Eagle Tree Systems GFORCE-HIGH, GFORCE-LOW User Manual

Instruction Manual for the 3 Axis G-Force MicroSensor

Model Numbers: GFORCE-LOW, GFORCE-HIGH

Document Version 1.2

Thank you for your purchase! This instruction manual will guide you through the installation and operation of your G-Force MicroSensor (the G-Sensor). The latest version of this manual is available in the Product Manuals section of the Support tab on

http://www.eagletreesystems.com. The online manual includes any updates that were made after this manual was printed. Please read the

entire manual carefully before proceeding.

Packing List

Your package should include the following: The G-Sensor, the Standalone Cable, and a printed version of this manual.

Intended Uses

The G-Sensor is intended exclusively for recreational use in radio control models and model rockets. Other uses are not supported.

Further, using the G-Sensor in situations where its use or failure could result in loss of life, bodily injury or property damage is expressly prohibited.

Want to use the G-Sensor for your own hardware/firmware project? Read on in the manual for more information!

Have questions or Feedback?

Eagle Tree is committed to providing great customer service. If you’ve read the manual and something is not clear, just ask. We’d much prefer to take the time to answer your questions, rather than having you waste your valuable time struggling with an issue.

To get help, visit the Eagle Tree G-Sensor support thread at http://www.rcgroups.com/forums/showthread.php?t=1454098. Chances are someone has posted a solution to your problem already. If not, posting your problem there will get a very quick response from the Eagle Tree community. If you prefer to not post on the forum, or you feel there is a problem with your Eagle Tree hardware, please open a support ticket with us at http://ticket.eagletreesystems.com

What the G-Sensor Does

The G-Sensor is a precision 3 axis accelerometer that constantly measures change in acceleration in the X, Y and Z axes. The unit of acceleration measurement is the “g,” which equals the force of gravity (9.81 m/s2). So, when the G-Sensor reads 2 g, for example, this equals 2 times the force of gravity.

The GFORCE-LOWG model measures and records acceleration to at least +/- 7 g in each axis. The GFORCE-HIGHG model measures to at least +/- 38 g in the X and Y axes, and to at least +/- 7 g in the Z axis. The readings may be inaccurate if these values are exceeded.

When used standalone, the G-Force sensor repeatedly displays the maximum acceleration encountered in each of its 3 axes, on the built in 7 segment LED display. These maximum values are stored to non-volatile memory, so when power is disconnected they are preserved.

Additionally, the G-Sensor can be connected to your eLogger V4 or V3 to provide acceleration data for your entire flight. When connected to the eLogger, the acceleration in each axis can be displayed and graphed using the eLogger’s Windows software. NOTE: the G-Sensor is

NOT compatible with our prior eLogger V1 or V2 or our Data Recorder products.

Installing the G-Sensor in your Model

The G-Sensor can be mounted with double sided tape, Velcro, or similar. The G-Sensor is normally mounted flat in the model, with the label down, and the “Y” arrow on the label facing toward the direction of travel. When mounted this way, the Y axis points in the direction the model travels, the X axis is horizontally perpendicular to the direction that the model travels, and the Z axis points toward the top of the model (normally toward the sky). With this mounting configuration, acceleration in the forward direction will show up as positive Y values, and acceleration in the up direction will result in positive Z values. Note that the force of gravity is 1G, normally in the direction of the Z axis.

Page

If you have the High G sensor, and wish to measure vertical force greater than 8 g, you can mount the sensor so that either the X or Y axis is vertical.

Range check: It is extremely unlikely that the installation of the G-Sensor will affect your model’s radio range or control. But, as always after making an electronics change to your model, it is very important that you range and function test your model once the G-Sensor is installed to ensure that there is no impact on your system.

Using the G-Sensor in Standalone Mode

Powering the G-Sensor in Standalone Mode

For standalone mode (not connected to an eLogger), connect the Standalone Cable to the gold pins of the G-Sensor, as shown in Figure 1. The polarity of the connection is as follows: RED = Positive (Vdd) BLACK = Negative (ground)

Note that the RED wire of the standalone cable corresponds with the red dot on the label.

The JR/Universal servo end of the Standalone Cable connects to a spare Receiver channel or small battery. Note that the voltage must be between about 4V and 16V (4V to 6V for the High G sensor). Do not exceed 16V with the low G sensor, or 6V with the High G sensor!

IMPORTANT: Ensure that you connect the Standalone Cable with the correct polarity, or the G-Sensor could be damaged, voiding the warranty! Note that in Standalone Mode, the 4 wire cable built into the G-Sensor must NOT be connected to anything!

The Trigger G-Force

Upon power up, the G-Sensor will display a single digit representing the “trigger” G-Force. This represents the number of g’s (either positive or negative) that the sensor must experience on at least one of its axes before it will overwrite the previous session’s maximum values with new readings (after power is disconnected and reconnected). The trigger G-Force can be changed as described below.

Display of the Maximum Values Encountered

After power up, the G-Sensor repeatedly displays the maximum values that were last captured, cycling through the X, Y and Z axes. When displaying the values, the LED first displays the axis symbol, then the G-Force reading for that axis. It does this sequentially for each axis in the order of X, Y and Z.

The value itself for each axis is displayed with the sign first (if negative), then the most significant digit, followed by each successive digit down to the first decimal place.

In the example at right, the maximum values detected during the session were: X = 0.6 g, Y = 4.1 g,and Z= - 3.2 g.

Note that the “absolute value” of readings is used to compute the maximum. For example, a value of -2 g sensed by the G-Sensor is greater than a value of +1.5 g, and hence -2 will be displayed for that axis.

During a session, once the trigger G-Force is encountered on any axis, the sensor then records all the values at that moment as the maximum values. Then, during the rest of the session, any value for a particular axis that is greater than the presently recorded value for that axis, replaces the prior recorded value. So, at the end of the session, the maximum values encountered in each axis are displayed.

Rearming the Trigger G-Force

When the G-Sensor is disconnected from power and reconnected, the values stored from the last session are still displayed. But, the power cycle rearms the trigger G-Force. When this trigger G-Force is encountered in your next session, the values from your last session are overwritten with the new maximum values, even if the new maximum values are less than the maximum values you encountered in your last session.

Changing the Trigger G-Force

By default, the trigger G-Force is set as 2 g. The other available values are 3, 4, and 5 g.

+ 2 hidden pages