kopia lustrzana https://github.com/GuyCarver/MicroPython
83 wiersze
2.4 KiB
Python
83 wiersze
2.4 KiB
Python
##
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# Ultrasonic library for MicroPython's pyboard.
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# Compatible with HC-SR04 and SRF04.
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#
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# Copyright 2014 - Sergio Conde Gómez <skgsergio@gmail.com>
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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##
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import pyb
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# Pin configuration.
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# WARNING: Do not use PA4-X5 or PA5-X6 as the echo pin without a 1k resistor.
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def wait( aCount ):
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j = 0;
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for i in range(aCount):
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j += i
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class Ultrasonic:
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def __init__(self, tPin, ePin):
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self.triggerPin = tPin
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self.echoPin = ePin
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# Init trigger pin (out)
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self.trigger = pyb.Pin(self.triggerPin)
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self.trigger.init(pyb.Pin.OUT_PP, pyb.Pin.PULL_NONE)
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self.trigger.low()
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# Init echo pin (in)
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self.echo = pyb.Pin(self.echoPin)
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self.echo.init(pyb.Pin.IN, pyb.Pin.PULL_NONE)
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def distance_in_inches(self):
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return (self.distance_in_cm() * 0.3937)
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def distance_in_cm(self):
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start = 0
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end = 0
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# Create a microseconds counter.
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micros = pyb.Timer(2, prescaler=83, period=0x3fffffff)
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micros.counter(0)
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# Send a 10us pulse.
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self.trigger.high()
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pyb.udelay(10)
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self.trigger.low()
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# Wait 'till whe pulse starts.
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while self.echo.value() == 0:
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start = micros.counter()
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j = 0
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# Wait 'till the pulse is gone.
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while self.echo.value() == 1 and j < 1000:
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# print("wait end")
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# wait(1000)
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j += 1
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end = micros.counter()
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# Deinit the microseconds counter
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micros.deinit()
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# Calc the duration of the recieved pulse, divide the result by
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# 2 (round-trip) and divide it by 29 (the speed of sound is
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# 340 m/s and that is 29 us/cm).
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dist_in_cm = ((end - start) / 2) / 29
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return dist_in_cm
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