Which sensor to detect movement (from arduino) ?


I need a sensor to detect that my arduino has moved, or more correctly, the box in which my arduino has moved.
I have two needs : it must be the smallest possible (I will probably use arduino nano/mini/trinket or something) and it should be able to cache the data (moved or not).

The closest thing I saw that will accepts my specs is an accelerometer. It's a bit overkill since I don't need the actual speed but hey I don't think anything other than that exist.
I have a problem with it though : it's battery powered and it's small, I will need to get the speed (movement) after minutes of delay/sleep from my arduino. I suppose that if I move my arduino (so the speed is > 0) but I don't read it yet, then stop moving it. I sleep for 5 minutes then I read the accelerometer value the speed from my axes will now be 0 or close to zero right ? I suppose it decelerate with time or something.

So my question is, is there an accelerometer (or other sensor) that can get the biggest movement speed in a time span ?

I've never tried any accelerometer so they may already do that, didn't see any information about it though.

Thank you.

I find your question a little hard to follow, but

  1. I think an accelerometer is the minimum sensor you would want, but

  2. any accelerometer I have checked out doesn't store any data itself, it just forwards the raw x,y,z acceleration data to the processor, which then has to sort out what the speed/direction is. If you find an accelerometer that has an available alert signal when it becomes active, perhaps you could let your Arduino sleep indefinitely, and wake it up only with an interrupt from the accelerometer.

There are plenty of tutorials out there on the sleep/wakeup process.

Good luck.

A tilt sensor may do the trick, and wake up the Arduino when activated. Take care to pick an sensitive sensor, or build your own.

Most recent accelerometer designs feature one or more programmable interrupts, which will wake the processor from sleep if a certain acceleration is detected (including free fall). Here is a randomly chosen example: NXP® Semiconductors Official Site | Home

Excellent, I didn't think about interrup.
Thank you, that exactly what I need, looks smaller than the one I saw also, great !