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  • Author Author: popupideas
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Elevator test unit

popupideas

one diy test unit I want to build is a g-force accelerometer tested for elevators. Prefer a Bluetooth enabled box you put inside an elevator that when it is sent up it will record the travel speed, acceleration, start and stoppong force. It bit I had issues figuring out was vertical speed.

Anyway. I am a loooong way off but maybe one day

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  • Hi Chris,

    The only way to get velocity will be to measure the acceleration and integrate it over the time of the acceleration. If you are lucky and the acceleration is constant then you can get away with just measuring the acceleration and the amount of time it is applied. V=at. Once you have calculated the velocity you can calculate the other parameters. Accuracy of the instrument will all be tied to the accuracy of the accelerometer and synchronization with the timer.

    John

  • in reply to jw0752

    How about a barometric pressure sensor being used as an altimeter. Difference in altitude over time would give you the average velocity for that period. It may only be accurate enough for taller buildings however depending upon the resolution of the sensor. Could combine with the accelerometer data to avoid the acceleration/de-acceleration phases.

  • in reply to beacon_dave

    Just a unverified suspect. The barometric pressure can return a good value if in outdoor. With the few tenth of meters inside the very reduced space of a lift I think there is not a reliable variation really related to the height but there are a number of unpredictable noisy factors.

    Instead I think something I remember from the Nokia age; there was a model with altimeter and - strange - it was working correctly also inside a pesurised plane. IS there some different kind of sensor based on the gravity variation or something else ?

     

    Enrico

  • in reply to balearicdynamics

    Hi Enrico,

    As long as the elevator itself isn't air tight the barometric pressure measurement should work well indoors. It is in fact just a measurement of the force (weight) of a column of air. Even if the building is pressurized there should be a measurable difference between different elevations in the building. The system would have to have a way to zero itself when at the bottom of the shaft, otherwise day to day natural pressure changes would throw off the calibration.

    John

  • in reply to jw0752

    John,

    thank you for this clarification. The good news is that I have understood why altimeter was working on the fly, the bad is that there is not a strange sensor I don't know image

     

    Enrico

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