Connect with us

MIller Solar Engine 1381 replacement?

Discussion in 'General Electronics Discussion' started by kaczchris, Aug 13, 2013.

  1. kaczchris

    kaczchris

    12
    0
    Aug 13, 2013
    I know BEAM robotics have fallen out of style a bit, but I hope someone is still mucking about with them because they are super cool. And if you don’t know what I am talking about check it out!

    Right now I am working on a Miller Solar Engine and trying to find a replacement for the 1381-J voltage trigger. I tried out the DS1817. It was recommended to me by one of the technicians at Digi-Key as a replacement for the MN1381-J and on paper it looks like a good swap, but in the circuit it is just not resetting once the voltage drops. I have it breadboarded and I can stick the 1381 in it and it works perfectly. When swapped with the DS1817 it triggers once the top voltage is reached, but then never resets (it just drains forever.) I double-checked the component type to make sure it was just not a miss shipment of the wrong item, but it checks out. And I tried swapping the DS1817 component out thinking that I just had a dud (or 5) but it does not seem to help. :confused:

    Any thoughts?

    Here are the data sheets on the 2 items.
    http://datasheets.maximintegrated.com/en/ds/DS1817.pdf
    http://www.semicon.panasonic.co.jp/ds4/SAG00003CEM_discon.pdf

    one bit of weirdness I already figured out is that the 1381 looks like it has a different 1-2-3 pin out sequence at the top of the PDF but it turns out it does not at the bottom. (just flipping the new component does not fix it)

    Here is a link to a miller engine schematic:
    http://www.beam-wiki.org/wiki/Miller_Solar_Engine

    Thanks for your help!
    :)
     
  2. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

    4,960
    648
    May 8, 2012
    Quite frankly it blows my mind that a circuit that basic, that's based on an off the shelf chip, was named after the guy! By the way, there's a discrete version of it. In both cases they amount to a relaxation oscillator.

    Chris
     
  3. kaczchris

    kaczchris

    12
    0
    Aug 13, 2013
    A discrete version of it?
    forgive me as I do not know exactly what you mean by that.
    Are you referring to the part swap or the whole circuit?
    Thanks.
     
  4. davenn

    davenn Moderator

    13,351
    1,774
    Sep 5, 2009
    discrete = individual transistors etc .... no IC's


    Dave
     
  5. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

    4,960
    648
    May 8, 2012
    Yes, as Dave explained. The path to the topic is on the schematic.

    Chris
     

    Attached Files:

  6. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,219
    2,695
    Jan 21, 2010
    There are many "voltage detector" devices out there which could be used.

    You need one with some hysteresis or where this can be somehow finessed into the circuit.

    It looks like most of the web pages are down :-( Many were last updated over 10 years ago...

    Have you looked for the sites in the internet archive?

    This site used to have lots of schematics, but now all I get are blank pages.

    Even the internet archive doesn't help...
     
  7. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

    4,960
    648
    May 8, 2012
  8. kaczchris

    kaczchris

    12
    0
    Aug 13, 2013
    Thanks all for the good comments, I had actually searched and found the thread linked but did not find it fit what I am trying to do. The BEAM circuit is more than just a functional thing, it is also about the simplicity, elegance and efficiency of the design. The Miller engine is distinctive because of its small number of components and its efficiency (in fact with the setup i am using i do not even need the resistor so there is no energy loss to resistance at all.) Playing with such small bursts of electricity makes efficiency really important.

    I think that the crux of the problem has been defined, I am looking for a voltage detector that will replace the discontinued 1381 with sufficient hysteresis to use in the relaxation oscillator called the Miller engine. I had thought I had found it with the DS1817, but for some reason that is beyond me it is not working. Any idea on why that component is not working (or of a more suitable replacement for the 1381?)
     
  9. kaczchris

    kaczchris

    12
    0
    Aug 13, 2013
    And yes, many of the BEAM pages are unfortunately fallow.

    there was a lot of interest years ago, but i think the limits were quickly reached by many.
    That being said there is still a lot of awesomeness that can be done with the circuit. the challenge becomes an engineering one where you have to translate this little tiny burst of energy into something interesting.

    For reference here is a link to one of my projects using the Miller engine:
     
  10. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

    4,960
    648
    May 8, 2012
    That will revolutionize the world as we know it. Please make mine sunny side up and easy. Does it come with bacon and grits?

    Chris
     
  11. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,219
    2,695
    Jan 21, 2010
    There's a false statement :)

    Just because you don't have a resistor doesn't mean there's no resistance.
     
  12. kaczchris

    kaczchris

    12
    0
    Aug 13, 2013
    true. sorry if you thought i was saying there was no resistance in the circuit.
    just not using a resistor which just "wastes" energy for heat in the grand scheme of things.
    :)
     
  13. kaczchris

    kaczchris

    12
    0
    Aug 13, 2013
    no bacon and grits yet.
    but pancakes yes!


    :)
     
  14. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,219
    2,695
    Jan 21, 2010
    However a base resistor can save energy by limiting base current to the required value.

    Excessive base current is at a minimum a waste, and at worst will damage the transistor.

    It's not as simple as you might think...
     
  15. kaczchris

    kaczchris

    12
    0
    Aug 13, 2013

    it never is.
    :)

    thus my problem with figuring out the "why does it not work" with the DS1817...
    :eek:
     
  16. kaczchris

    kaczchris

    12
    0
    Aug 13, 2013
  17. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

    4,960
    648
    May 8, 2012
    Have you compared the data sheets between the two?

    Chris
     
  18. kaczchris

    kaczchris

    12
    0
    Aug 13, 2013
    to my limited ability I have compared them. (first thing I did)
    I got the suggestion for the swap from a digi-key technician who I hope knows more than my limited electronics knowledge.

    A friend of mine has mentioned that the 1381 is CMOS and the DS1817 is TTL, do you think that might be causing different behavior?
     
  19. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

    4,960
    648
    May 8, 2012
    The 138(n) series come with 1 of 3 output variations. CMOS(Push-Pull), NCHAN(Open Drain) and Inverted CMOS(Push-Pull).

    The DS1817 is provided with CMOS Push-Pull output only. Typical output current appears to be about 350uA.

    Is your circuit like this with the PNP eliminated?

    http://www.solarbotics.net/library/circuits/se_t1_mse.html

    Chris
     
  20. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

    4,960
    648
    May 8, 2012
    After comparing the data sheet waveforms between the 1381 and the DS1817 I now see what your problem is. As is (no additional circuitry) the DS1817 will not replace the 1381. There is nothing in your circuit to turn it off after it's triggered.

    Chris
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-