Hi there,

I'm looking for a tilt sensor / circuit that can detect very slight movement, i would imagine a couple of degrees either way, which would intern trigger voltages to an LED array similar to this:

http://img-europe.electrocomponents....R247305-01.jpg

so at level the middle LED's light. Tip the sensor to the right and the right hand LED's light etc.. shall we say and electronic spirit level. Does anyone know if this is possible or are there any purchasable circuit kits out there which would do such a job

Thanks

James

 

The tilt senor itself could be made from a short slightly bent plastic tube with a steel ball in it. On the outside would have to wind two coils side by side that would be part of two oscillators. As the ball moves the frequency of the oscillators would change representing the tilt.
It would be similar to what is called linear displacement transformers.
That is all I have time for..............

 

If you can get an analog voltage out of whatever tilt sensor you chose (have you Googled: Tilt Sensor?), you can use a LM3914 IC to convert the voltage to drive your LED display.

http://www.national.com/ds/LM/LM3914.pdf

You may have add an opamp or two to get the scale and zero adjustable, but it's very do'able.

Ken

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"intern" should be"in turn" (an intern is something completely different, kind of like a student)

THere are electrolytic tilt sensors that do that very accurately (in static conditions), but they cost a lot. Like $300 or so from Spectron Sensor (although the one I have in mind is a 2-axis one). A accelerometer or inclinometer IC would also do the trick.

 

Hi,
From your description of the project it appears that you just require an indication of tilt. Say 2deg either side of the horizontal, not any intermediate degree of tilt. ??

Buy two low cost tilt sensors [look at the Maplin web site] and mount them end to end in such a way that a 2deg tilt to the right closes one and a 2deg tilt down left closes the other.

The switches in the sensors will drive a LED via a limiting resistor.
A little extra logic would light an LED in the mid position.

Do you follow this.?

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I used to do this with mercury switches salvaged from old thermostats. May not be an environmentally friendly thing to do, unless you can be very sure they would not get broken.

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I second the mercury switches.
Always follow the KISS principle.

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The mercury switch method sounds like it could be a goer. I guess its just a case of getting those mountings accurate.

Thanks for all your help

 

Hi all,

a tilt sensor isn't accurate enough. There are lots of acelleration sensors with different resolutions - up to 0.1 degree - on the market (e.g. maxim-ic.com). They are available from one axis to three, to measure X,Y and Z movements or displacements. Interfacing them with a small MCU it's quite easy and cheap to constuct a "spirit level" like it is used in the construction business.

In the meanwhile I will search for a project using a one axis sensor and an LM3914 to indicate tilt.

Regards to all

Hans

 

Mercury switches are banned in the EU.

You can buy non-mercury switches that use a ball bearing though.

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Hi ironside82,

here is what you have been looking for. This circuit uses an ADXL05 (Analog devices). It's obsolete, but probably you can find one - or a suitable substitute.

It is very important for accurate measurements that the longitudional axis is aligned perfectly with the base of your housing.

Here are some pictures.

Hans

 

well, my idea for keeping it simple would be along rolfs lines, with the bent plastic tube and the bearing. but instead of trying to engeneer the wire wraps and oscilators and such, id just put contacts it the tube at the pre-determined locations, and have each contact power the appropriate led.

 

If you haven't got a name for it - I got one: Improved eye ball system

 

Security industry use Inertia sensors, if you can grab one of them from somewhere, it should do the job nicely. Alternately, RS have a sealed stainless steel mercury switch tilt switch?