1) Companies usually don't have the time to analyis each incoming request. 2) They know that a certain percentange of people getting the parts will come back for more. They just playing the odds. Even if you don't buy them, you might recomend the parts to someone who does. Steve Faulkner wrote: > I got 2 free samples of the adxl202. Just filled-out the form with perfectly > honest answers - and I was shocked when the next morning I received an > overnight delivery of the 2 chips! > > ----- Original Message ----- > From: "M. Adam Davis" > To: > Sent: Wednesday, January 02, 2002 4:44 PM > Subject: Re: [EE]: I need an accelerometer... > > > Since accelerometers are made using a fairly expensive process (which > > should change over the next few years) you will likely not find one at > > the price range you appear to be after. If you only need one or two, > > you can get free samples from analog and others. > > > > Please note that the adxl202 will only measure up to 2G. It can > > withstand more, but if you need to measure more you should go with the > > adxl210. > > > > -Adam > > > > > > Steve Ruse wrote: > > > > >Precision of .1g would be enough, an extra digit would be a nice bonus, > > >but I wouldn't pay more than a dollar for it. As for frequency, I'm not > > >familiar with accelerometers at all, does that refer to the frequency > > >at which it updates? Does this only apply to the DCM outputs? I would > > >most likely use the analog output. Also, the Analog Devices lists the > > >price of the ADXL202 at $15 and up in quantities of 500+, what > > >distributors carry them? I'd really like to find something more in the > > >sub $4 range. > > > > > >Thanks for the help! > > > > > >Also, sorry about the reply to address, right now I'm away from my > > >computer and using webmail. I changed the reply to address to the > > >piclist address when I sent the message, but apparently it didn't work. > > > > > >Steve > > > > > >----- Original Message ----- > > >From: "Don Hyde" > > >To: > > >Sent: Wednesday, January 02, 2002 2:24 PM > > >Subject: RE: [EE]: I need an accelerometer... > > > > > > > > >>You don't mention anything about the precision you need or the > > >> > > >frequency > > > > > >>range. If you're building an inertial measurement unit for an ICBM, > > >> > > >you > > > > > >>will need a very good and very expensive one (and certain people will > > >> > > >want > > > > > >>to ask you about your project), but for something more ordinary, > > >> > > >there are > > > > > >>some excellent, inexpensive ones available. > > >> > > >>I've used the Analog Devices units on one project. In this case we > > >> > > >needed > > > > > >>+-50g, so the accelerometers were more expensive, in the $30 range, > > >> > > >but the > > > > > >>ADXL202 at +-2g (I think) is only a couple of dollars in quantities. > > >> > > >These > > > > > >>are micromachined silicon devices which are manufactured by processes > > >> > > >quite > > > > > >>similar to IC chip production, and are packaged in the same sort of > > >> > > >packages > > > > > >>as IC's, so they can be handled and soldered just like any IC. The > > >> > > >ADXL202 > > > > > >>even comes in an SMT package that's only about 1/4" square. They are > > >> > > >cheap > > > > > >>because they are used in airbag sensors. > > >> > > >>They output a voltage proportional to acceleration, and can be hooked > > >>directly to a PIC A/D input. They tend to have good accuracy and > > >> > > >response > > > > > >>up to about 1KHz, so they can be used to measure vibrations. If you > > >> > > >don't > > > > > >>want to see the vibrations, then you will need a low-pass filter, > > >> > > >either in > > > > > >>software (easiest is to average a bunch of samples), or in hardware > > >> > > >with > > > > > >>some R's and C's and maybe an op-amp or two. > > >> > > >>>-----Original Message----- > > >>>From: Steve Ruse [mailto:steve@WOTELECTRONICS.COM] > > >>>Sent: Wednesday, January 02, 2002 12:13 PM > > >>>To: PICLIST@MITVMA.MIT.EDU > > >>>Subject: [EE]: I need an accelerometer... > > >>> > > >>> > > >>>I'm looking for an accelerometer, preferable something that is PCB > > >>>mountable. I've never used them before though, so I would like to > > >>> > > >know > > > > > >>>what else is out there. So far everything I've seen is relatively > > >>>expensive (>$25). Any suggestions? > > >>> > > >>>In my application I shouldn't see more than 3-4gs, but it > > >>>will be prone > > >>>to vibration. Do vibrations ever cause problems when you are trying > > >>> > > >to > > > > > >>>make acceleration measurements? > > >>> > > >>>Thanks! > > >>> > > >>>Steve Ruse > > >>> > > > > > >-- > > >http://www.piclist.com hint: PICList Posts must start with ONE topic: > > >[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > > > > > > > > > > > > > > > > > -- > > http://www.piclist.com hint: PICList Posts must start with ONE topic: > > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > > > > > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics