Shop OBEX P1 Docs P2 Docs Learn Events
Prop Success Rate - how long? — Parallax Forums

Prop Success Rate - how long?

HumanoidoHumanoido Posts: 5,770
edited 2010-03-21 04:38 in Propeller 1
The prop is in use for some years now. Can anyone give me an idea of the MTBF - minimum time between failures? I am not interested in data sheet quotes but rather user experiences. How long has your prop lasted and how many hours did you run it without failure?

I started thinking about ENIAC and tube replacement quotes, and began thinking about prop replacement rates, but have no data.

humanoido

Comments

  • Dr_AculaDr_Acula Posts: 5,484
    edited 2010-03-19 09:39
    Gee h, you ask some difficult questions! *grin*

    Ok, I ran three for a week. No problems at all. I think the prop itself is highly reliable and would run for decades - probably till the pins rusted off. But a board is as only as strong as the weakest link, and I suspect the weakest link is electrolytic capacitors. Run them near the limits and, like VGA monitors, I think they will die after 10 to 20 years. You could maybe use tantalums.

    I suspect it will be obsolete before it dies.

    But, consider, you don't want it to last forever. You want it to die! Then the customer buys another one. It is called "inbuilt obsolescence". And how hard would it be to hide some code in there that makes it stop working after a certain amount of time? How do you know other electronic devices don't already do this??

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    www.smarthome.viviti.com/propeller
  • MagIO2MagIO2 Posts: 2,243
    edited 2010-03-19 10:11
    I think the weakest parts are SD card and EEPROM. Of course depending on the application. If you do a lot of writes the chances are high that they fail before the capacitors.

    As long as you don't stress the propeller with overcurrencies/heat I think it will last forever ... at least for your personal forever.
  • John R.John R. Posts: 1,376
    edited 2010-03-19 14:09
    In the category of "who cares", MTBF => Mean (i.e. Average) Time Between Failures.

    As far as "Minimum" time between failures, one can fry a Prop in a couple seconds or less with the (in)appropriate voltage...

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    John R.
    Click here to see my Nomad Build Log

    Post Edited (John R.) : 3/21/2010 4:38:00 AM GMT
  • potatoheadpotatohead Posts: 10,261
    edited 2010-03-19 15:34
    It's entirely appropriate to simply say that for the vast majority of people, the Propeller lasts long enough.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Propeller Wiki: Share the coolness!
    8x8 color 80 Column NTSC Text Object
    Safety Tip: Life is as good as YOU think it is!
  • wjsteelewjsteele Posts: 697
    edited 2010-03-19 15:59
    I've had a prop running continously for over two years now. It's running my "basement protection system." The only time it is down is when the power is out longer than the generator can keep running, which I can only remember happening once.

    I have two sump pumps. If the primary one fails (or can't keep up,) it causes the "water sensor" to trigger on the second pump. When that happens, my generator is primed and started (just to make sure it is ready.) Then the system does a self test (checks to see if the primary sump is running or actually failed.) It also kicks in the backup sump to take over or assist if needed.

    The batteries are topped off (normally they are only at about 75% charge) from the generator. It then shuts down the generator until it's needed. (It primes and starts it everyday as a test when the primary sump detects water.) Otherwise, it just checks it once a week.

    It has alarms for "No Start" and "Low Fuel" conditions. (Low fuel is actually 3/4 of a tank.) It also has alarms for "High Water" and "Critical Water" when the secondary sump detects water (which is 6" above the primary sump) indicating that the primary pump is over worked or has failed.

    This is all due to a flooding problem I had a few years ago when the primary sump failed when the power was knocked out. My recently finished basement was basically destroyed. I put in the second pump and generator to protect against that kind of damage again. (Guess what wasn't covered by insurance, even though I supposedly had "flood insurance!")

    It's all running on a demo board.

    Bill
  • BigFootBigFoot Posts: 259
    edited 2010-03-19 17:06
    We have thousands of propeller biased terminals out in the field and haven't lost one yet.

    Baring a direct lightning strike, I think the propeller chip will outlast most of us [noparse]:)[/noparse]....

    Russ
  • VaatiVaati Posts: 712
    edited 2010-03-19 20:07
    I have had two dead props. smile.gif

    The first one was from last February for the Gadget Gangster Mother's Day contest, and I think it may have been dead when I got it, but it didn't work.

    For my troubles, Parallax gave me a Prop Proto USB board, which I liked very much. Once I got another few DIP props though, I stopped using it as often. When I picked it up again so I could run a program that used the VGA connector, I found that it, too, had gone bad!

    Such misfortune has plagued me throughout my Propeller journey, but they have not prevented me from carrying on! smurf.gif

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Quit buying all those fixed voltage regulators, and·get an Adjustable Power Supply·for your projects!· Includes an LED testing terminal!

    (no longer new) SD Card Adapter·Now available!· Add extra memory to your next Propeller project with ease!

    Post Edited (Vaati) : 3/19/2010 8:14:49 PM GMT
  • Timothy D. SwieterTimothy D. Swieter Posts: 1,613
    edited 2010-03-20 01:17
    I have a several products that have been in the fields and lasted over a year. I believe CustomRinks was designing industrial systems with Propeller I am sure he has some good data on reliability and longevity. With a good system design, the Propeller should work just as well as any other micro controller when comparing life length.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Timothy D. Swieter, E.I.
    www.brilldea.com - Prop Blade, LED Painter, RGB LEDs, 3.0" LCD Composite video display, eProto for SunSPOT
    www.tdswieter.com
  • HumanoidoHumanoido Posts: 5,770
    edited 2010-03-21 02:48
    John R. said...
    In the category of "who cares", MDBF => Mean (i.e. Average) Time Between Failures.
    You mean MTBF?
    John R. said...
    As far as "Minimum" time between failures, one can fry a Prop in a couple seconds or less with the (in)appropriate voltage...
    I was thinking about normal conditions, recommended voltage, no lightning strikes, and not exceeding normal room temperature and humitidy/pressure, not sending it into space with increasing the xray or cosmic ray strike on the chip, etc.

    Overall, it looks like the prop chip has an outstanding report card.

    humanoido
  • John R.John R. Posts: 1,376
    edited 2010-03-21 04:38
    humanoido said...
    John R. said...
    In the category of "who cares", MDBF => Mean (i.e. Average) Time Between Failures.
    You mean MTBF?

    Yep, thanks for catching the typo, I also corrected my original post.
    humanoido said...
    John R. said...
    As far as "Minimum" time between failures, one can fry a Prop in a couple seconds or less with the (in)appropriate voltage...
    I was thinking about normal conditions, recommended voltage, no lightning strikes, and not exceeding normal room temperature and humitidy/pressure, not sending it into space with increasing the xray or cosmic ray strike on the chip, etc.

    Overall, it looks like the prop chip has an outstanding report card.

    humanoido

    I tend to be a smarta?? sometimes. I took the word "minimum" to the extreme. All meant in good fun...

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    John R.
    Click here to see my Nomad Build Log
Sign In or Register to comment.