Questions tagged [magnetometer]

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10
votes
2answers
2k views

Why do compass chips in cellphones require frequent calibration?

Most cell phones offer digital compass functionality which uses a 3-axis magnetometer chip for data. Phones (some more than others?) frequently require the user to "recalibrate", which ...
2
votes
1answer
249 views

What is the difference between IMUs and other devices that have accelerometers and gyroscopes (smartphones, tablets, sensewear etc.)?

The general definition of IMU says that any device that has accelerometer, gyroscope and magnetometer/GPS packed together is an IMU. Then why aren't other devices that have the same sensors called ...
1
vote
2answers
213 views

TWI/I2C Protocol with HMC5883L Magnetometer with ATMEGA256RFR2 XPLAINED PRO (megaavr)

Im trying to read Data Output Registers of X,Y,Z So far I've been able to: ...
1
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2answers
1k views

Bosch BNO055 gyroscope bias stability

What is the bias stability in degrees/hour of the gyroscope on the BNO055? The datasheet lists some specs of the gyro on page #14 but I cant find the bias there. There is an item called "output noise"...
2
votes
1answer
215 views

accuracy of magnetic field sensors in electrical vehicles

For coordinate system alignment purposes, as demonstrated in the figure, I want to use the smartphone's virtual orientation sensor. However, the virtual sensor is using a combination of acceleration, ...
0
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1answer
214 views

MEMS 6 axis: acc + mag or acc + gyro?

I have a question which I can not give an answer even if it is some days I am thinking about that. In general a INS is made by an accelerometer + a gyroscope. Is it possible to obtain the same ...
6
votes
1answer
10k views

Accessing magnetometer results in MPU-9250

I am interfacing an MPU-9250 to an STM8S207 microcontroller. The MPU-9250 is accessed via 400kHz I2C. I have no isses with getting measurement data from the temperature, gyro and accelerometer, but ...
0
votes
1answer
421 views

Is LSM303dlhc INT1 active HI and DRDY active LO?

I just want to make sure I am approaching my LSM303DLHC design properly, and that I'm correct in the active state of the two pins. I setup the following registers as indicated: ...
1
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2answers
5k views

Why also using magnetometers in IMUs?

Why do we also use magnetometers when building IMUs, that is why don't we simply and only use gyroscopes and accelerometers? I also would like to know how does a magnetometer work as a 3-axis device? ...
1
vote
1answer
898 views

Bricked IMU using a magnet?

I think I may have bricked my IMU or seriously damaged it earlier this week. I have the Adafruit 9-DOF IMU Breakout - L3GD20H + LSM303 (link: http://www.adafruit.com/products/1714) which has an ...
0
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2answers
1k views

LSM303DLHC outputs frozen

I've was trying all afternoon yesterday to get some data out of my LSM303DLHC using an STM32L152 Nucleo board. Finally I got all the I2C stuff down, managed to set some registers, verify their ...
2
votes
1answer
821 views

What can cause magnetometer offset to be variable?

I'm a using a embedded MEMS 3-axis magnetometer. With 'embedded' I mean that I am using an Android device with a magnetometer. I am not doing the low-level control myself, only retrieving measurements....
1
vote
0answers
132 views

Magnetometer perpendicular to ground plane

A team and I are building some wearable tech that needs a magnetometer to know your heading. Unfortunately, we have to mount it "vertically" - imagine that the board is flat against your stomach/waist....
1
vote
1answer
616 views

Error in Magnetometer Readings

I have a magnetometer which I am using for orientation purposes. What i would like to know is how to calculate the total error when finding the magnitude of the magnetic field vector. So I know each ...
1
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1answer
153 views

3 axis magnetometer issue in one axis

I have several 3-axis magnetometers mounted on breadboards, and they all read correctly in the x and z directions. The Y direction is very strange; when turned to read ...
2
votes
2answers
328 views

How build coil for respiratory magnetometer or find a better option (hall effect)?

I am trying to build an respiratory magnetometer. This device is no longer widely used even thought it was well liked. The reason it is no longer used is due to the fact that the coils used in it were ...
1
vote
1answer
266 views

Would proximity to water affect a magnetometer

I'm using an InvenSense MPU9150 as a tilt-compensated compass in an autonomous sailboat. I'm trying to decide where to put the the control board, with options being in a dry box on top of the "deck," ...
4
votes
4answers
13k views

How to connect multiple of the same device to an Arduino using I2C?

I want to use two of the same magnetometer (HMC5883L) with my Arduino, but I cannot figure the code for calling each of them separately. I have read online that connecting multiple devices is ...
0
votes
1answer
3k views

What are the limitations of IMU sensor devices?

The Oculus Rift DK2 virtual reality headset uses an IR camera in conjunction with built-in accelerometer/gyro/magnetometer for accurate head/motion tracking. The previous version (DK1) used only an ...
3
votes
2answers
1k views

Magnetometer tilt compensation without accelerometer

I need to use the magnetometer in a device to accurately determine how many degrees the user twists (rotates in x-y plane) it. I don't care about absolute orientation, just the angular delta. Of ...
1
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4answers
8k views

How do I determine the distance from a magnet using Magnetometer?

I have a triple-axis magnetometer and a magnet, and I am trying to calculate the relative position of the magnet from the magnetometer. The magnetometer outputs the strength of any fields detected in ...
0
votes
1answer
1k views

Regarding Direction calculation using Gyroscope,Magnetometer and Accelerometer

We are using a MEMS tri-axial sensor which has an Accelerometer,Magnetometer and Gyrometer. We have also calibrated the Accelerometer and Magnetometer.This sensor package is used in a borehole ...
10
votes
1answer
11k views

AHRS algorithm under continuous linear accelerations

I have tried several algorithms to get pitch, roll and yaw under continuous linear accelerations and vibrations (smaller than 0.4g, frequency lower than 10HZ). None of them give good results because ...
2
votes
2answers
299 views

Sensoring gokart pedals?

I want to make a ATMega-based module to record several parameters of a go-kart while driving - pedals position, speed of the wheels and g-forces. I have a problem with choosing how to measure gas and ...
2
votes
1answer
713 views

SensorTag- Magnetometer to compass

I have a sensor tag from Texas and have been able to communicate with it over BLE and get magnetometer readings using a node.js library. However I am tough time going from the x,y,z mag. axis ...
4
votes
1answer
2k views

Can a 3-axis magnetometer be tilt compensated when moving/accelerating?

I have a magnetometer, accelerometer and gyro which all go swimming (attached to a person.) Data is logged and I now have a sample of that data. I want to calculate the magnetic heading the user was ...

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