rini:speed_log_notes
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rini:speed_log_notes [2009/04/17 05:05] ben |
rini:speed_log_notes [2009/04/17 06:49] ben |
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| * Planned platform is Arduino NANO with Serial LCD. | * Planned platform is Arduino NANO with Serial LCD. | ||
| - | * Arduino Mini is cheaper by %50 apparently... | + | * Arduino Mini is cheaper by %50 apparently... but requires additional USB connection- PICAXE USB cable may be suitable. |
| * Important is display type- black on white is best for sunlight conditions. Backlight also required. Maybe white on blue would work well in sunlight? | * Important is display type- black on white is best for sunlight conditions. Backlight also required. Maybe white on blue would work well in sunlight? | ||
| * Important is character support- LARGE NUMBERS are necessary. | * Important is character support- LARGE NUMBERS are necessary. | ||
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| * For now it seems that traveling 1 mile and counting the number of transducer clicks will provide an adequate average result | * For now it seems that traveling 1 mile and counting the number of transducer clicks will provide an adequate average result | ||
| * Once the number of clicks for 1 n. mile is found, math is Distance in n. mile divided by time in hours = Speed in knots, choose a very small unit of time to count clicks for to allow fast updates of speed calculation (2s?) | * Once the number of clicks for 1 n. mile is found, math is Distance in n. mile divided by time in hours = Speed in knots, choose a very small unit of time to count clicks for to allow fast updates of speed calculation (2s?) | ||
| - | <tab><blockquote> | ||
| - | Best I can get this described in ASCII: | ||
| + | Best I can get this described in ASCII: | ||
| + | <tab><blockquote> | ||
| D = distance in nautical miles | D = distance in nautical miles | ||
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| D = Y/X * 1 n.m. | D = Y/X * 1 n.m. | ||
| + | |||
| T = Z/3600 | T = Z/3600 | ||
| - | So: (Z/X * 1 n.m.) / (Z/3600) = Speed in knots for the sample period Z | + | So: (Y/X * 1 n.m.) / (Z/3600) = Speed in knots for the sample period Z |
| - | E.G. If we calibrate 1 n.m. at 2500 clicks (X=2500) and our sample/update period is 2 seconds (Z=2), and over that period we count 30 clicks (Y=30), then calculated speed would be (30/2500)/(2/3600) = S = 0.012 / 0.0011 = 1.0909 knots. | + | E.G. If we calibrate 1 n.m. at 2500 clicks (X=2500) and our sample/update period is 2 seconds (Z=2), and over that period we count 10 clicks (Y=10), then calculated speed would be (10/2500)/(2/3600) = S = 0.004 / 0.0006 = 6.67 knots. |
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| + | Hopefully we get faster turn rates that 5 rotations per second, otherwise it won't be very precise. | ||
| </blockquote> | </blockquote> | ||
| + | |||
rini/speed_log_notes.txt · Last modified: 2011/04/11 09:20 by ben
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