Copyright © 2009 Eagle Tree Systems, LLC
http://www.eagletreesystems.com
Using Eagle Tree Microsensor V3
TM
Sensors with your
Microcontroller Project
Document Version 1.3
The Eagle Tree Systems Airspeed and Altimeter V3 sensors can now be incorporated in you
microcontroller project. The sensors are accessed via the industry standard I2C bus. The sensors
return the actual speed or altitude, in the units selected as described in the instruction manual that
accompanies the sensors.
Configuring the Sensor for “Third Party” Mode
To configure the sensor to be accessible with your Microcontroller, you must first connect the
sensor to an eLogger V3, and install Eagle Tree Data Recorder software version 7.93 or later.
Follow these steps to switch the sensor from “Eagle Tree” mode (raw data returned via I2C) to
“Third Party” mode (actual airspeed or altitude returned via I2C):
1.
Install Data Recorder software version 7.93 or later.
2.
Attach the MicroSensor to your eLogger V3, per the Microsensor instructions.
3.
Connect the eLogger V3 and Microsensor to USB.
4.
In the Data Recorder software click "Advanced, Custom Hardware Options."
5.
Click the appropriate checkbox (“Use my Airspeed V3 Microsensor with 3rd Party
hardware” or “Use my Altimeter V3 Microsensor with 3rd Party hardware “ to toggle the
sensor(s) between Eagle Tree and third party mode.
6.
When the checkbox is checked, the sensor is placed in Third Party mode. Likewise, when
the checkbox is cleared, the sensor is reverted back to Eagle Tree mode. Note that the
data logged with Eagle Tree equipment will ONLY be correct if the sensor is placed
in Eagle Tree mode.
7.
When the sensor is in Third Party mode, the sensor returns the computed value, in the
units programmed into the sensor by the user. In other words, if the airspeed sensor is
programmed to read MPH, the value returned is in MPH. See the sensor manual on
configuring the units (units cannot be configured via I2C).
Connecting the MicroSensor V3 to your Microcontroller
The pinout of the MicroSensor’s 4 pin cable is as follows:
•
Red wire: Power (3V to 16V)
•
White wire: Ground
•
Yellow wire: SDA (3V to 5V)
•
Brown wire: SCL (3V to 5V)
Note that pull-ups are required on the SDA and SCL lines, and are not provided on the
MicroSensor. These must be added t o your PC board.
Accessing the Microsensor V3 via I2C
