# Forum: µC & Digital Electronics Foucault pendulum with drive by an electromagnet used as a clock

 Author: Jeremias (Guest) Posted on: 2016-04-18 22:59

Rate this post
 0 ▲ useful ▼ not useful
Hey guys,

I started with a new project.
As the titel already says, it should be a Foucault pendulum
(https://en.m.wikipedia.org/wiki/Foucault_pendulum)
and it should be much smaller than normal.
But because of the fact, that a smaller pendulum means that the
duration of the swing is much shorter, I now wanted to accelerate it by
using an electromagnet.
To control this, I will use an Arduino Uno Board.
This will be no problem for me and others have done this before.
But I also want to read out the angle of the swing to convert it into a
time.
I now wanted to ask you, if you know a trick or a sensor with which I
with as less sensors and the most precision as possible.

Greetings,

Jeremias

 Author: Phil (Guest) Posted on: 2016-04-18 23:25

Rate this post
 0 ▲ useful ▼ not useful
First of all: Electric Parts may be cheap but on the other hand it costs
more engineering - so you should declare whats cheap for you ;-)

My ideas:

Built a gyroscope into bowl.
- Needs wire or wireless solution (weight may manipulate bowl)

Use a cheap Webcam or CCD Chip and Analyse image
- You won't get this to work without an ARM an you need lots of Math

Using photo sensors
-You need a lot of them and light from above. Therefore it's cheap
solution

Hall Sensor / Magnetic field detection
-May work if you have a metal bowl. But difficult to determine direction
and angle cause you have to create / calibrate correlation between Field
/ Angle (Math again)

-Put a pin at the bowl and build a capacitive detection plate

You can also try a vertical solution with components above. But even
there you have a continuous error rate in measurement to interpolate

 Author: clockwork one (Guest) Posted on: 2016-04-19 10:59

Rate this post
 0 ▲ useful ▼ not useful
Put a mirror onto the bottom of the mass of the Pendulum. Place optical
sensors (or camera)under the pendulum which evaluate the direction of
movement by the reflections of the mirror. The optical sensors can also
be used to switch on the drive of the pendulum.

Take as inductive sensor the stator of a 3-Phase motor. By comparing the
voltages in the 3 phases you can evaluate the direction of movement.

Be simple: take a quartz driven clock. Compare its secondpulses with the
pulses of the pendulum-drive. Adjust by the phase-difference the length
of the pendulum synchronizing by this way the crystal clock and the
pendulum.

 Author: restfet (Guest) Posted on: 2016-04-19 11:18

Rate this post
 0 ▲ useful ▼ not useful
Phil wrote:
> Built a gyroscope into bowl.
> - Needs wire or wireless solution (weight may manipulate bowl)
>
> Use a cheap Webcam or CCD Chip and Analyse image
> - You won't get this to work without an ARM an you need lots of Math

Why not go the direct way and use an electronic MEMS gyroscope?

 Author: Joe F. (easylife) Posted on: 2016-04-19 18:33

Rate this post
 0 ▲ useful ▼ not useful
A 2-axis force sensor at the pendulum's gimbal might work.
Could be built using 2 piezo elements.

 Author: Jeremias (Guest) Posted on: 2016-04-19 20:03

Rate this post
 0 ▲ useful ▼ not useful
Thanks guys, your answers helped me really much.
I will think about them and try to find out the one that works best.
If I found anything out, I will inform you.

Greetings,

Jeremias

• $formula (LaTeX syntax)$