NAME

Device::Temperature::TMP102 - I2C interface to TMP102 temperature sensor using Device::SMBus

SYNOPSIS

use Device::Temperature::TMP102;

my $device = shift @ARGV || '/dev/i2c-1';

my $dev = Device::Temperature::TMP102->new( I2CBusDevicePath => $device );

my $temp = $dev->getTemp();

print "Temp:\n";
printf ( "\t%2.2f C\n", $temp );
printf ( "\t%2.2f F\n", $temp * 1.8 + 32 );

DESCRIPTION

Read temperature for a TMP102 temperature sensor over I2C.

This library correctly handles temperatures below freezing (0 degrees Celsius).

TROUBLESHOOTING

Check for your device on i2cbus 1 using the i2cdetect command, e.g.:

$ i2cdetect -y 1

     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- 48 -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

This indicates my TMP102 chip address is 0x48 on i2cbus 1.

Use the command-line tool i2cget to try to get a 12-bit reading from the device, e.g.:

$ i2cget -y 1 0x48 0x00 w
0x2003

Refer to the documentation on Device::SMBus for information on enabling the i2c driver.

I also found this page to be helpful:

http://donalmorrissey.blogspot.co.uk/2012/09/raspberry-pi-i2c-tutorial.html

In the process of testing this on raspberry pi, I saw this error:

perl: symbol lookup error: .../Device/SMBus/SMBus.so: undefined symbol: i2c_smbus_write_byte

The fix was to install the package libi2c-dev.

SEE ALSO

https://www.sparkfun.com/products/11931

https://www.sparkfun.com/datasheets/Sensors/Temperature/tmp102.pdf

http://donalmorrissey.blogspot.com/2012/09/raspberry-pi-i2c-tutorial.html

https://github.com/sparkfun/Digital_Temperature_Sensor_Breakout_-_TMP102

SOURCE

With code and comments taken from example code for the ATmega328:

http://www.sparkfun.com/datasheets/Sensors/Temperature/tmp102.zip

/*
  TMP Test Code
  5-31-10
  Copyright Spark Fun Electronics© 2010
  Nathan Seidle

  Example code for the TMP102 11-bit I2C temperature sensor

  You will need to connect the ADR0 pin to one of four places. This
  code assumes ADR0 is tied to VCC.  This results in an I2C address
  of 0x93 for read, and 0x92 for write.

  This code assumes regular 12 bit readings. If you want the
  extended mode for higher temperatures, the code will have to be
  modified slightly.

*/

VERSION

ATTRIBUTES

I2CDeviceAddress

Contains the I2CDevice Address for the bus on which your TMP102 is connected. The default value is 0x48.

METHODS

getTemp()

$self->getTemp()

Returns the current temperature, in degrees Celsius.

convertTemp()

$self->convertTemp( $reading )

Given a value read from the TMP102, convert the value to degrees Celsius.

LICENSE

This software is Copyright (c) 2014 by Alex White.

This is free software, licensed under:

The (three-clause) BSD License

The BSD License

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright
  notice, this list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright
  notice, this list of conditions and the following disclaimer in the
  documentation and/or other materials provided with the distribution.

* Neither the name of Alex White nor the names of its
  contributors may be used to endorse or promote products derived from
  this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

cpanm Device::TMP102

perl -MCPAN -e shell
install Device::TMP102