Module/LM75

From PaparazziUAV
Jump to: navigation, search
LM75 in hot glue

Overview

The National LM75 (now Texas Instruments LM75A) is an affordable temperature sensor that could be used e.g. to measure battery temperature.

Module name meteo/temp_lm75
Sensor type temperature
Range -55°C .. +125°C
Resolution 0.5°C
Refresh rate 3Hz
I2C address 0x90

TI product homepage

Hardware

The LM75 can be directly interfaced to the Paparazzi autpilot 3.3V I2C interfaces.

Wiring

Autopilot I2C pin Autopilot I2C LM75
1 GND GND
2
3 +3.3V +Vs
4 SDA SDA
5 SCL SCL


Usage

To use the temperature sensor add the module to your airframe file.

File: conf/airframes/myplane.xml
  <modules>
    <load name="temp_lm75.xml"/>
  </modules>


Result message

The raw data (itemp) and the converted result (temp) is written to the log file. The message is automatically sent when new data is received, it does not have to be added to the telemetry file.

File: conf/messages.xml
  <message name="TMP_STATUS" id="86">
    <field name="itemp" type="uint16"/>
    <field name="temp" type="float" unit="deg_celsius" format="%.2f"/>
  </message>


Sample log file lines

2.663 TMP_STATUS 123 45 22.5
2.908 TMP_STATUS 123 46 23.
3.333 TMP_STATUS 123 47 23.5
3.665 TMP_STATUS 123 47 23.5