LED matrix displays provide flexibility to display text, graphics, animations, and video, and therefore, they have become a popular mean of displaying information these days. You can see them at gas stations displaying the gas prices, or in the public places displaying information, and alongside highways displaying advertisements on large dot matrix panels. This project is about constructing a mono-color LED matrix display board that consists 320 LEDs arranged in 8 rows and 40 columns. The heart of this project is PIC16F1847 microcontroller which receives data from a PC through a serial port (or USB using an USB-UART interface), and display on the LED matrix with the help of five 74HC595 shift registers.
Tag Archives: PIC16F1847
This mini breakout board is designed to simplify prototyping and experimentation work with the popular 18-pin PIC16F series microcontrollers. It is small in size (1.95″ X 0.75″) and is breadboard friendly.
It supports PIC16F84A, PIC16F628A, PIC16F88, PIC16F648A, PIC16F1827, PIC16F1847, and other 18-pin microcontrollers in the same series. Read more
This is an improved version of my 18-pin PIC16F series breadboard module that I have used in many of my PIC tutorials and projects published in this website. The new version has got a +5V power supply regulator on-board and a 2.1mm female barrel jack for DC input from a wall adapter. The 18-pin PIC16F series microcontrollers are still very popular among hobbyists and beginners because of their compact size, low cost, and simplicity. The PIC16F1847 is the latest release in this series and is equipped with lot more peripherals and enhanced features than its predecessors. This breakout board will be helpful for rapid prototyping with the PIC16F1847 microcontroller. Since the predecessors of PIC16F1847 share the same pin configuration, this board can also be used with popular PIC16F84A, PIC16F628A, and PIC16F88 microcontrollers of the same series.
In the first part of this discussion, the features of ACS712 device were briefly discussed. Now we will use that theory to implement the ACS712 sensor to make a simple DC current meter. The analog output voltage from the sensor is measured through an ADC channel of the PIC16F1847 microcontroller. A voltage to current conversion equation will be derived and implemented in the firmware of the PIC microcontroller and the actual load current will be displayed on a character LCD.
Sensing and controlling current flow is a fundamental requirement in a wide variety of applications including, over-current protection circuits, battery chargers, switching mode power supplies, digital watt meters, programmable current sources, etc. One of the simplest techniques of sensing current is to place a small value resistance (also known as Shunt resistor) in between the load and the ground and measure the voltage drop across it, which in fact, is proportional to the current flowing through it. Whereas this technique is easy and straightforward to implement, it may not be very precise because the value of the shunt resistor slightly varies with its temperature, which in fact is not constant because of the Joule heating. Besides, this simple technique does not provide an isolation between the load and current sensing unit, which is desirable in applications involving high voltage loads. Today, we will talk about Allegro ACS712 device which provides an economical and precise way of sensing AC and DC currents based on Hall-effect. This discussion is divided into two parts. The first part will provide a brief overview of the ACS712 sensor and its characteristics. In the second part, a test experiment will be carried out to interface the sensor with a PIC microcontroller to measure a dc current.