Matrixing the Basic Stamp

Lab Rat

I have a bs2 and i was curious to see if anyone has a program for the stamp that runs the led matrix i have personaly tried it but i cant figure out how to get rid of the flicker can anyone help me

Mike Green

What LED matrix?

If it's a large matrix, it takes some time to do the multiplexing of the individual LEDs and eventually the flicker becomes visible. If you can speed up the program driving the matrix, you may reduce the flicker. Going to a faster Stamp model like a BS2sx or BS2px may be enough to reduce the flicker to where it's not visible.

Lab Rat

i dont exactly have funds enough to get a faster stamp
i like to work with what i have because i collect alot of free things
i am only making a 5 by 7 led matrix if you have a sample program for this it would be well appritiated

T&E Engineer

Here is one of the first BS2 LED Display signs I created from a ported PIC design and I later converted it into a faster SX28 design. It uses a 20x7 display but could easily be moved down to a 5x7 with less driver IC's (4017).

http://forums.parallax.com/showthread.php?p=561144

Lab Rat

i have found some resources for using an 8 bit shift register instead of the decade counter i think if it turns out right i can modify pre-existing programs that are demonstrated in the stamp works manual.
me being the fool i am i now have 70 LEDs oriented in the wrong polarity for the IC that i am using so i now have to put in 7 NPN transistors to get things back on track. i figured out that i screwed up when i was sitting in study hall and trying to figure out how to program it. since i was not about to dig out a soldering iron in the middle of studyhall i decided to try out the 74LS164 (8 bit shift register) that i was using. for those who ask where i pull parts from at school i have a few necessary parts and what not in a box with me that i carry from home to school it is my graduation project. well any how i set up the 74LS164 on my homework board plugged in a few LEDs and amused a few freshmen (how stupid they are) (REMEMBER i am only a senior in high school not trying to offend college freshmen) i must admit i amused myself too lol

Lab Rat

i would like to quote one of my above posts.
it started out as 5/7 but i had enough extra LEDs so i doubled the size to 7/10 so it is bigger and better(translated: harder to program)