help menu

Join us on the Community Forums!

  • Community Guidelines

    The Fitbit Community is a gathering place for real people who wish to exchange ideas, solutions, tips, techniques, and insight about the Fitbit products and services they love. By joining our Community, you agree to uphold these guidelines, so please take a moment to look them over.

  • Learn the Basics

    Check out our Frequently Asked Questions page for information on Community features, and tips to make the most of your time here.

  • Join the Community!

    Join an existing conversation, or start a new thread to ask your question. Creating your account is completely free, and takes about a minute.

Not finding your answer on the Community Forums?

Cancel
Turn on suggestions
Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.
Showing results for 
Show  only  | Search instead for 
Did you mean: 

Inaccurate accelerometer readings

ANSWERED

‎06-12-2018 08:21

‎06-12-2018 08:21

I wrote a simple app following the guides in the dev section of the web site. It takes the accelerometer data and outputs them to the screen. The problem I'm having is that when I lay the watch flat on the table I get the standard 9.8 along the z-axis that I'd expected, but what also accompanies it is extra acceleration along the other axises as well. I was wondering if others are experiencing this, if I got a bad ionic Fitbit, or there's another problem I haven't foreseen.

Best Answer
Labels:
0 Votes
1 BEST ANSWER

Accepted Solutions

‎08-30-2018 11:14

‎08-30-2018 11:14

Okay. So since no one has replied to this topic, I will.

Sensors like the one in the Fitbit and cell phones, are prone to variation/errors in the data that they send. Only much bigger accelerometers  will send data that has very lower number of variation, which making use of them in a watch would make it much too big to put on someones wrist, hence the use of the smaller accelerometer. Depending on the errors produced by the accelermeter (or other sensors), it might be required to use a DC offset to correct some alignment issues, a filter to help estimate the correct data (ex. a Kalman filter), a merging or sensor output, or even use all three. Now I'm definitely not an expert, there may be more ways to go about this. As for now, this hopefully will help those who didn't know about this issue and help them get on the right track to making their app a great one.

View best answer in original post

Best Answer
0 Votes
1 REPLY 1

‎08-30-2018 11:14

‎08-30-2018 11:14

Okay. So since no one has replied to this topic, I will.

Sensors like the one in the Fitbit and cell phones, are prone to variation/errors in the data that they send. Only much bigger accelerometers  will send data that has very lower number of variation, which making use of them in a watch would make it much too big to put on someones wrist, hence the use of the smaller accelerometer. Depending on the errors produced by the accelermeter (or other sensors), it might be required to use a DC offset to correct some alignment issues, a filter to help estimate the correct data (ex. a Kalman filter), a merging or sensor output, or even use all three. Now I'm definitely not an expert, there may be more ways to go about this. As for now, this hopefully will help those who didn't know about this issue and help them get on the right track to making their app a great one.

Best Answer
0 Votes