Accelerometer mma8551 response time

baudetd · May 10, 2015, 9:00pm

hello

I use an accelerometer mma8151 but I find the response time are quite long.
is what has of the accelerometer
or the i2c protocol?
what is the difference with ADXL345 accelerometer ?
Thanks

hugo · May 11, 2015, 4:56am

Response time from what to what? I2C isn’t terribly fast, but without knowing the order of magnitude of the problem (and what the problem is) it’s hard to give advice

baudetd · May 11, 2015, 6:50am

when I use a mma8451 accelerometer , there is a slight delay between the movement and value.
the time is about 0.5 seconds

I use this code:

gist.github.com

https://gist.github.com/duppypro/7225636

Sample_MMA8452Q_Device.nut

// Sample code using MMA8452Q accelerometer
// Electric Imp Device Squirrel code
// License:
// This code is provided under the Creative Commons Attribution-ShareAlike 3.0 License
//    http://creativecommons.org/licenses/by-sa/3.0/us/legalcode
// If you find bugs report to duppypro on github or @duppy #MMA8452Q on twitter
// If you find this useful, send a good word to @duppy #MMA8452Q
// Thanks to @jayrz for finding the first bug.

/////////////////////////////////////////////////

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hugo · May 13, 2015, 3:28am

The delay may just be in the logging (if you’re looking for a log message - that’s going a long way to appear in your browser).

Try putting an LED on another imp pin and triggering it in the interrupt handler. That gives a real measure of when the accelerometer is interrupting.