What would you use to detect a "shaking" motion ?

[jcan]

I am designing a small, "shake-sensing", amusement device. The user will need to shake it back an forth in front of them. The device needs to know if it's moving in one of the two directions, since it will light up differently depending on if it's in the "downstroke" or "upstroke" of a shake.

I am trying to find the simplest and cheapest way to achieve this.

I can across this tilt-sensor on Sparkfun:
https://www.sparkfun.com/products/10313

Does anyone know if this will work, or have a better suggestion?
Thanks!

 

[dougy83]

In line with your "cheapest" link, you can just use a weight on a spring the makes contact with two other conductors when accelerated. Here's an example that I didn't read https://www.instructables.com/id/The-Cube-Of-Curiosity-with-manual-tilt-sensor/

 

[large_ghostman]

an accelerometer would tell you in 3 dimensions which way the movement was and how fast it was moving in those directions, but thats probably not what you need for simple! you could make a simple device.
small tube. each end hot glue small pcb board on with a track cut in the middle, put small ball bearing in tube. the ball bearing touch's both sides of pcb causing it short (switch), so when you shake each time it hits one end or other it will act like a switch for each end. if hat isnt clear let me know I will try and post a drawing

 

[large_ghostman]

sorry posted same time

 

[large_ghostman]

I cant use paint! I will draw what I mean on other pc later

 

[cowboybob]

You're back, LG???

Good to see ya.

Since they have Hg in them the eco-brothers will scream, but an old thermostat Hg switch (3 wire) might be useful.

 

[ronsimpson]

What I have done is:
-Make a cavity in the plastic.
-Put in a steel marble/ball bearing/buckshot/something round and conductive.
-Bring from the inputs of the micro 4 stiff wires into the plastic cavity AND 4 ground wires.
As the marble roles around it shorts out one of the inputs to ground. The micro reads the inputs pins to detect movement and cruddy what direction and tilt.

ALSO

I have used 3 cavities. Long thin cavities running North/South, Up/Down and East/West. Each cavity has a single buck shot. Two input wires from the micro and one ground wire per cavity. Input 1 is on the North end and input 2 on the South end while ground is in the canter.

By looking at the data you can tell something about tilt and movement.
Input North is low, Input South is low, neither input is low. (and has this changed in the last 0.5 seconds)
------------edited---------------
Much like the CowBoy said with a tilt switch from a thermostat.

 

[large_ghostman]

You're back, LG???

Good to see ya.

Since they have Hg in them the eco-brothers will scream, but an old thermostat Hg switch (3 wire) might be useful.

No! strictly speaking, I am allowed to read not post! but I could not resist, my idea is kind of like the others so its now down to how you implement it.
Not sure what punishment dad will give me for posting, but he is laid up for a bit after an accident with the tractor hydraulics, he got his arm crushed

 

[Ian Rogers]

Little Ghostman Please forward my sympathy!!! I hope he mends well...

 

[Mickster]

It would be good to see you back in action LG, but what your Dad says has to be followed as long as you are living under his roof.....like it or not.
However, your Dad comes across as a pretty level-headed and reasonable chap, so there's potential wiggle room if you would like to return, obviously following a frank discussion and you agreeing to stick to terms he allows you to work within.
Please pass on my regards and I hope it's not too serious an injury.

 

[dr pepper]

I rarely did as my dad asked and was allways in trouble for it.
Hope he mends soon.

You can solder a pen spring to a bit of veroboard, solder a weight on the free end of the spring, then just solder a couple of contact pins either side of the spring, with a connection to the spring and another to the contacts the circuit will close when the item is shaken enough to make contact.
Instead of contact pins you could use a piece of metal tube then it would respond in 2 axes.

 

[4pyros]

I can across this tilt-sensor on Sparkfun:
https://www.sparkfun.com/products/10313

Does anyone know if this will work, or have a better suggestion?

I don't know how this sensor works. Has anyone played with it?

 

[Zerotolerance]

I prefer Invensense MPU-6000 series or any of their chips

 

[ronsimpson]

I don't know how this sensor works. Has anyone played with it?

Quoted from SparkFun.com:
-----------------------------------------------------------------------------------
Once in a while something comes out that I think is going to be really awesome, but when you get it, it is just so so. Im sure you all know what I mean… But yeah… This is one of those.

The RPI-1031 available from sparkfun is a pretty simple (heck, it is dead simple) sensor for sensing when it is tilted. And it does this really well. But it seriously only does that. If it is not tilted, it freaks out and reports tilt anyways.

It actually just uses a metal ball that rolls around inside (you can hear it moving around when you tip it). Because of how it is made, the ball is always up against one side even when it is flat. Unfortunately this means you can never know the difference between a reading, and it being flat, only changes in reading.

Hooking it up
This is as simple as it gets I guess. Just power and ground, then connect the 2 digital pins and you are done. These 2 digital pins will output LOW/LOW, LOW/HIGH, HIGH/LOW and HIGH/HIGH depending on the wall it is touching. Again, even if it is flat, it is still touching a wall.

 

[gary350]

A $5 mercury switch.

 

[kubeek]

Ball sensors wil be cheapest, and like ronsimpson noted they only detect change in tilt i.e. shaking, not absoulte tilt.