Introduction: Easy Cheap 16F84 POV Message - AirText

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This is a post of LEDs project. The project is called POV (Persistence Of Vision). If you are not familiar with this concept, it works as an LED matrix display.

The difference is that POV display consists of one column of LEDs only and is mechanically scanned through space to give the vision of a 2D LED Matrix Display.

Many projects are built in rotating ( circular motion ) or in oscillating layout ( moving left and right) .

I 've seen this project "AirText " based on the Sun Microsystems Sun Spot , then I wanted to make a similar yet more simple project.

There are many Microcontroller projects based on the POV concept. But i think this is the simplest circuit that can do the job with minimum hardware.

Here is my Channel on Youtube:


Step 1: Circuit


Small piece of veroboard get it from Amazon or from eBay Here

16F84A get it from Amazon or from eBay Here

8 LEDs OF any color you prefer get it from Amazon or from eBay Here

8Mhz Crystal get it from Amazon or from eBay Here

9v Battery Connector get it from Amazon or from eBay Here

9v Battery get it from Amazon or from eBay Here

Small wires


Soldering iron get it from Amazon or from eBay Here

Step 2: Software

Copy the files of the Proteus ISIS design

Compile the C file .

Load the Hex file into the Microcontroller using the 16F84 JDM Programmer. In another instructable of mine

You can change the program as you wish to change the drawn text .

Step 3: Run Your AirText

The only drawback with this circuit is that it has no sensor for direction of motion. The
Sun Microsystems Sun Spot has a built in motion sensor called accelerometer. Which senses the amplitude and direction of acceleration. So when the module is moved in one direction it draws the scanned characters according to this direction.

But with this simple circuit using PIC16F84, the characters are drawn in one direction independently of the circuit direction of motion.

Here is the project on my blog:


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