| Parameter | Value | Unit
|
|---|---|---|
| Vcc | 3-6v | V^1
|
| Current with USB | 25 | mA
|
| Current without USB | 17 | mA
|
| Current in powerdown mode | 80 | uA
|
| Startup time | 300 | mS
|
| Pitch/Roll Accuracy | 0.2 | deg^2
|
| Pitch/Roll Precision | 0.04 | deg
|
| Yaw Accuracy | 1.5 | deg^2
|
| Yaw Precision | 0.01 | deg
|
| Accelerometer range | +- 2 | G
|
| Magnetometer range | +- 6 | Gauss
|
| Accelerometer output rate | up to 500 | hz
|
| Magnetometer output rate | up to 64 | hz
|
| Accelerometer bandwidth | 10 bits @10 hz | per G
|
| Magnetometer bandwidth | 13 bits @10 hz | per gauss
|
| Temperature Accuracy | +- 5 | deg F
|
| Temperature Precision | +- .3 | deg F
|
1 Can be powered via USB
2 with good calibration
| Parameter | Value | Unit
|
|---|---|---|
| White Backlight Current | 8 | mA
|
| Green Backlight Current | 4 | mA
|
Battery charges from usb with a max of 100mA.
| Parameter | Value | Unit
|
|---|---|---|
| Battery Type | 3.6v lipo |
|
| Battery Capacity | 250 | mAH
|
| Battery Charge Current | 100 | mA
|
| Charge time | 4 | hours
|
| Run time | >10^1 | hours
|
1 decreases with age and backlight usage
Various capacitors resistors and connectors see schematic for details
This chapter describes all of the data available on the device. It assumes use of the dataclient. It should be obvious how to use the DataViewer as well. Each section begins with the name of the directory.
The openmag project operates an accelerometer, magnetometer, and temperature sensor. If the device is to be used while moving, the calculated pitch, roll, and yaw are invalid due to lack of gyro compensation. If the down vector is not known, the magnetic vector output is still useful as it is not affected by acceleration, but yaw calculation is impossible.
The accelerometers are in sensor coordinates, the calibrated magnetometer is aligned to the accelerometer, so both calibrated outputs are in sensor coordinates. Box coordinates are another coordinate frame which can be defined by the user, there is a rotation to get from sensor to box coordinates. There is also a rotation to get from sensor to laser coordinates.
Do not be alarmed if you do not have all of the accessors listed, or you have accessors which are not listed here, they may change depending on software version.
This directory contains all of the other directories. It contains the “softwareversion” accessor for determining what software version you are using.
The accessors relevant:
Note: the device does not sleep when plugged in via USB.
The sleep types supported:
Note: If wakeonmotion is set, because extra power is needed to be able to wake from motion, and the device sleeps from being still, the device will consume about 1.5% of normal operating power in powerdown mode rather than 0.5%.
There are 4 types of autocalibration:
The device can store various measurements
The menu on the device is simple, press the key of the number letter or symbol which next to the word or icon you want to perform. The main menu allows you to select a function for the device. It is always possible to press 'D' repeatedly to eventually return to the Main Menu. It is usually possible to press 'A' to read information about the current page.
The compass shows a 3d compass as well as other statistics.
The survey system allows you to take measurements of incline and azimuth using the laser. These measurements may be recorded. Typically there is enough storage for at least 500 shots. It is also possible to enter attributes to go with each measurement (such as distance between survey points) but not required.
To make a measurement from the survey menu, hold '1' down and the laser will turn on, when you release it, a second later the laser will go off and the current reading is locked.
Once held, you can store the measurement with '2'. If this should be a backsight for the last shot, press '3' to toggle to backsight mode. If you want to enter distance LRUD, or other parameters, enter the attributes with '4' before storing.
Data required to store a shot, the minimum is 5 bytes for header, incline and azimuth, additional attributes add:
| Name To | Dist | Incline | Azimuth | LRUD | bytes
|
|---|---|---|---|---|---|
| AFF-001 AFF-002 | - | +42.2 | 135.3 | 15
| |
| AFF-002 AFF-003 | - | -26.7 | 167.4 | 5
| |
| AFF-003 AFF-004 | 23.4 | +35.2 | 302.7 | 7
| |
| AFF-003 AFF-005 | - | -42.1 | 253.9 | 1 1 2 3 | 19
|
The first measurement uses an extra 10 bytes because there is no measurement before it. The fourth measurement uses 5 bytes normally, 4 more for lrud, and 10 more because the number is not sequential.
The measurements can be downloaded to a computer, or viewed on the device.
The pedometer uses a simple algorithm to detect steps by sensing verticle motion. It counts steps with a given tolerance.
The gaussmeter allows you to measure magnetic fields in gauss. There is support for absolute, relative and vector magnetometer modes.
View various statistics about the running program.
Proper calibration is extremely important for accurate measurements. The device can be re-calibrated at any time without any additional equipment. The on-screen help system explains what each step of calibration does.
There are a few settings that can be modified on the device, there are far more settings that can be modified via the dataclient.