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LED Matrix Projects.

Thanks for clicking the led matrix extra projects link - I have not yet created all the projects and I need your help.  Obviously it takes some effort to create the content in this site and I want to ensure that you are getting exactly the information you need.  So could you complete the survey at the end of this page?

Thanks very much.

 John...

Project Update:

"Measuring Analogue Voltages

Without An ADC"

( FREE )

Warning: This project could be Removed at
any time and will NOT be available indefinitely.
To avoid disappointment get it Now.


Remember this is a project with full description and fully debugged C Source code - and it's not available from the main website.

You can only get it through this newsletter.

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I promise to use it only to send you MicroZine
Note: Look through the back issues for your
No-ADC method).

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The following is a brief discussion of the project book/course contents:

Projects

With this project set you will learn how to drive the led matrix using interrupts and how to use buffers to scroll the display horizontally and vertically.

Project examples :
  • Interrupt driven display 0-99 (introduction to interrupt refresh).
  • Display buffered refresh for scrolling message display.
  • Temperature display.
  • Binary clock.
  • DVM with scale bar with (opamp front end). 
  • Scrolling DVM - see more numbers !
  • Inductance meter.
All with full schematics description and C source code.

Interrupt driven refresh

To drive the matrix properly you need to use a constant refresh rate that is independent of the executing code.

While it is possible to drive the display without interrupts as for the original led dot matrix project it is far better to use interrupts.

You can generate an interrupt at a pre-defined rate and refresh the display regularly without worrying too much what the code is doing in the mean time.  The only thing to watch is how long the interrupt routine itself is (it must be shorter than the interrupt rate).

Buffering

Buffering is a useful concept used in all the high end graphics cards - you can think of the led matrix as 64 pixels in a screen display - and as such the techniques for updating it are the same as used in computer games.  

Each led represents one pixel - in this case one color - whereas in complex computer graphics a pixel is represented by one or more bytes but the principle of using them is the same.

The scrolling display uses a buffer (an array) to store the led matrix data that is updated to the matrix at the screen refresh rate.

Project Update:

"Measuring Analogue Voltages

Without An ADC"

( FREE )

Warning: This project could be Removed at
any time and will NOT be available indefinitely.
To avoid disappointment get it Now.


Remember this is a project with full description and fully debugged C Source code - and it's not available from the main website.

You can only get it through this newsletter.

To get exclusive access enter your
Name and Primary email Now:
Primary Email
First Name

Don't worry -- your e-mail address is totally secure.
I promise to use it only to send you MicroZine
Note: Look through the back issues for your
No-ADC method).

P.S. The newsletter also has essential information for you as well.

More Resources...

Note: The screen must be updated at a rate faster than you eye notices which is why you have to update at about 50Hz (you can sometimes get away with 35Hz).  All graphics cards have to do this but instead of 8 bytes to update they have a whole screenfull which is why these graphics cards need a very fast graphics computing engine to do the job.

Using a buffer separates the interrupt refresh code from the code that updates the buffer.  This lets you optimize the interrupt code for fastest operation and ensures that the screen is constantly updated i.e. flicker free.  The rest of the program updates only the buffer itself whenever it likes and it does not need to be particularly fast

Note: For a true graphics system double buffering is used so that the display refresh data is taken from a buffer that is not being updated i.e. it makes the screen completely flicker free (the interrupt only uses data that is not half way through an update!)- this is only necessary for high end computer graphics systems and is not discussed in the projects.

Survey

I know your time is precious the survey only takes half a minute to do...


and as an extra thank you I'll take off 10% of the final price of the project set when you order (to do this just enter your email address when you complete the survey).

Extra led matrix projects survey
Please note that all fields followed by an asterisk must be filled in.
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Thanks again.

John.

Project Update:

"Measuring Analogue Voltages

Without An ADC"

( FREE )

Warning: This project could be Removed at
any time and will NOT be available indefinitely.
To avoid disappointment get it Now.


Remember this is a project with full description and fully debugged C Source code - and it's not available from the main website.

You can only get it through this newsletter.

To get exclusive access enter your
Name and Primary email Now:
Primary Email
First Name

Don't worry -- your e-mail address is totally secure.
I promise to use it only to send you MicroZine
Note: Look through the back issues for your
No-ADC method).

P.S. The newsletter also has essential information for you as well.

More Resources...

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