Here is a modified and improved electronic lock design. For Arduino version click here.It is largely based on Digital Lock article, however this time a real electronic lock was used instead of a solenoid. The code is a 4 digit number ...

In this post I'll show you how two QDSP-L149 5x7 dot matrix  LED Displays can be used to create a  4 Digit display module. The trick is to change  the roles of rows and columns. So now each 5x7 Dot ...

MAX7219 is a serial input/output common-cathode display driver. It can interface the microcontroller to 7-segment numeric LED displays, bar-graph displays, dot matrix display or  individual LEDs. This IC has some very useful features like built in decoder, multiplex scan circuitry, ...

In this article I’ll demonstrate a digital stopwatch design based on PIC16F876A micro controller.For related circuit based on Arduino click here. Similar project showing a Digital Timer design can be found here. Current circuit can be used to count in ...

Interfacing LCD Display with serial Interface like I2C can save microcontroller I/O making it a practical alternative to a standard parallel 8 bit interface. We’ll use PCF8574 I2C port expander and PIC16F876A microcontroller to establish IIC communication by 2 lines, ...

In this post we’ll review a simple interface for PCF8574 I2C 8-bit IO expander IC and PIC microcontroller. For similar Arduino based implementation click this link. The format of present post is similar to 2 recently published tutorials about I2C ...

Relay controlled by light intensity can be implemented using Arduino UNO compatible board. In this case Keyestudio UNO R3 and AD/DA module with PCF8591 chip. Similar simpler design is available here. On this particular module a photoresistor and a potentiometer ...

Using HC-SR04 Ultrasonic Sensor with Raspberry Pi is a relatively easy task. HC-SR04 is a very popular module that can provide the distance to the object by sending ultrasonic bursts at 40kHz and measuring the time it takes for the ...

Have you ever wondered how to generate a sine wave using PIC microcontroller. In this post I’ll show you a simple circuit design that can generate arbitrary wave forms including sine by using MCU and PCF8591 D/A converter. For similar design ...

3 Digit Up Down Counter shown here is based on PIC16F877A microcontroller. The count is shown on the 2x16 LCD display and the direction is controlled by a switch connected to bit 3 of PORTA. With minimal changes the attached ...