From e08330317fe9ad2545f5cda8e81726a48fe52df7 Mon Sep 17 00:00:00 2001
From: Vitor de Miranda Henrique <vitormhenrique@gmail.com>
Date: Fri, 12 May 2017 12:17:26 -0500
Subject: [PATCH] Create BME280.py

adding BME280 script
---
 octoprint_enclosure/BME280.py | 142 ++++++++++++++++++++++++++++++++++
 1 file changed, 142 insertions(+)
 create mode 100644 octoprint_enclosure/BME280.py

diff --git a/octoprint_enclosure/BME280.py b/octoprint_enclosure/BME280.py
new file mode 100644
index 0000000..9beba73
--- /dev/null
+++ b/octoprint_enclosure/BME280.py
@@ -0,0 +1,142 @@
+import smbus
+import sys
+import time
+from ctypes import c_short
+from ctypes import c_byte
+from ctypes import c_ubyte
+if len(sys.argv) == 2:
+DEVICE = int(sys.argv[1],16)
+else:
+print('-1 | -1')
+    sys.exit(1)
+bus = smbus.SMBus(1) # Rev 2 Pi, Pi 2 & Pi 3 uses bus 1
+# Rev 1 Pi uses bus 0
+def getShort(data, index):
+# return two bytes from data as a signed 16-bit value
+return c_short((data[index+1] << 8) + data[index]).value
+def getUShort(data, index):
+# return two bytes from data as an unsigned 16-bit value
+return (data[index+1] << 8) + data[index]
+def getChar(data,index):
+# return one byte from data as a signed char
+  result = data[index]
+if result > 127:
+    result -= 256
+return result
+def getUChar(data,index):
+# return one byte from data as an unsigned char
+  result =  data[index] & 0xFF
+return result
+def readBME280ID(addr=DEVICE):
+# Chip ID Register Address
+REG_ID     = 0xD0
+  (chip_id, chip_version) = bus.read_i2c_block_data(addr, REG_ID, 2)
+return (chip_id, chip_version)
+def readBME280All(addr=DEVICE):
+# Register Addresses
+REG_DATA = 0xF7
+REG_CONTROL = 0xF4
+REG_CONFIG  = 0xF5
+REG_CONTROL_HUM = 0xF2
+REG_HUM_MSB = 0xFD
+REG_HUM_LSB = 0xFE
+
+  # Oversample setting - page 27
+  OVERSAMPLE_TEMP = 2
+  OVERSAMPLE_PRES = 2
+  MODE = 1
+
+  # Oversample setting for humidity register - page 26
+  OVERSAMPLE_HUM = 2
+  bus.write_byte_data(addr, REG_CONTROL_HUM, OVERSAMPLE_HUM)
+
+  control = OVERSAMPLE_TEMP<<5 | OVERSAMPLE_PRES<<2 | MODE
+  bus.write_byte_data(addr, REG_CONTROL, control)
+
+  # Read blocks of calibration data from EEPROM
+  # See Page 22 data sheet
+  cal1 = bus.read_i2c_block_data(addr, 0x88, 24)
+  cal2 = bus.read_i2c_block_data(addr, 0xA1, 1)
+  cal3 = bus.read_i2c_block_data(addr, 0xE1, 7)
+
+  # Convert byte data to word values
+  dig_T1 = getUShort(cal1, 0)
+  dig_T2 = getShort(cal1, 2)
+  dig_T3 = getShort(cal1, 4)
+
+  dig_P1 = getUShort(cal1, 6)
+  dig_P2 = getShort(cal1, 8)
+  dig_P3 = getShort(cal1, 10)
+  dig_P4 = getShort(cal1, 12)
+  dig_P5 = getShort(cal1, 14)
+  dig_P6 = getShort(cal1, 16)
+  dig_P7 = getShort(cal1, 18)
+  dig_P8 = getShort(cal1, 20)
+  dig_P9 = getShort(cal1, 22)
+
+  dig_H1 = getUChar(cal2, 0)
+  dig_H2 = getShort(cal3, 0)
+  dig_H3 = getUChar(cal3, 2)
+
+  dig_H4 = getChar(cal3, 3)
+  dig_H4 = (dig_H4 << 24) >> 20
+  dig_H4 = dig_H4 | (getChar(cal3, 4) & 0x0F)
+
+  dig_H5 = getChar(cal3, 5)
+  dig_H5 = (dig_H5 << 24) >> 20
+  dig_H5 = dig_H5 | (getUChar(cal3, 4) >> 4 & 0x0F)
+
+  dig_H6 = getChar(cal3, 6)
+
+  # Wait in ms (Datasheet Appendix B: Measurement time and current calculation)
+  wait_time = 1.25 + (2.3 * OVERSAMPLE_TEMP) + ((2.3 * OVERSAMPLE_PRES) + 0.575) + ((2.3 * OVERSAMPLE_HUM)+0.575)
+  time.sleep(wait_time/1000)  # Wait the required time
+
+  # Read temperature/pressure/humidity
+  data = bus.read_i2c_block_data(addr, REG_DATA, 8)
+  pres_raw = (data[0] << 12) | (data[1] << 4) | (data[2] >> 4)
+  temp_raw = (data[3] << 12) | (data[4] << 4) | (data[5] >> 4)
+  hum_raw = (data[6] << 8) | data[7]
+
+  #Refine temperature
+  var1 = ((((temp_raw>>3)-(dig_T1<<1)))*(dig_T2)) >> 11
+  var2 = (((((temp_raw>>4) - (dig_T1)) * ((temp_raw>>4) - (dig_T1))) >> 12) * (dig_T3)) >> 14
+  t_fine = var1+var2
+  temperature = float(((t_fine * 5) + 128) >> 8);
+
+  # Refine pressure and adjust for temperature
+  var1 = t_fine / 2.0 - 64000.0
+  var2 = var1 * var1 * dig_P6 / 32768.0
+  var2 = var2 + var1 * dig_P5 * 2.0
+  var2 = var2 / 4.0 + dig_P4 * 65536.0
+  var1 = (dig_P3 * var1 * var1 / 524288.0 + dig_P2 * var1) / 524288.0
+  var1 = (1.0 + var1 / 32768.0) * dig_P1
+  if var1 == 0:
+    pressure=0
+  else:
+    pressure = 1048576.0 - pres_raw
+    pressure = ((pressure - var2 / 4096.0) * 6250.0) / var1
+    var1 = dig_P9 * pressure * pressure / 2147483648.0
+    var2 = pressure * dig_P8 / 32768.0
+    pressure = pressure + (var1 + var2 + dig_P7) / 16.0
+
+  # Refine humidity
+  humidity = t_fine - 76800.0
+  humidity = (hum_raw - (dig_H4 * 64.0 + dig_H5 / 16384.0 * humidity)) * (dig_H2 / 65536.0 * (1.0 + dig_H6 / 67108864.0 * humidity * (1.0 + dig_H3 / 67108864.0 * humidity)))
+  humidity = humidity * (1.0 - dig_H1 * humidity / 524288.0)
+  if humidity > 100:
+    humidity = 100
+  elif humidity < 0:
+    humidity = 0
+
+  return temperature/100.0,pressure/100.0,humidity
+
+def main():
+  try:
+    temperature,pressure,humidity = readBME280All()
+    print('{0:0.1f} | {1:0.1f}'.format(temperature, humidity))
+  except:
+     print('-1 | -1')
+
+if __name__=="__main__":
+   main()