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mini acceleration switch prefer SMT

mini acceleration switch prefer SMT

mini acceleration switch prefer SMT

(OP)
I urgently need to locate a mini acceleration switch for my application.  It will be high volume, 1-5 million in quantity or better when in final production.  It have to be really TINY and light weight.  Packaging is not as critical since we do epoxy coated the entire unit.  The current unit we use used a reed switch.  Due to difficult situation, we cannot use a magnet, and we truly believe the only other way to improve upon and maintain the functionality of  the application is to use acceleration switch that can detect reliably the acceleration (150 fps).  The reed switch we current use is SRC UM23XX. Any one who have info or idea please advice ASAP.

RE: mini acceleration switch prefer SMT

MEMS probably out of question? Or isn't it?

What supply voltage do you have available? Is this acceleration in one direction? Or more axis? What is "tiny"? Like a transistor - or smaller? Or larger?

Do you need a logic signal or a switch that can handle some power? How long is the acceleration period? Some detectors react in microseconds while others need milliseconds. Shal the switch stay activated after acceleration limit is exceeded? Or shall it reset itself?

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: mini acceleration switch prefer SMT

That's about 5Gs, well within the range of many accelerometers.  At those quantitites, I easily imagine a dollar or two for single-axis units.

Dan - Owner
http://www.Hi-TecDesigns.com

RE: mini acceleration switch prefer SMT

(OP)
I understand it is well within range of a lot of acceleration switch.  What is critical is size, weight and power consumption.  The closet I can find is by Star XPF 100 which is right on size and weight. But it is an IC and need power.  The application I want need to be only a switch.  Since it need to in a application for no less than 3 years by the power source alone.  So any power drain will kill the entire app.  the power source for this is a 25mA battery.  the ideal size can be as big as 5mm X 1mm X 2 mm with the direction force along the 5mm.
FYI, Star-M pdf link below

RE: mini acceleration switch prefer SMT

Minor nitpik: fps is a speed. An acceleration would be 'feet per second per second', or 'feet per second squared'.

A switch with a mass would be very simple, but it certainly won't be tiny.

Is this a one-time trigger? Or need to be used many times?

RE: mini acceleration switch prefer SMT

I agree,  Sorry for the typing.  I just not sure what to type on the screen for that square is hard to do.  so 5G switch is what I am looking for.  It need to be really small. MEMS is what I have in mind, but that is not that simple.  So it is not simple or anyone and everyone would have done it.  It has to be a multiple used unit.

RE: mini acceleration switch prefer SMT

VE1BLL, no, nothing to do with that.

Madcow.  That is similar, but I need it to be 25% size of it.  It is way too big for what I need.  It cannot exceed 1.4 mm in height.

RE: mini acceleration switch prefer SMT

You are one tough customer!

Do you need 1/4 of a TO-18 size? I am afraid you will have a very tough time finding that. Especially if you do not want any electronics involved.

You may be able to do something in a PCB - directly from glass-epoxy and Cu. But I doubt if you can get any reliability from such a construct.

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: mini acceleration switch prefer SMT

I only need it to work MOST of the time.  like 80+% would be good enough and low cost.  My entire application including battery is only 1.75" X .24" and it weight less than 1 gram, battery included.

RE: mini acceleration switch prefer SMT

I also find out that MEMS is not the greatest in being a non electronic control switch.  That is why I am looking at other mini mechanical switch.  may be I have to repackage the unit altogether.  But this is worth a try, IMHO.

RE: mini acceleration switch prefer SMT

I suspect you could probably do this with electronics that use less power than your battery does self-discharging.

Does firenock = tinyaccel? I'm confused.

Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com

RE: mini acceleration switch prefer SMT

It is the same.  just that I forget about my password and I send out 4 times with no respond.  So, I just decided to use a new name.  Sorry for the confusion.

RE: mini acceleration switch prefer SMT

For one product I designed, the processor goes to sleep and wakes up every 100ms to check on inputs... I think it used about 60uA, on average.

Dan - Owner
http://www.Hi-TecDesigns.com

RE: mini acceleration switch prefer SMT

ST Microelectronics: P/N LIS202DL

"suits motion-activated user interfaces", "wake-up feature"

5 x 3 x 0.9-mm LGA-14

$3 (10,000)

www.st.com

Source: Mentioned in EDN Oct 25, 2007 on page 84.

RE: mini acceleration switch prefer SMT

Still requires a micro to run, as well as some form of communications channel (I2C/SPI).

Dan - Owner
http://www.Hi-TecDesigns.com

RE: mini acceleration switch prefer SMT

Right. After a quick read, I'd thought that the programmable wake-up function applied to the device itself. But it looks like it needs to be ON (consuming some power) to wake-up the micro. Oh well.

RE: mini acceleration switch prefer SMT

After I talked with a MEMS company, they want something like 100K design fee to start with, then prototype fee, etc.  I think base on the amount and my budget, that is definitely out.  I do think the current package in COMUS have potential.  Do anyone know of another company that may have something smaller?

The volume is not small as you can see.  COMUS ASLS-2 is reasonable small, but I prefer it to be smaller.  Any suggestions?

RE: mini acceleration switch prefer SMT

For even 1 mill units (your lower end), a 100k investment in research is a paltry 10 cent increase in unit price... how tight is your budget?

Dan - Owner
http://www.Hi-TecDesigns.com

RE: mini acceleration switch prefer SMT

Been down that road.

Dan that is just the start.  The down payment.  I would expect the price to be about 5-8x that.

Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com

RE: mini acceleration switch prefer SMT

Inspired by this thread (and some new high-tech toys that I bought recently), I've formulated a new rule-of-thumb:


Designing and manufacturing highly-minaturized high-tech devices is relatively straightforward compared with sourcing suitable highly-minaturized components.

RE: mini acceleration switch prefer SMT

cannot agree more

RE: mini acceleration switch prefer SMT

There are many types of digital pedometers on the market.  They all operate by sensing a slight AC vertical acceleration superimposed onto 1 g DC.  Usually a coiled spring moves a small magnet that hovers over a hall effect xdcr.  For a 5 g application, this concept could probably be miniaturized; have you considered a simple snap action switch with the appropriate seismic mass/spring?

RE: mini acceleration switch prefer SMT

Not yet, but it sure sounded like something I need to look into immediately.

many thank

RE: mini acceleration switch prefer SMT

Have you looked at piezo film? The material is self generating, so only a charge detector might be needed for acceleration level measurement. Here is a Web link:
http://www.meas-spec.com/myMeas/sensors/piezoAccelerometer.asp

They sell packaged accelerometers and piezo material that you could adapt to your own needs.

Walt

RE: mini acceleration switch prefer SMT

Piezo film is a very interesting approach.  the only down side I can see is that it do require IC to make it work.  The space I have do not allow me to have all those and the wight is another significant issue.  Not to mention the power  source which is 25mA battery.  I e-mailed them and see what suggestions they have.  FYI, the entire application is 5 mm diameter X 30 mm length, and weighted 1.2 gram complete with the battery.

RE: mini acceleration switch prefer SMT

Here are a few more extreme micro accelerometers:

http://micromachine.stanford.edu/~kuanlinc/Professional/Mini%20Accelerometer.html
"By utilizing the thin film deposition technique, we fabricated one of the world smallest milli-g resolution, packaged accelerometer.  The size of the whole packaged accelerometer is 500x500x300 µm, giving the weight around 200 nano-gram."

http://www.endevco.com/product/Product.aspx?product_id=20
Low cost/OEM applications
High output efficiency
Light weight (85 mg)
For SMT installation

http://www.silicondesigns.com/Prod.html#SMTaccels
 » Hermetically Sealed, 20 Pin LCC or J-Lead
 » Small Size 0.350"sq. x 0.10"  
 » Light Weight: 0.62 g (0.68g J-Lead)
 » +5V Operation

Walt

RE: mini acceleration switch prefer SMT

Thanks Strong for locating all those Accelerometers.  The only issue is that everyone of them use power.  I need a real switch that do not draw ANY power.  So accelerometers are all but out.  In order to get 5 years shelf life base on a 25mA battery, any power usage is unacceptable.

RE: mini acceleration switch prefer SMT

It sounds like you'll either have to bite the bullet and pay some NRE fees to a company to make one, or bite another bullet and design it in house.  I don't know what kind of repeatability you can achieve, but a single wire inside of a spring with a known (and accurate) lateral spring rate would certainly solve your problem... or give you gray hairs.

Dan - Owner
http://www.Hi-TecDesigns.com

RE: mini acceleration switch prefer SMT

I end up doing both.  Can you believe the difference in price of what is made in US and in China?  The strange thing is that they both use chinese parts.

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