From: Steven Baltakatei Sandoval Date: Sat, 11 Jul 2020 08:42:46 +0000 (+0000) Subject: feat(pressure):Add python script for outputting pressure to stdout X-Git-Url: https://zdv2.bktei.com/gitweb/EVA-2020-02.git/commitdiff_plain/b6f22edba271c384d99d18ab86420a74e549e7e0 feat(pressure):Add python script for outputting pressure to stdout --- diff --git a/doc/pressure/README.org b/doc/pressure/README.org new file mode 100644 index 0000000..3852ac4 --- /dev/null +++ b/doc/pressure/README.org @@ -0,0 +1,43 @@ +* Software +** BMP388 Pressure sensor +The following command will download a repository containing a python +script that can pull pressure data from the BerryGPS-IMU v3.5's BMP388 +: git clone https://github.com/getelectronics/PIBits.git +*** 2020-04-10 Note regarding getting data from BMP388 (task:8a5607fe) +2020-04-10T03:03Z; baltakatei> + +- I ordered another two Raspberry Pi Zero W's and another BerryIMU-GPS. + +- I think I found the problem with the pressure sensor. According to a + 2020-03-12 post by johnmark at + https://ozzmaker.com/forums/topic/temp-barometer/ , the BerryIMU-GPS + version 3.5 uses BMP388, not BMP280. johnmark posted a link to a + python script that works for the BMP388 pressure sensor at: + + https://github.com/getelectronics/PIBits/blob/master/python/bmp388.py + +- I have downloaded this PIBits git repository to jalrasaroa-02 and am + testing it now. It works. + +- I am checking to see how I can automatically update the clock on + jalrasaora-02 via a network time server. Reading instructions at + https://www.garron.me/en/go2linux/how-to-set-date-and-time-linux.html + . + +- I am installing the `ntp` package described here: + + https://www.digitalocean.com/community/tutorials/how-to-set-up-time-synchronization-on-debian-10 + + $ sudo apt-get update && sudo apt-get upgrade -y && sudo apt-get install ntp + + - I confirmed that the ntp time synchronization service is running with: + + sudo systemctl status ntp + +- I am creating a git repository to store executables and setup + instructions for Raspberry Pi Zero W's used for logging: + + - Location (GPS WGS84) + - Air pressure (Pa) + - Temperature (°C) + - Direction (magnetic north heading) diff --git a/exec/pressure/bmp388.py b/exec/pressure/bmp388.py new file mode 100644 index 0000000..b396b59 --- /dev/null +++ b/exec/pressure/bmp388.py @@ -0,0 +1,217 @@ +#!/usr/bin/python +# -*- coding: utf-8 -*- +import time +import smbus +import math + +# define BMP388 Device I2C address + +I2C_ADD_BMP388_AD0_LOW = 0x76 +I2C_ADD_BMP388_AD0_HIGH = 0x77 +I2C_ADD_BMP388 = I2C_ADD_BMP388_AD0_HIGH + +BMP388_REG_ADD_WIA = 0x00 +BMP388_REG_VAL_WIA = 0x50 + +BMP388_REG_ADD_ERR = 0x02 +BMP388_REG_VAL_FATAL_ERR = 0x01 +BMP388_REG_VAL_CMD_ERR = 0x02 +BMP388_REG_VAL_CONF_ERR = 0x04 + +BMP388_REG_ADD_STATUS = 0x03 +BMP388_REG_VAL_CMD_RDY = 0x10 +BMP388_REG_VAL_DRDY_PRESS = 0x20 +BMP388_REG_VAL_DRDY_TEMP = 0x40 + +BMP388_REG_ADD_CMD = 0x7E +BMP388_REG_VAL_EXTMODE_EN = 0x34 +BMP388_REG_VAL_FIFI_FLUSH = 0xB0 +BMP388_REG_VAL_SOFT_RESET = 0xB6 + +BMP388_REG_ADD_PWR_CTRL = 0x1B +BMP388_REG_VAL_PRESS_EN = 0x01 +BMP388_REG_VAL_TEMP_EN = 0x02 +BMP388_REG_VAL_NORMAL_MODE = 0x30 + +BMP388_REG_ADD_PRESS_XLSB = 0x04 +BMP388_REG_ADD_PRESS_LSB = 0x05 +BMP388_REG_ADD_PRESS_MSB = 0x06 +BMP388_REG_ADD_TEMP_XLSB = 0x07 +BMP388_REG_ADD_TEMP_LSB = 0x08 +BMP388_REG_ADD_TEMP_MSB = 0x09 + +BMP388_REG_ADD_T1_LSB = 0x31 +BMP388_REG_ADD_T1_MSB = 0x32 +BMP388_REG_ADD_T2_LSB = 0x33 +BMP388_REG_ADD_T2_MSB = 0x34 +BMP388_REG_ADD_T3 = 0x35 +BMP388_REG_ADD_P1_LSB = 0x36 +BMP388_REG_ADD_P1_MSB = 0x37 +BMP388_REG_ADD_P2_LSB = 0x38 +BMP388_REG_ADD_P2_MSB = 0x39 +BMP388_REG_ADD_P3 = 0x3A +BMP388_REG_ADD_P4 = 0x3B +BMP388_REG_ADD_P5_LSB = 0x3C +BMP388_REG_ADD_P5_MSB = 0x3D +BMP388_REG_ADD_P6_LSB = 0x3E +BMP388_REG_ADD_P6_MSB = 0x3F +BMP388_REG_ADD_P7 = 0x40 +BMP388_REG_ADD_P8 = 0x41 +BMP388_REG_ADD_P9_LSB = 0x42 +BMP388_REG_ADD_P9_MSB = 0x43 +BMP388_REG_ADD_P10 = 0x44 +BMP388_REG_ADD_P11 = 0x45 + + +class BMP388(object): + + """docstring for BMP388""" + + def __init__(self, address=I2C_ADD_BMP388): + self._address = address + self._bus = smbus.SMBus(0x01) + + # Load calibration values. + + if self._read_byte(BMP388_REG_ADD_WIA) == BMP388_REG_VAL_WIA: + print("Pressure sersor is BMP388!\r\n") + u8RegData = self._read_byte(BMP388_REG_ADD_STATUS) + if u8RegData & BMP388_REG_VAL_CMD_RDY: + self._write_byte(BMP388_REG_ADD_CMD, + BMP388_REG_VAL_SOFT_RESET) + time.sleep(0.01) + else: + print ("Pressure sersor NULL!\r\n") + self._write_byte(BMP388_REG_ADD_PWR_CTRL, + BMP388_REG_VAL_PRESS_EN + | BMP388_REG_VAL_TEMP_EN + | BMP388_REG_VAL_NORMAL_MODE) + self._load_calibration() + + def _read_byte(self, cmd): + return self._bus.read_byte_data(self._address, cmd) + + def _read_s8(self, cmd): + result = self._read_byte(cmd) + if result > 128: + result -= 256 + return result + + def _read_u16(self, cmd): + LSB = self._bus.read_byte_data(self._address, cmd) + MSB = self._bus.read_byte_data(self._address, cmd + 0x01) + return (MSB << 0x08) + LSB + + def _read_s16(self, cmd): + result = self._read_u16(cmd) + if result > 32767: + result -= 65536 + return result + + def _write_byte(self, cmd, val): + self._bus.write_byte_data(self._address, cmd, val) + + def _load_calibration(self): + print ("_load_calibration\r\n") + self.T1 = self._read_u16(BMP388_REG_ADD_T1_LSB) + self.T2 = self._read_u16(BMP388_REG_ADD_T2_LSB) + self.T3 = self._read_s8(BMP388_REG_ADD_T3) + self.P1 = self._read_s16(BMP388_REG_ADD_P1_LSB) + self.P2 = self._read_s16(BMP388_REG_ADD_P2_LSB) + self.P3 = self._read_s8(BMP388_REG_ADD_P3) + self.P4 = self._read_s8(BMP388_REG_ADD_P4) + self.P5 = self._read_u16(BMP388_REG_ADD_P5_LSB) + self.P6 = self._read_u16(BMP388_REG_ADD_P6_LSB) + self.P7 = self._read_s8(BMP388_REG_ADD_P7) + self.P8 = self._read_s8(BMP388_REG_ADD_P8) + self.P9 = self._read_s16(BMP388_REG_ADD_P9_LSB) + self.P10 = self._read_s8(BMP388_REG_ADD_P10) + self.P11 = self._read_s8(BMP388_REG_ADD_P11) + + # print(self.T1) + # print(self.T2) + # print(self.T3) + # print(self.P1) + # print(self.P2) + # print(self.P3) + # print(self.P4) + # print(self.P5) + # print(self.P6) + # print(self.P7) + # print(self.P8) + # print(self.P9) + # print(self.P10) + # print(self.P11) + + def compensate_temperature(self, adc_T): + partial_data1 = adc_T - 256 * self.T1 + partial_data2 = self.T2 * partial_data1 + partial_data3 = partial_data1 * partial_data1 + partial_data4 = partial_data3 * self.T3 + partial_data5 = partial_data2 * 262144 + partial_data4 + partial_data6 = partial_data5 / 4294967296 + self.T_fine = partial_data6 + comp_temp = partial_data6 * 25 / 16384 + return comp_temp + + def compensate_pressure(self, adc_P): + partial_data1 = self.T_fine * self.T_fine + partial_data2 = partial_data1 / 0x40 + partial_data3 = partial_data2 * self.T_fine / 256 + partial_data4 = self.P8 * partial_data3 / 0x20 + partial_data5 = self.P7 * partial_data1 * 0x10 + partial_data6 = self.P6 * self.T_fine * 4194304 + offset = self.P5 * 140737488355328 + partial_data4 \ + + partial_data5 + partial_data6 + + partial_data2 = self.P4 * partial_data3 / 0x20 + partial_data4 = self.P3 * partial_data1 * 0x04 + partial_data5 = (self.P2 - 16384) * self.T_fine * 2097152 + sensitivity = (self.P1 - 16384) * 70368744177664 \ + + partial_data2 + partial_data4 + partial_data5 + + partial_data1 = sensitivity / 16777216 * adc_P + partial_data2 = self.P10 * self.T_fine + partial_data3 = partial_data2 + 65536 * self.P9 + partial_data4 = partial_data3 * adc_P / 8192 + partial_data5 = partial_data4 * adc_P / 512 + partial_data6 = adc_P * adc_P + partial_data2 = self.P11 * partial_data6 / 65536 + partial_data3 = partial_data2 * adc_P / 128 + partial_data4 = offset / 0x04 + partial_data1 + partial_data5 \ + + partial_data3 + comp_press = partial_data4 * 25 / 1099511627776 + return comp_press + + def get_temperature_and_pressure_and_altitude(self): + """Returns pressure in Pa as double. Output value of "6386.2"equals 96386.2 Pa = 963.862 hPa.""" + + xlsb = self._read_byte(BMP388_REG_ADD_TEMP_XLSB) + lsb = self._read_byte(BMP388_REG_ADD_TEMP_LSB) + msb = self._read_byte(BMP388_REG_ADD_TEMP_MSB) + adc_T = (msb << 0x10) + (lsb << 0x08) + xlsb + temperature = self.compensate_temperature(adc_T) + xlsb = self._read_byte(BMP388_REG_ADD_PRESS_XLSB) + lsb = self._read_byte(BMP388_REG_ADD_PRESS_LSB) + msb = self._read_byte(BMP388_REG_ADD_PRESS_MSB) + + adc_P = (msb << 0x10) + (lsb << 0x08) + xlsb + pressure = self.compensate_pressure(adc_P) + altitude = 4433000 * (0x01 - pow(pressure / 100.0 / 101325.0, + 0.1903)) + + return (temperature, pressure, altitude) + + +if __name__ == '__main__': + + import time + + print("BMP388 Test Program ...\n") + + bmp388 = BMP388() + + while True: + time.sleep(0.5) + temperature,pressure,altitude = bmp388.get_temperature_and_pressure_and_altitude() + print(' Temperature = %.1f Pressure = %.2f Altitude =%.2f '%(temperature/100.0,pressure/100.0,altitude/100.0))