Home > Blog > DIY LedScreen from Worklamp and MSP430 - Part 2

DIY LedScreen from Worklamp and MSP430 - Part 2

Posted by admin on November 9, 2011


I've been updating the software of the DIY ledscreen, and started an endurance test! The screen with 40 leds you see in the video below has been running for  a week and 48 hours EDIT: Almost 3 MONTHS now, although only readable with lights off /EDIT, on 2 cheap double A batteries. If you are not into Electronics, programming or microcontrollers, just watch the video and skip the post below ;) Otherwise, I hope its somewhat helpful!

Also shown in the video, my homebuilt basic ascii set (32 till 126).
Each character consists of a varying number of Columns, each represented by a Hex value corresponding to lighted or dimmed leds in the column.
I have a vector containing the starting columns of the characters (offsets), and char length is calculated by taking the next offset minus the actual one. Works pretty fast, and with limited codesize.

Font is not final btw, the video is showing the very first test. I made an OpenOffice calc sheet where I could fill in ones and zeroes in a 5x5 grid (max char size), and reporting the Column Hex Value below. That way I at least had some visualisation of what I was doing. Capital font is looking pretty good I think (some small changes needed), but with the small font I was just experimenting, and it shows. 

The space between characters is also coded in, saving one column per char, which gives some more memory space.

For those not familiar with the MSP430 range, the chip used has 16KB flash and 512B of Ram, but i want to keep it as portable as possible, also to the lower ranges. And with me being used to developing 2d games within a framework, I had to change my coding methods quite drastically. It's still not pretty, and can be optimized A LOT still, but working on it :)
Main advantage of the MSP430 is that it's ultra low power. No low power modes actively used in this context yet, since it's currently using every cycle for drawing and updating, but once i move stuff to hardware pww and such, it might make a difference. But still, running for over a week ;)
Will post code, schematic and Calc sheet once everything is a bit more final!




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