# Device For Measurement Of Motion In Buildings.

Dear Friends, Point by Point: 1. I am an Architect in Rotterdam, Netherlands. 2. I Want to Measure The Movement by Windforce of my Building(s), at the Highest Point. 3. Measurement Device: Gyroscope, Accelerometer. 4. I want to Stream The Data by Wifi, to a site 'Initial State' for Graphics. So I can See Anomalies. 5. So I want to build a Measurement Device with: Gyroscope, Accelerometer, Wifi, electric Current, (embedded) Code, Waterproof Case. 6. I am a little familiar with Arduino.

I need Help. Is there anybody who can tell me which Boards or Shields I must Use? Libraries, Codes For Measurement and Streaming? Thank You. Kind Regards, Jandirk Van Oosten

I'm curious what you are going to do with the data. Once the building has been built, it's a bit late to be trying to deal with a building that flaps like a flag in the wind.

I think the idea might be to calm a complaining customer rather than alter the building. If you can throw one onto the roof of the neighbor and show their building moves twice as much then you have a happy customer.

It’s a tricky thing to measure with the cheap accelerometers like ADXL345. I think it can be done but I haven’t tried. Integrating acceleration to get distance will be wildly inaccurate but just logging acceleration and showing peak acceleration would go a long way to identifying and characterizing the problem. Gyros will be basically useless.

I doubt very much that a consumer-grade accelerometer can measure the acceleration of a building, when the force is provided by typical wind velocities.

However, suitable devices certainly exist (for example, the sensor element could be based on a simple pendulum), so I suggest to consult architects at a nearby university. Perhaps a measuring device could be borrowed.

How about a heavy ball bearing (like a bowling ball) held in a static position by load cells around the horizontal circumference. As the building moves the inertia of the ball causes it to load and unload opposite pairs of load cells.

I wonder if you couldn't do this with lasers set up in elevator shafts? There might be enough clearance to run the laser up the side of the elevator shaft so the car would not obstruct the path of the laser.

You could mount the laser on the bottom of the shaft, essentially on the footings of the building then shine it upward, the motion couldme measured by directing the laser to an array of photodiodes to determine the displacement, to double the displacement of the beam you could place a mirror at the top of the shaft and read the displacement on the ground.

Alternatively, you could use RTK GPS at about \$1-2k for the equipment, with the baseline you have available on a building you should be able to measure centimeter motion.

wwbrown: I wonder if you couldn't do this with lasers set up in elevator shafts? There might be enough clearance to run the laser up the side of the elevator shaft so the car would not obstruct the path of the laser.

Air thermals may cause the beam to wander around. Need an evacuated tube to get reliable data.

I am not sure the turbulence would be much of an issue, if it was I believe it could be removed in signal processing as I think the time constants would be different enough that the signals could be separated. One way to handle it would be to compare the beam at both ends.

The RTK GPS is probably the best method as there would be much less set up and no beam alignment or optical mounting issues.

sears tower does about 6 inches routinely, and over a foot in a storm one world trade center used to sway about 3 feet

Put a laser on a hinged platform at one building wall on the roof. The platform is weighted to stay level when the building sways. Point the laser horizontally at a sensor made of a sequence of photodetectors (IR ?) arranged vertically at the opposite wall, so that if the building sways, the laser beams "climbs" up the sensors. This gives quite a good motion multiplication factor, depending on the extent between laser and sensors, so that very small motions can be detected, and very small effects like air currents will have little influence.

Use two of these at right angles, and you can calculate sway in any direction.

Hi,

The laser pointed down or up the building is a modern variation on old solution. Jack Daniels, in their storage sheds has to keep the multi story facility, that is wooden and over 100 years old, straight as they load it with the barrels. They have drilled about a 1 inch hole in the floors, directly above each other, then run a plum-bob from top to the bottom. The building is straight if the string is in the middle of all the holes. So they load the barrels in according to the string position. I like the laser idea, the longer the distance the more sensitive to motion. Shoot the laser down a piece of poly drain pipe, use a CCD array at the bottom to measure deflecton, do it dynamically and you have velocity and accelleration information.

Tom.... :)

It might not to possible to get a laser beam up through the inside of the building. I'd think the laser idea would work even if the laser were mounted outside the building.

Some sort of camera type sensor could monitor the location of the laser dot on some sort of target.

Parallax sells a rangefinder which uses a camera to monitor the position of a laser dot. I was thinking a similar sensor could monitor the laser dot tracking the building motion.

The laser target is sticking out from the building in my drawing but the target could be on an overhang or even inside the building with the laser shining through a glass window (I'm not sure how well this technique would work with a window between the laser and the target).

The green blob near the laser is a tree. I was thinking it might be possible to hide the laser outside so it's not so noticeable to people passing by.

It might be a good idea have more than one laser and target system on the building in order to track the motion in multiple directions.

Dear Friends,
Point By Point:

1. Many Thanks For Your Helpful Suggestions. The Majority Favours A Laser Device.
2. The Measurement Device is Part of A Innovative Project. Called: Ting Concept House v2.
3. The First Device is For Research. What is The Best Solution (Sensor) For Measuring Movement?
4. See Attachment For Building ‘Type’. (‘Building’ versus ‘System’).
5. At The Left A Drawing of A Classical Building. Monolith (One Thing). Possible Laser Device as Solution.
6. At The Right A System Assembled From Floor To Floor. With ‘Joints’ as Connections.
7. The Future Idea is To Develop All The ‘Joints’ as Sensors and Actuators (Mechatronics).
8. Sensor For Measuring Rotation Of The Joint and ‘Piezo’ Materials as Actuators To Compensate. But This is Future.
9. See Attachment ‘Orientation’: The Data Stream of A Gyroscope (Sense-Hat + Raspberry Pi). The exact measurement of the Angular Rotation in 3 Directions. For Sense-Hat see Attachment.
10. The Sense-Hat is not a ‘Stand-Alone’.
11. Back To My First Post 8-11-2015. To Develop A Stand-Alone Measurement Device (Sensor-Actuator) With Arduino.

Thanks Again For The Dialogue.
Jandirk Van Oosten

Orientation.pdf (176 KB)

What is the budget? Most of the proposals so far are assuming a hobby budget of \$100 or less. This now sounds like a serious project.

Don't forget to use strain gauges in your system house.

Here's the jpg attached to reply #12.

As others have pointed out, attempting to measure distance using a IMU is not easy.

The laser idea came up so often because it would likely be the easiest way to measure displacement.

This sort of thing is done all the time (with accelerometers) in buildings in areas of high seismicity. Google strong motion instrumentation in buildings

Depending on the swing of the building, GPS could be an option?

Another option - create a "triangle maze" between multiple buildings and see the buildings doing "the wave"

Dear Friends,
Point by Point:

1. Thanks Again. You are very Helpful.
2. I Follow The Suggestion of Dave Evans, To Google on the Topic. I Know What To Do.
3. See Attachment: “Gyroscopically Stabilized Building”, By William Chen and Daniel Li. THINK 2014 Winners.
4. XSens 3D Motion Tracking Technology. https://www.xsens.com/
5. I Close This Project.

Thanks Again,
Jandirk Van Oosten