Code to interface the VCNL4000 to the Raspberry Pi

Adafruit_VCNL4000/Adafruit_I2C.py

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+#!/usr/bin/python
+
+import smbus
+
+# ===========================================================================
+# Adafruit_I2C Base Class
+# ===========================================================================
+
+class Adafruit_I2C :
+
+  def __init__(self, address, bus=smbus.SMBus(0), debug=False):
+    self.address = address
+    self.bus = bus
+    self.debug = debug
+
+  def reverseByteOrder(self, data):
+    "Reverses the byte order of an int (16-bit) or long (32-bit) value"
+    # Courtesy Vishal Sapre
+    dstr = hex(data)[2:].replace('L','')
+    byteCount = len(dstr[::2])
+    val = 0
+    for i, n in enumerate(range(byteCount)):
+      d = data & 0xFF
+      val |= (d << (8 * (byteCount - i - 1)))
+      data >>= 8
+    return val
+
+  def write8(self, reg, value):
+    "Writes an 8-bit value to the specified register/address"
+    try:
+      self.bus.write_byte_data(self.address, reg, value)
+      if (self.debug):
+        print("I2C: Wrote 0x%02X to register 0x%02X" % (value, reg))
+    except IOError, err:
+      print "Error accessing 0x%02X: Check your I2C address" % self.address
+      return -1
+
+  def writeList(self, reg, list):
+    "Writes an array of bytes using I2C format"
+    try:
+      self.bus.write_i2c_block_data(self.address, reg, list)
+    except IOError, err:
+      print "Error accessing 0x%02X: Check your I2C address" % self.address
+      return -1
+
+  def readU8(self, reg):
+    "Read an unsigned byte from the I2C device"
+    try:
+      result = self.bus.read_byte_data(self.address, reg)
+      if (self.debug):
+        print "I2C: Device 0x%02X returned 0x%02X from reg 0x%02X" % (self.address, result & 0xFF, reg)
+      return result
+    except IOError, err:
+      print "Error accessing 0x%02X: Check your I2C address" % self.address
+      return -1
+
+  def readS8(self, reg):
+    "Reads a signed byte from the I2C device"
+    try:
+      result = self.bus.read_byte_data(self.address, reg)
+      if (self.debug):
+        print "I2C: Device 0x%02X returned 0x%02X from reg 0x%02X" % (self.address, result & 0xFF, reg)
+      if (result > 127):
+        return result - 256
+      else:
+        return result
+    except IOError, err:
+      print "Error accessing 0x%02X: Check your I2C address" % self.address
+      return -1
+
+  def readU16(self, reg):
+    "Reads an unsigned 16-bit value from the I2C device"
+    try:
+      hibyte = self.bus.read_byte_data(self.address, reg)
+      result = (hibyte << 8) + self.bus.read_byte_data(self.address, reg+1)
+      if (self.debug):
+        print "I2C: Device 0x%02X returned 0x%04X from reg 0x%02X" % (self.address, result & 0xFFFF, reg)
+      return result
+    except IOError, err:
+      print "Error accessing 0x%02X: Check your I2C address" % self.address
+      return -1
+
+  def readS16(self, reg):
+    "Reads a signed 16-bit value from the I2C device"
+    try:
+      hibyte = self.bus.read_byte_data(self.address, reg)
+      if (hibyte > 127):
+        hibyte -= 256
+      result = (hibyte << 8) + self.bus.read_byte_data(self.address, reg+1)
+      if (self.debug):
+        print "I2C: Device 0x%02X returned 0x%04X from reg 0x%02X" % (self.address, result & 0xFFFF, reg)
+      return result
+    except IOError, err:
+      print "Error accessing 0x%02X: Check your I2C address" % self.address
+      return -1

Adafruit_VCNL4000/Adafruit_VCNL4000.py

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+#!/usr/bin/python
+
+import time
+from Adafruit_I2C import Adafruit_I2C
+
+# ===========================================================================
+# VCNL4000 Class
+# ===========================================================================
+
+# Address of the sensor
+VCNL4000_ADDRESS = 0x13
+
+# Commands
+VCNL4000_COMMAND = 0x80
+VCNL4000_PRODUCTID = 0x81
+VCNL4000_IRLED = 0x83
+VCNL4000_AMBIENTPARAMETER = 0x84
+VCNL4000_AMBIENTDATA = 0x85
+VCNL4000_PROXIMITYDATA = 0x87
+VCNL4000_SIGNALFREQ = 0x89
+VCNL4000_PROXINITYADJUST = 0x8A
+
+VCNL4000_3M125 = 0
+VCNL4000_1M5625 = 1
+VCNL4000_781K25 = 2
+VCNL4000_390K625 = 3
+
+VCNL4000_MEASUREAMBIENT = 0x10
+VCNL4000_MEASUREPROXIMITY = 0x08
+VCNL4000_AMBIENTREADY = 0x40
+VCNL4000_PROXIMITYREADY = 0x20
+
+class VCNL4000 :
+  i2c = None
+
+  # Constructor
+  def __init__(self, address=0x13):
+    self.i2c = Adafruit_I2C(address)
+
+    self.address = address
+
+    # Write proximity adjustement register
+    self.i2c.write8(VCNL4000_PROXINITYADJUST, 0x81);
+
+  # Read data from proximity sensor
+  def read_proximity(self):
+    self.i2c.write8(VCNL4000_COMMAND, VCNL4000_MEASUREPROXIMITY)
+    while True:
+      result = self.i2c.readU8(VCNL4000_COMMAND)
+      if (result and VCNL4000_PROXIMITYREADY):
+        return self.i2c.readU16(VCNL4000_PROXIMITYDATA)
+      time.sleep(0.001)
+
+

Adafruit_VCNL4000/Adafruit_VCNL4000_example.py

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+#!/usr/bin/python
+
+from Adafruit_VCNL4000 import VCNL4000
+import time
+
+# ===========================================================================
+# Example Code
+# ===========================================================================
+
+# Initialise the VNCL4000 sensor
+vcnl = VCNL4000(0x13)
+
+# Print proximity sensor data every 100 ms
+while True:
+
+	print "Data from proximity sensor", vcnl.read_proximity()
+	time.sleep(0.1)