def distance(self, distance_unit=CM):
"""
Measure distance to closest object.
:param distance_unit: The units to measure the distance in. Optional, default Srf08.CM.
:type distance_unit: Srf08.CM, Srf08.INCH or Srf08.MS.
:return: The distance in specified units.
:rtype: int
:raise: IoTPy_ThingError
"""
if distance_unit not in (Srf08.CM, Srf08.INCH, Srf08.MS):
errmsg("Wrong units for distance, should be 'c' or 'i' or 'm'.")
raise IoTPy_ThingError(
"Wrong units for distance, should be 'c' or 'i' or 'm'.")
try:
self.interface.transaction(self.address, Srf08.CMD + distance_unit,
0)
sleep(0.08)
distance = unpack(
'>H',
self.interface.transaction(self.address, Srf08.RESULT,
2)[:2])[0]
except IoTPy_ThingError:
raise IoTPy_ThingError("srf08 - distance reading error.")
return distance
def _read_raw(self, command, regaddr, regcount):
self.interface.transaction(self.address, '\0', 0)
self.interface.transaction(self.address,
command + regaddr + chr(regcount), 0)
sleep(0.002)
buf, err = self.interface.transaction(self.address, '', regcount + 4)
if err:
raise IoTPy_ThingError("AM2321 reading error.")
crc = unpack('<H', buf[-2:])[0]
if crc != self._am_crc16(buf[:-2]):
raise IoTPy_ThingError("AM2321 CRC error.")
return buf[2:-2]
def distance(self, distance_unit=CM):
if distance_unit not in (Srf08.CM, Srf08.INCH, Srf08.MS):
errmsg("Wrong units for distance, should be 'c' or 'i' or 'm'.")
raise IoTPy_ThingError(
"Wrong units for distance, should be 'c' or 'i' or 'm'.")
try:
self.interface.transaction(self.address, Srf08.CMD + distance_unit,
0)
sleep(0.08)
distance = unpack(
'>H',
self.interface.transaction(self.address, Srf08.RESULT,
2)[:2])[0]
except IoTPy_ThingError:
raise IoTPy_ThingError("srf08 - distance reading error.")
return distance
def transaction(self, address, write_data, read_length, ignore_error=False):
"""
Perform I2C data transaction.
I2C data transaction consists of (optional) write transaction, followed by (optional) read transaction.
:param address: I2C device address.
:type address: int
:param write_data: A byte sequence to be transmitted. If write_data is None, no write transaction will be executed.
:type write_data: str
:param read_length: A number of bytes to be received. If read_length is 0, no read trasaction will be executed.
:type read_length: int
:param ignore_error:
:type ignore_error: bool
:return: Received data or I2C communication error code.
:rtype: str or int
:raise: IoTPy_APIError, IoTPy_ThingError
"""
try:
result = self.board.decode_sfp(self.board.uper_io(1, self.board.encode_sfp(41, [address, write_data, read_length])))
except IoTPy_APIError:
errmsg("UPER API: I2C bus not connected.")
raise IoTPy_IOError("I2C bus not connected.")
if type(result[1][0]) == IntType and not ignore_error:
errmsg("UPER Interface: I2C device with address %#x returned error code %#x.", address, result[1][0])
raise IoTPy_ThingError("I2C slave reading error.")
else:
return result[1][0]
def humidity(self):
try:
self.interface.transaction(Si7020.ADDRESS, Si7020.RH_HOLD, 0)
result_raw = self.interface.transaction(Si7020.ADDRESS, '', 2)
result_integer = unpack('>H', result_raw[:2])[0]
rh = (125.0 * result_integer) / 65536 - 6
except IoTPy_ThingError:
raise IoTPy_ThingError("Si7020 - humidity reading error.")
return rh
def temperature(self):
try:
self.interface.transaction(Si7020.ADDRESS, Si7020.TEMP_HOLD, 0)
result_raw = self.interface.transaction(Si7020.ADDRESS, '', 2)
result_integer = unpack('>H', result_raw[:2])[0]
temp = (175.72 * result_integer) / 65536 - 46.85
except IoTPy_ThingError:
raise IoTPy_ThingError("Si7020 - temperature reading error.")
return temp
def transaction(self, address, write_data, read_length, ignore_error=False):
try:
result = self.board.decode_sfp(self.board.uper_io(1, self.board.encode_sfp(41, [address, write_data, read_length])))
except IoTPy_APIError:
errmsg("UPER API: I2C bus not connected.")
raise IoTPy_IOError("I2C bus not connected.")
if type(result[1][0]) == IntType and not ignore_error:
errmsg("UPER Interface: I2C device with address %#x returned error code %#x.", address, result[1][0] )
raise IoTPy_ThingError("I2C slave reading error.")
else:
return result[1][0]
def light(self):
try:
self.interface.transaction(self.address, Srf08.CMD + Srf08.CM, 0)
sleep(0.08)
light = unpack(
'>B',
self.interface.transaction(self.address, Srf08.LIGHT,
1)[:1])[0]
except IoTPy_ThingError:
raise IoTPy_ThingError("srf08 - distance reading error.")
return light
def temperature(self):
"""
Read and return temperature.
:return: Temperature in celsius.
:rtype: int
:raise: IoTPy_ThingError
"""
try:
result_raw = self.interface.transaction(self.address, '\x00', 2)
result_integer = unpack('>H', result_raw)[0]
temperature = result_integer / 256.0
except IoTPy_ThingError:
raise IoTPy_ThingError("LM75 - temperature reading error.")
return temperature
def analog(self):
"""
Read, convert and return analog sensor value.
:return: Analog ADC value
:rtype: int
:raise: IoTPy_ThingError
"""
try:
result_raw = self.interface.transaction(self.address,
SI70xx_CMD_ANALOG, 2)
result_integer = unpack('>H', result_raw[:2])[0]
return result_integer
except IoTPy_ThingError:
raise IoTPy_ThingError("Si7020 - analog reading error.")
def humidity(self):
"""
Read, convert and return humidity.
:return: Humidity value in percent.
:rtype: float
:raise: IoTPy_ThingError
"""
try:
result_raw = self.interface.transaction(self.address,
SI70xx_CMD_RH_HOLD, 2)
result_integer = unpack('>H', result_raw[:2])[0]
rh = (125.0 * result_integer) / 65536 - 6
except IoTPy_ThingError:
raise IoTPy_ThingError("Si7020 - humidity reading error.")
return rh
def temperature(self):
"""
Read, convert and return temperature.
:return: Temperature value in celsius.
:rtype: float
:raise: IoTPy_ThingError
"""
try:
result_raw = self.interface.transaction(self.address,
SI70xx_CMD_TEMP_HOLD, 2)
result_integer = unpack('>H', result_raw[:2])[0]
temp = (175.72 * result_integer) / 65536 - 46.85
except IoTPy_ThingError:
raise IoTPy_ThingError("Si7020 - temperature reading error.")
return temp
def light(self):
"""
Measure light intensity.
:return: Light intensity in relative units.
:rtype: int
:raise: IoTPy_ThingError
"""
try:
self.interface.transaction(self.address, Srf08.CMD + Srf08.CM, 0)
sleep(0.08)
light = unpack(
'>B',
self.interface.transaction(self.address, Srf08.LIGHT,
1)[:1])[0]
except IoTPy_ThingError:
raise IoTPy_ThingError("srf08 - distance reading error.")
return light