Detecting lift (elevator) motion.. accelerometer or which sensor?

Status
Not open for further replies.
M

mubase

Member
Hi guys. Me and my GF are having loads of fun with our new Teensy 3.2 boards. Been wanting to use the Teensy 3 for years and now we have arrived. :)
I have a question regarding a project we are working on. We want to trigger spoken word audio samples. We have the brilliant audio board to work with but are stuck with a sensor proble.
We'd like to know if it is possible for an accelerometer to detect whether a lift is moving up or down because we want to trigger different sound samples according to whther the lift is moving up or down. Can we do this using just the accelerometer data? We have a couple of them. One is an MPU9150 9DOF and the other is an analogue accelerometer (MMA7361.)
Any help appreciated.
Thanks,
SteveS
 
With it's range of +/- 2 g, the MPU-9150 has plenty of sensitivity to detect the motion of the elevator (lift).
The tricky part will be filtering out vibrations caused by people boarding and doors opening, etc.
 
I don't know how much vertical oscillation your elevator has- some have a lot as people get on and off which you would have to filter out. A pressure sensor can give you an elevation directly, apart from the slow background change in atmospheric pressure. The good thing is the pressure should be completely insensitive to vibrations, and should easily tell you when a lift is stopped, moving up, or down. There's one on the new PJRC Prop Shield, it is the MPL3115 which claims to resolve a 10 cm altitude change.
 
One problem with using a barometer/altimeter is that many elevators have a ventilation fan inside that could cause spikes as the doors open and close.
That might also be useful information as one might be able to detect door position.

I concur that the altimeter and accelerometers on the Prop Shield are extremely stable and sensitive.
I was easily and cleanly able to see altitude differences from floor to ceiling (slightly less than 8 ft)
 
Last edited:
mubase,

A good first step might be to set up your Teensy as a data logger and record barometer and accelerometer data on the lift to see what you'll need to deal with.
This sounds like fun science!
 
Status
Not open for further replies.
Back
Top