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Re: Stupid design decisions

From Tim Wescott <seemywebsite@myfooter.really>
Subject Re: Stupid design decisions
Newsgroups comp.arch.embedded
References <o60u6c5ebpdopgrth3flc1vscseb52mshj@4ax.com>
Message-ID <2PKdnS_09-eFkO3FnZ2dnUU7-aWdnZ2d@giganews.com> (permalink)
Date 2017-01-06 15:33 -0600

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On Thu, 05 Jan 2017 21:14:17 -0600, Robert Wessel wrote:

> The following is more a vent than anything really constructive, but...
> 
> So for the last four days (yes, I got called in New Years day
> afternoon), something has been beeping in the computer room.
> 
> Let me rephrase that.  A proper beep would have likely been little more
> than an annoyance.  No, this was a single, fraction of a second, fairly
> high frequency, not very loud, chirp, repeated at odd intervals,
> typically in the 5-20 minute range, although with excursions to the 30s
> and 2-hour-plus ranges.  And did I mention, the volume was not
> particularly consistent?  And it was high enough pitched that half the
> people trying to help couldn't hear it at all.
> 
> IOW, a signal with very poor directionality, in a room with a couple of
> dozen computers, other electronics, A/C, and whatnot contributing tons
> of background noise.
> 
> I have rarely in my life been so frustrated, as I have been trying to
> locate that dang* chirp.
> 
> As it turns out, there was a device that had an embedded fan (1.5 inch
> muffin), and a temperature sensor.  The fan bearing was going bad (in a
> quiet area, removed from the outer enclosure, the bad bearing was
> audible, but not at all in the computer room) and cooling was impacted. 
> The only sign of the overheat was that dang chirp from a little magnetic
> buzzer (an AX-1212-LF, if anyone cares).  Somewhat amusingly, this is a
> device rated for 8-12V, and there's nothing more than 5V headed into the
> portion of the device where the buzzer was (and there are mechanically
> identical 5V and 3V devices in the product line - AX-1205, AX-1203, for
> example).  That probably explains part of both the volume and frequency
> (the device is supposed to be producing ~2300Hz, but it was at least in
> the 5kHz range) issues.  The apparently minimal length of pulse used to
> trigger it likely explains the rest.  And did I mention that this buzzer
> is inside a mostly enclosed component inside the case of the device?
> 
> And no, the overheat does not appear to be reported anywhere (despite
> considerable chat between the device and the host system).
> 
> I understand the need to not make alarms excessively obnoxious (and
> there is a handy little "BUZZER DISABLE" jumper next to the buzzer), but
> making them so hard to hear is just absurd.  Clearly no one ever tried
> listening to this in any real environment.  There are so many ways this
> could have been better.  A simple series of chirps at each alarm would
> have made this infinitely easier to trace.  Perhaps having it repeat at
> a reasonable interval.  Or a reasonable frequency and duration.  They
> went to all this trouble to monitor temperatures, and then have an
> alarm, and then made it almost unusable.
> 
> Took about 15 minutes to swap in a spare (less than half of which was
> screwdriver time).  Now to find a replacement fan to refurb the old
> unit.
> 
> Ah well.  My apologies for the rant.  Back to the regularly scheduled
> program...
> 
> 
> *much stronger word removed

The incorrect voltage spec may have been the brainchild of someone in 
procurement, or of an incompetent component engineer.

-- 

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

I'm looking for work -- see my website!

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Stupid design decisions Robert Wessel <robertwessel2@yahoo.com> - 2017-01-05 21:14 -0600
  Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-01-06 12:27 -0700
  Re: Stupid design decisions rickman <gnuarm@gmail.com> - 2017-01-06 14:51 -0500
  Re: Stupid design decisions Grant Edwards <invalid@invalid.invalid> - 2017-01-06 20:22 +0000
    Re: Stupid design decisions David Brown <david.brown@hesbynett.no> - 2017-01-08 17:11 +0100
      Re: Stupid design decisions rickman <gnuarm@gmail.com> - 2017-01-08 17:10 -0500
        Re: Stupid design decisions Dimiter_Popoff <dp@tgi-sci.com> - 2017-01-09 11:30 +0200
          Re: Stupid design decisions rickman <gnuarm@gmail.com> - 2017-01-09 04:58 -0500
            Re: Stupid design decisions Dimiter_Popoff <dp@tgi-sci.com> - 2017-01-09 13:10 +0200
            Re: Stupid design decisions Clive Arthur <cliveta@nowaytoday.co.uk> - 2017-01-09 11:15 +0000
            Re: Stupid design decisions David Brown <david.brown@hesbynett.no> - 2017-01-09 13:48 +0100
        Re: Stupid design decisions Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-08 17:40 -0500
      Re: Stupid design decisions Robert Wessel <robertwessel2@yahoo.com> - 2017-01-10 21:42 -0600
  Re: Stupid design decisions Tim Wescott <seemywebsite@myfooter.really> - 2017-01-06 15:33 -0600
  Re: Stupid design decisions Ed Prochak <edprochak@gmail.com> - 2017-01-30 12:28 -0800
    Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-01-30 13:52 -0700
      Re: Stupid design decisions Grant Edwards <invalid@invalid.invalid> - 2017-01-30 20:55 +0000
        Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-01-30 14:18 -0700
          Re: Stupid design decisions Grant Edwards <invalid@invalid.invalid> - 2017-01-30 21:20 +0000
            Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-01-30 14:31 -0700
              Re: Stupid design decisions Robert Wessel <robertwessel2@yahoo.com> - 2017-01-30 23:37 -0600
                Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-01-30 23:20 -0700
                Re: Stupid design decisions Ed Prochak <edprochak@gmail.com> - 2017-01-30 22:29 -0800
                Re: Stupid design decisions rickman <gnuarm@gmail.com> - 2017-01-31 02:10 -0500
        Re: Stupid design decisions Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2017-01-30 22:30 +0100
        Re: Stupid design decisions rickman <gnuarm@gmail.com> - 2017-01-31 02:00 -0500
      Re: Stupid design decisions Ed Prochak <edprochak@gmail.com> - 2017-01-30 22:18 -0800
        Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-01-30 23:36 -0700
        Re: Stupid design decisions jladasky@itu.edu - 2017-01-31 16:01 -0800
          Re: Stupid design decisions Paul <paul@pcserviceselectronics.co.uk> - 2017-02-02 09:47 +0000
            Re: Stupid design decisions rickman <gnuarm@gmail.com> - 2017-02-02 06:35 -0500
              Re: Stupid design decisions Robert Wessel <robertwessel2@yahoo.com> - 2017-02-02 16:26 -0600
                Re: Stupid design decisions rickman <gnuarm@gmail.com> - 2017-02-02 19:49 -0500
                Re: Stupid design decisions Robert Wessel <robertwessel2@yahoo.com> - 2017-02-03 01:27 -0600
                Re: Stupid design decisions Les Cargill <lcargill99@comcast.com> - 2017-02-03 07:18 -0600
                Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-02-03 10:14 -0700
                Re: Stupid design decisions Rob Gaddi <rgaddi@highlandtechnology.invalid> - 2017-02-03 10:12 -0800
                Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-02-03 14:10 -0700
                Re: Stupid design decisions Paul <paul@pcserviceselectronics.co.uk> - 2017-02-04 11:15 +0000
                Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-02-04 13:52 -0700
                Re: Stupid design decisions Grant Edwards <invalid@invalid.invalid> - 2017-02-05 04:36 +0000
                Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-02-04 21:55 -0700
                Re: Stupid design decisions Paul <paul@pcserviceselectronics.co.uk> - 2017-02-05 21:39 +0000
                Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-02-05 15:55 -0700
                Re: Stupid design decisions Paul <paul@pcserviceselectronics.co.uk> - 2017-02-05 23:38 +0000
                Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-02-05 21:25 -0700
                Re: Stupid design decisions Les Cargill <lcargill99@comcast.com> - 2017-02-04 17:26 -0600
                Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-02-04 16:56 -0700
                Re: Stupid design decisions Les Cargill <lcargill99@comcast.com> - 2017-02-03 21:40 -0600
                Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-02-03 21:48 -0700
                Re: Stupid design decisions Paul <paul@pcserviceselectronics.co.uk> - 2017-02-04 11:03 +0000
                Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-02-04 13:00 -0700
                Re: Stupid design decisions Robert Wessel <robertwessel2@yahoo.com> - 2017-02-05 01:49 -0600
                Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-02-05 10:43 -0700
                Re: Stupid design decisions Paul <paul@pcserviceselectronics.co.uk> - 2017-02-05 21:31 +0000
                Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-02-05 15:22 -0700
                Re: Stupid design decisions Paul <paul@pcserviceselectronics.co.uk> - 2017-02-05 23:24 +0000
                Re: Stupid design decisions Grant Edwards <invalid@invalid.invalid> - 2017-02-06 03:51 +0000
                Re: Stupid design decisions Paul <paul@pcserviceselectronics.co.uk> - 2017-02-06 10:11 +0000
                Re: Stupid design decisions rickman <gnuarm@gmail.com> - 2017-02-06 20:07 -0500
                Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-02-05 21:08 -0700
                Re: Stupid design decisions mac <acolvin@efunct.com> - 2017-02-04 14:42 +0000
                Re: Stupid design decisions Robert Wessel <robertwessel2@yahoo.com> - 2017-02-05 02:00 -0600
                Re: Stupid design decisions Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-05 09:11 +0000
                Re: Stupid design decisions Robert Wessel <robertwessel2@yahoo.com> - 2017-02-05 03:51 -0600
                Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-02-05 11:10 -0700
                Re: Stupid design decisions Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-05 22:22 +0000
                Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-02-05 16:01 -0700
                Re: Stupid design decisions Don Y <blockedofcourse@foo.invalid> - 2017-02-05 11:03 -0700
    Re: Stupid design decisions Robert Wessel <robertwessel2@yahoo.com> - 2017-01-30 23:44 -0600

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