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 Scanner speed - Big LEDs vs regular ones?
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By: Anonymous: Jeff () on Friday, May 18 2012 @ 01:54 AM PDT (Read 2224 times)  
Anonymous: Jeff

I just assembled two Larson Scanner kits, one with the big LEDs and one with the regular ones. They work great!

One question though...if I set them up so they're running the same speed and have the same jumper, one runs faster than the other. I would have expected that they would run at the same speed, and when one was in the middle of the LEDs, the other would be at one end, etc. Instead, they get in sync for a moment, with the lights bouncing together identically, then as one goes slightly faster, it gets ahead...and so on.

Note that they are not connected together, this is just two independent kits running sid-by-side.

Do the different LEDs make them run at slightly different speeds? Would a battery with a lower charge affect the speed?

I'm just curious.

Jeff





       
   
By: Windell (offline) on Saturday, May 19 2012 @ 11:41 PM PDT  
Windell

The microcontrollers in those kits run on their internal oscillators, each of which can vary by up to 10% or so. I believe that it is possible to use an ISP programmer to trim this somewhat via some calibration bytes, but I don't think that you'll be able to get true synchronization between two units without adding a precision reference or communication, e.g., synchronization pulses.


Windell H. Oskay
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