146 lines
3.5 KiB
Python
Executable File
146 lines
3.5 KiB
Python
Executable File
#!/usr/bin/python
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#--------------------------------------
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#
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# bmp180.py
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# Read data from a digital pressure sensor.
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# And broadcast to network.
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# Author : Jony Silva
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# Date : Wed 12 Jul 21:03:26 UTC 2017
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#
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# Reading the chip code taken from :
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# http://www.raspberrypi-spy.co.uk/
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#
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#--------------------------------------
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import smbus
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import time
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from socket import *
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from ctypes import c_short
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DEVICE = 0x77 # Default device I2C address
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# addressing information of target
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IPADDR = '<broadcast>'
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PORTNUM = 10000
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#bus = smbus.SMBus(0) # Rev 1 Pi uses 0
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bus = smbus.SMBus(1) # Rev 2 Pi uses 1
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def convertToString(data):
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# Simple function to convert binary data into
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# a string
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return str((data[1] + (256 * data[0])) / 1.2)
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def getShort(data, index):
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# return two bytes from data as a signed 16-bit value
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return c_short((data[index] << 8) + data[index + 1]).value
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def getUshort(data, index):
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# return two bytes from data as an unsigned 16-bit value
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return (data[index] << 8) + data[index + 1]
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def readBmp180Id(addr=DEVICE):
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# Chip ID Register Address
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REG_ID = 0xD0
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(chip_id, chip_version) = bus.read_i2c_block_data(addr, REG_ID, 2)
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return (chip_id, chip_version)
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def readBmp180(addr=DEVICE):
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# Register Addresses
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REG_CALIB = 0xAA
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REG_MEAS = 0xF4
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REG_MSB = 0xF6
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REG_LSB = 0xF7
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# Control Register Address
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CRV_TEMP = 0x2E
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CRV_PRES = 0x34
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# Oversample setting
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OVERSAMPLE = 3 # 0 - 3
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# Read calibration data
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# Read calibration data from EEPROM
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cal = bus.read_i2c_block_data(addr, REG_CALIB, 22)
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# Convert byte data to word values
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AC1 = getShort(cal, 0)
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AC2 = getShort(cal, 2)
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AC3 = getShort(cal, 4)
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AC4 = getUshort(cal, 6)
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AC5 = getUshort(cal, 8)
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AC6 = getUshort(cal, 10)
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B1 = getShort(cal, 12)
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B2 = getShort(cal, 14)
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MB = getShort(cal, 16)
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MC = getShort(cal, 18)
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MD = getShort(cal, 20)
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# Read temperature
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bus.write_byte_data(addr, REG_MEAS, CRV_TEMP)
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time.sleep(0.005)
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(msb, lsb) = bus.read_i2c_block_data(addr, REG_MSB, 2)
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UT = (msb << 8) + lsb
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# Read pressure
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bus.write_byte_data(addr, REG_MEAS, CRV_PRES + (OVERSAMPLE << 6))
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time.sleep(0.04)
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(msb, lsb, xsb) = bus.read_i2c_block_data(addr, REG_MSB, 3)
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UP = ((msb << 16) + (lsb << 8) + xsb) >> (8 - OVERSAMPLE)
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# Refine temperature
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X1 = ((UT - AC6) * AC5) >> 15
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X2 = (MC << 11) / (X1 + MD)
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B5 = X1 + X2
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temperature = int(B5 + 8) >> 4
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# Refine pressure
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B6 = B5 - 4000
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B62 = int(B6 * B6) >> 12
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X1 = (B2 * B62) >> 11
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X2 = int(AC2 * B6) >> 11
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X3 = X1 + X2
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B3 = (((AC1 * 4 + X3) << OVERSAMPLE) + 2) >> 2
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X1 = int(AC3 * B6) >> 13
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X2 = (B1 * B62) >> 16
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X3 = ((X1 + X2) + 2) >> 2
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B4 = (AC4 * (X3 + 32768)) >> 15
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B7 = (UP - B3) * (50000 >> OVERSAMPLE)
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P = (B7 * 2) / B4
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X1 = (int(P) >> 8) * (int(P) >> 8)
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X1 = (X1 * 3038) >> 16
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X2 = int(-7357 * P) >> 16
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pressure = int(P + ((X1 + X2 + 3791) >> 4))
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return (temperature/10.0,pressure/100.0)
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def main():
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(chip_id, chip_version) = readBmp180Id()
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print("Chip ID : {0}".format(chip_id))
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print("Version : {0}".format(chip_version))
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print
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(temperature,pressure) = readBmp180()
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temp = "Temperature : {0} C".format(temperature)
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press = "Pressure : {0} mbar".format(pressure)
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print temp
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print press
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# initialize a socket, think of it as a cable
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# SOCK_DGRAM specifies that this is UDP
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s = socket(AF_INET, SOCK_DGRAM)
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s.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
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s.setsockopt(SOL_SOCKET, SO_BROADCAST, 1)
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s.sendto(temp, (IPADDR, PORTNUM))
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# close the socket
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s.close()
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if __name__=="__main__":
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main()
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