13
votes
Do MEMS or optical gyroscope record Earth's rotational and revolutional angular velocities?
Be sure to calculate the level of those signals and compare with the offset, noise and drift of the Android gyroscope chip.
Generally speaking, measuring the earth's rotation with a gyroscope has not ...
9
votes
ADC chip for multiple simultaneous conversions
Use a simultaneous sampling ADC. Difficult hardware but easy software. Can get away with the lowest sampling rate.
Just sequentially sample through the channels with a multiplexed
ADC.
You can sample ...
- 57.3k
8
votes
Do MEMS or optical gyroscope record Earth's rotational and revolutional angular velocities?
What is the reason that the device is calculating a rotational speed
of 0.26 deg/sec even when the device is stationary?
The non-zero numbers your device shows when it is stationary is called a zero ...
- 473k
6
votes
What is the difference between cheap and expensive GPS receivers?
The differences between a cheap GPS and a high end commercial GPS:
Narrow band RF front end Vs wide band front end.
A cheap GPS will only track L1 C/A which is a fairly narrow signal, a good GPS will ...
- 6,992
6
votes
How to resolve the drift around the z-axis in an IMU6050 gyroscope?
The accelerometer doesn't see changes in gravity when you rotate around the vertical z-axis, so you can't use it as an input for a complementary filter (or any other filter/algorithm) to compensate ...
- 9,310
6
votes
Accepted
IMU BNO055 Alternative?
The fate of BNO055 is unknown at the moment. Quite for a long time Bosch was pushing its own alternatives without pre-programmed fusion software, like BMF055. On one hand it allowed developers to make ...
- 13.1k
6
votes
I2C scan returns more devices than connected
Addresses of the form 0000XXX and 1111XXX are reserved for various purposes; you should not scan them.
- 20.1k
5
votes
What is the difference between cheap and expensive GPS receivers?
See How many GPS channels make sense?
That long answer details how adding more channels to a reciever (at additional cost) can:
Speeds up satellite acquisition
Reduces power consumption
Reduces ...
- 47.1k
5
votes
Accepted
How is Gyro drift error related to error in velocity and position?
In a typical pure inertial nav solution, you must cancel out the acceleration due to gravity by subtracting it out. If the vehicle's down vector is incorrect, this error appears as a lateral ...
- 47.1k
5
votes
Accepted
What is the correct maximum sample rate for the MPU-6500? Most of the internet says 32kHz, the datasheets say this isn't likely
I can't explain what the MPU-6500 does at 32kHz, but it does appear that it really can do it.
Setting sample rate to 32kHz.
Table 4 from the datasheet says you can do it:
Setting the sample rate to ...
- 73.6k
4
votes
Accepted
Serial Peripheral Interface (SPI) vs Two-Wire Interface (TWI, I²C) wire length
The limiting factor is the capacitance of the interconnecting wires. A pair of wires has a capacitance between them, measured in \$Fm^{-1}\$. Therefore, as your wire length goes up, the capacitance ...
- 7,999
4
votes
What actually causes gyroscope drift in IMU?
I always understood drift to be DC bias (you can think of it as a voltage offset inherent in all amplifiers and some sensors, even metal junctions can contribute to voltage offsets.) But its a little ...
- 88.8k
4
votes
Accepted
MPU6050 losing orientation
(MEMS) gyroscopes measure rate of change, not angles or orientation. A gyroscope at rest has a zero rate of change, and will show zeros.
You need to integrate over time to get a rotation angle. Better ...
- 9,310
4
votes
ADC chip for multiple simultaneous conversions
As currently written, the question lacks a lot of important information, including the nature and bandwidth of the incoming signal.
That to one side, your maximum sample rate is the vaguely 'a few kS/...
- 23.8k
4
votes
SPI bus termination for variable line length / variable number of slaves
I think you are really swimming against the tide here. You are asking for theoretical background, I'll do my best.
The point about SPI termination is not about bus speed, but that the whole thing ...
- 7,933
4
votes
SPI bus termination for variable line length / variable number of slaves
Slave response delays due to cable length create a sync problem in SPI
A 4 metre cable of average sort of characteristics will delay a clock edge by about 20 ns from one end to the other. This is ...
- 473k
4
votes
Do MEMS or optical gyroscope record Earth's rotational and revolutional angular velocities?
My end goal is to design a system which records the orientation of the device in 3D space for a time period of 24 hours. I am using integration for the recorded angular velocities to find the angular ...
3
votes
Accepted
Converting MPU-6050's quaternion output to YPR angles
Before I answer, it should be noted that there are some benefits to using quaternions:
They avoid gimbal lock (important for devices that may be turned upside down)
Quaternion transformations and ...
- 1,341
3
votes
Does multiple IMU increase accuracy
Yes, you can use multiple sensor units to improve the data, but only if their errors — biases, scale factors, noise, etc. — are independent (uncorrelated). In that case, you can expect the ...
- 178k
3
votes
Accepted
Drone gyroscope placement
In an ideal world, there's no difference between placing a gyro at the center of mass or at the very end of an arm. In practice the frame might flex under flight loads, causing a different angular ...
- 8,681
3
votes
Accepted
No response from ST LSM6DS3 IMU breakout board using SPI
[Since this was confirmed as the solution from my comment, here it is as an answer:]
The SparkFun LSM6DS3 breakout allows either the device's SPI or I2C interface to be used. However, the breakout ...
- 18.3k
3
votes
Accepted
Which is give better result for find angular position of device using 9-axis IMU snesor.?
Thanks a lot to all for your greater Support.
I have found some interesting Reference website. which give the best method to implement both to find meaningful data like, pitch & Roll.
Guide to ...
- 157
3
votes
Which is give better result for find angular position of device using 9-axis IMU snesor.?
You need some kind of algorithm to fuse the acceleration, rotational rate and magnetic field readings. There are several different ways to do this, from simple complementary HP/LP-filters to more ...
- 31
3
votes
Which is give better result for find angular position of device using 9-axis IMU snesor.?
Generally you determine angle by using the accelerometer readings. This only works is the unit is not accelerating at the time but you can do a quick sanity check that sqrt(x*x + y *y + z *z) = 1g +/- ...
- 6,992
3
votes
How to calculate the orientation of a IMU sensor?
As you've discovered, a three-axis accelerometer will only tell you the orientation when something is basically stable. Or, stable on average if you can tolerate a slow response due to the filtering ...
- 146
3
votes
What actually causes gyroscope drift in IMU?
The second quote is more accurate than the first. Integration causes drift, but not just because of the frequency response of the integrator.
There are two primary components of the input signal that ...
- 178k
3
votes
Accepted
Can I measure vibrations with an IMU that has lower frequency than the vibrating object?
That particular product uses an LSM9DS1 MEMS IMU.
When you set the frequency, you are setting the frequency cutoff of the internal anti-aliasing filter.
There should be minimal aliasing, but the ...
3
votes
What is the correct maximum sample rate for the MPU-6500? Most of the internet says 32kHz, the datasheets say this isn't likely
What really is the true useable sample rate for the MPU-6500? Can one
put the IMU into a mode where is vomits out ~3Mbps worth of gyro/accel
data, or is most of the internet wrong, or reading the ...
- 57k
3
votes
Accepted
I2C scan returns more devices than connected
Private address I2C and MIPI I3C. See you datasheet.
- 15.8k
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