How to find 'g' from a MEM's Device (Shimmer IMU)?

  • Thread starter bsa09
  • Start date
  • Tags
    Device
In summary, the conversation discusses using an accelerometer to detect movement and obtaining values between 1000 and 2000. The question is whether these values are the output of the ADC and how to calculate 'g' from them. The suggestion is to calibrate the device using Earth's gravity or referring to the device's documentation for more information. Other calibration methods, such as using a spec sheet, are also mentioned.
  • #1
bsa09
1
0
Hello all,
I'm working with an accelerometer to detect movement and I'm using Shimmer IMU. I got values ranging somewhere between 1000 and 2000. My question is, are these values the output of the ADC? And how do i calculate 'g' from the values?
I have attached an xls file with the experiment readings.
Thank you
 

Attachments

  • readings_zipped.zip
    88.3 KB · Views: 286
Physics news on Phys.org
  • #2
The device must have some documentation with it. Which should explain what those values are.
 
  • #3
Probably the easiest way would be to just calibrate it using Earth's gravity - most accelerometers output voltage is linearly proportional to the acceleration, so all you need is two points to calibrate it. If you hold it vertically, such that the measurement axis is aligned with the gravitational force, you can get one such calibration point (9.8 m/s^2), and then you can get the second calibration point by holding it horizontally (0 m/s^2) or upside down (-9.8 m/s^2). You could even do all three, and then do a best fit line to determine a slightly more accurate reading.

Alternatively, there's probably a spec sheet somewhere, but how useful it is will depend on your setup.
 

1. How does a MEM's device measure 'g'?

A MEM's device, also known as a microelectromechanical system, uses tiny microsensors to measure acceleration. These sensors detect changes in the device's orientation and movement, and from this data, the device can calculate the acceleration due to gravity, also known as 'g'.

2. Can any MEM's device be used to measure 'g'?

Most MEM's devices are designed specifically for measuring acceleration, so they can typically measure 'g'. However, the accuracy and sensitivity of the device may vary. It is important to check the specifications of the specific MEM's device to ensure it is suitable for measuring 'g'.

3. How do I interpret the data from a MEM's device to find 'g'?

The data from a MEM's device is typically in the form of acceleration values in the x, y, and z directions. To find 'g', you will need to take the square root of the sum of the squares of these values. This is known as the magnitude of acceleration and will give you the total acceleration including the acceleration due to gravity. You can then subtract the acceleration due to other forces, such as movement or rotation, to isolate the acceleration due to gravity.

4. Is it necessary to calibrate a MEM's device before finding 'g'?

Yes, calibration is important for accurate measurements. Calibration involves setting the baseline values for the device and accounting for any errors or variations in the sensors. This can be done by placing the device in a known orientation and measuring the acceleration values. The calibration values can then be used to adjust the data and improve accuracy.

5. Can I use a MEM's device to measure 'g' in any location?

Yes, a MEM's device can measure 'g' in any location as long as it is not affected by strong magnetic fields or extreme temperatures. However, it is important to note that the value of 'g' may vary slightly depending on the location, as it is affected by factors such as altitude and latitude.

Similar threads

  • Other Physics Topics
Replies
20
Views
2K
  • Mechanics
Replies
1
Views
5K
  • General Engineering
Replies
7
Views
3K
Replies
9
Views
1K
  • General Discussion
Replies
13
Views
891
Replies
7
Views
2K
  • Mechanics
Replies
10
Views
2K
  • Programming and Computer Science
Replies
3
Views
1K
  • Electrical Engineering
Replies
3
Views
790
  • Quantum Physics
Replies
1
Views
700
Back
Top