Elevator test unit

RE: Elevator test unit

jw0752 — Wed, 30 Aug 2017 01:52:01 GMT

Another aspect of elevators that might be problematic is that they usually take a couple seconds to settle or completely stop as they reach their destinations. Due to the low velocity and deceleration at these points the time becomes the dominate parameter and will likely throw off calculations of distance and velocity.

John

RE: Elevator test unit

dougw — Tue, 29 Aug 2017 16:46:19 GMT

You can figure out (or calibrate) the distance by the trip time, because the precise distance is quantized (by the number of floors).

You can get the average speed by dividing the distance by the time of the trip.

If you plot the number of floors versus the average speed it will be a curve because the acceleration & deceleration will be less of a factor on longer trips.

The asymptote of the curve will be the actual speed.

Individual trip speed just requires a small time (about equal to the accel & decel time/2) subtracted from the trip time before dividing distance by time to get speed.

A Bluetooth arduino is more than adequate for this task. It would need an accelerometer to detect the stop at each floor.

If you know the distance it travels at constant speed, the accelerometer can tell when the speed is constant, so the distance divided by the time it spends at constant speed is the speed.

RE: Elevator test unit

popupideas — Tue, 29 Aug 2017 15:02:39 GMT

Thank you everyone for the input! wow.

I don't know if the following information would be helpful but:

You can do a pretty decent calculation of travel distance on most elevators (there are exceptions that one would have to measure)

And the Acceleration and deceleration distances are usually consistent. 18-26 inches. Because these numbers are rough I know it would not give extremely accurate information.

I never considered the barometric pressure option. I will have to look into that a bit more. I had considered this idea for a unit would also be useful for diy rocket and NEO balloon projects.

Thank you again for everyone that gave their time and thoughts to this.

RE: Elevator test unit

DAB — Mon, 28 Aug 2017 18:14:36 GMT

Interesting Idea.

I would go with an RPi with a sensor hat.

You get the 3-axis accelerometer, temp, humidity, and I think a barometer and magnetometer.

DAB

RE: Elevator test unit

jw0752 — Mon, 28 Aug 2017 02:46:51 GMT

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