important objective is to understand why every connection and every program statement is present. Figure: The original simulation shows the PORTB LED ...
Hello friends! We have already covered the Introduction to XBee Module and Interfacing of XBee with Computer . In this tutorial, we will connect our configured radios to two Arduino UNO Rev3 boards and use a pushbutton on one board to control the built-in LED on the other. We will build the project in stages. First, we will establish the power and serial connections. Next, we will define the messages sent between the boards. Finally, we will write separate sender and receiver sketches and examine how they handle button bounce, incomplete messages, and a lost wireless connection. The example assumes two compatible radios already configured for transparent serial communication at 9600 baud. The address values carried forward from the previous lesson apply to classic S1 802.15.4 firmware. Rad ...
