Micro-wizard or champ?

Vitamin K said:
The specs on the page assume that you're using the Arduino Uno, which has a clock frequency of 16Mhz. If you used the same schematic (adjusted for voltage) and code, but substituted something like the Arduino Due, which has a frequency of 84 MHz, would this presumably yield a better resolution, or would you be limited by other factors?
While you are correct that the faster (84 MHz and a ton of I/O - that think is a beast !!) processor could execute code proportionally faster, there is always a slowest element somewhere. I can't really answer without getting into the hardware and software much more than I have time for. You might also have to write your own code in order to optimize for speed since the available code is probably written fairly generically and flexibly. It would be interesting to find out though.
 
Hi Y'all

I have a friend who hosts a few PWD races every year who raised the 5 decimal point display question. He complains that too many times they see ties like 2.1234 and 2.1234 seconds. So they have to put in extra lengths of lanes in the horizontal run and rerun the tied cars to determine the winner. They would like to show the attending viewers a display like 2.12342 and 2.12344 to make the possibility of ties 10 times less likely.

Stuart of Micro Wizard confirms what I am hearing here, that the computers are able to store elapsed time data down to like 2.12345 seconds but there are no displays which can show this, only 2.1234 type displays.

Regards

Doc Jobe
 
If they are seeing ties more than once to the 10,000th of a second, that sounds more like a software issue, or their hardware can't provide accuracy to the 10,000th.

I have a vague memory of there having been an issue here (at the NPWDRL) in which the final digit was not actually changing, and was *always* 4 (or something). The fix lied in the software settings. Sorry that I don't have anything more than that vague memory. Or maybe it was on my church's/troop's track...
 
Vitamin K said:
The Arduino-based timer build here stores the finish time in microseconds. However, since there's got to be some kind of time lag in terms of the amount of time it takes to update the loop that's reading the status of the finish line phototransistors, I don't know what the actual resolution is in "real world" terms.

I'm going by memory here, but I believe the designer of that timer told me that on a two lane track he was seeing something like 40 microseconds (.000040) for the main loop and 12 microseconds (.000012) for the finish loop.
 
What is the probably of having identical times in a two car race or two runs with a single car?

I figure the probability of such a two car time coincidence to be approximated by
Y = 0.2685 * X^0.986
where Y is the probability and X is the ratio <time quantization> / <standard deviation>
and X < 200%.

For example, assuming a finish time standard deviation of 7 milliseconds and a timer increment of 1 millisecond, then:
X = <timer increment>/<standard deviation> = 0.001/0.007 = 14.29%
Filling this X value into Y = 0.2685 * X^0.986 gives Y = 3.94%.
Thus I expect that about 4% of the two-car runs should be a tie.
Using a time with 10 microsecond resolution would give about ties about 0.41% of the time.
Is that about what you all see in practice?
 
I just ordered a 4-lane Best Track and asked for it to be drilled for the Micro Wizard timer. I also opted for the split gate and lift kit. My question is, will the k3 grand prix package work with the Best Track, and if so, do I want it? Should I be looking at another start option? Any other advice?

http://www.microwizard.com/gppage.html
 
The only problem with the laser start is that the first car to break the beam starts the times..... With a switch, the times are started by the gate, not the cars....
 
Hi Y'all

I have a friend who hosts a few PWD races every year who raised the 5 decimal point display question. He complains that too many times they see ties like 2.1234 and 2.1234 seconds. So they have to put in extra lengths of lanes in the horizontal run and rerun the tied cars to determine the winner. They would like to show the attending viewers a display like 2.12342 and 2.12344 to make the possibility of ties 10 times less likely.

Stuart of Micro Wizard confirms what I am hearing here, that the computers are able to store elapsed time data down to like 2.12345 seconds but there are no displays which can show this, only 2.1234 type displays.

Regards

Doc Jobe

I find this plague of ties that your friend complains of to be incredibly unlikely. Especially given the probability that these are not "pro" built cars, the margin of victory to be under .0001 seconds frequently enough to be considered a problem becomes even less credible.
I call shenanigans.
I heard a story once that USA astronauts found that a pen does not work in space due to the lack of gravity. They spent a great deal of time and money researching a way to solve this...and they did! They invented a space pen that works. Russian cosmonauts also discovered the pen problem....so they used a pencil.
Be a cosmonaut. Re-run the race.
 
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Always remember that resolution (number of digits displayed) doesn't guarantee actual accuracy or precision.