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DIY audio scope - cheap

Discussion in 'General Electronics Chat' started by flat5, Mar 9, 2015.

  1. debe

    debe Active Member

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    I intend to disable the -5v swichmode & feed from DC to see what happens. Will look for some low ESR caps Tony.
     
  2. flat5

    flat5 Member

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    Certainly worth trying. Good catch.
    Would it help to put .1uf caps across them?
     
  3. flat5

    flat5 Member

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    I decided the diy scope is a toy. Even a 5khz square wave looks quite bad. Chasing the wave up & down the screen, poor syncing at moderately high frequency, even 50khz, the noise.

    Checked this out for a few hours (online) and from the you-tube and honest screen shots I think it will work to a few 100khz.
    Says it's good to 2meg but the 500khz square is not impressive!

    http://www.jyetech.com/Products/LcdScope/e112.php

    http://www.banggood.com/DSO112-2MHz...ital-Mini-Handheld-Oscilloscope-p-977991.html

    Info including manual, schematic & programming here (Edit: also above link)

    http://www.jyetech.com/forum/viewtopic.php?f=17&t=358

    forum, including battery info. Probably does not ship with the battery.

    http://www.jyetech.com/forum/viewforum.php?f=17&sid=035ac91c394519eb1b906df9ddafc61e

    50 Euros
    "sold 1"
    I'm the first sucker, ...I mean buyer.
     
    Last edited: May 20, 2015
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  4. dave

    Dave New Member

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  5. debe

    debe Active Member

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    Removed C23 to disable the switching powersupply & fed 9v dc from a battery to the neg rail regulator. The noise is still there, so I guess the noise is in the opamp. That aside I find it is still a usefull device since it has a read out feature.
     
  6. flat5

    flat5 Member

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    Thanks for the update, debe. I tried to improve a function generator kit last year. No success. The noise problem has to be carefully thought out at the early stages of design. The designers really have to know what they are doing. A simple fix down the road is not going to happen, I believe.
     
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  7. debe

    debe Active Member

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    Apart from its small failings im reasonably happy with the units for what they are. Using Normal its like a crude storage CRO, as I was using it to check the wave form of an IGN module I made to replace point & condencer on a Seagull outboard with a Wico Ign system. Once I had a signal I just disconnected it & had a freeze frame of it. ATOM-WIPAC.JPG
     
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  8. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    It is what it is :D

    The point is it's so incredibly cheap, and fun to build - spec. isn't great, for for the price it's amazing.
     
  9. flat5

    flat5 Member

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    "Scope's got to know it's limitations."
     
  10. flat5

    flat5 Member

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    DSO112 2MHz Touch Screen TFT Digital Mini Handheld Oscilloscope
    first impressions, sent to Banggood as review to get points before 3 other people do the same.

    Only spent an hour with it so far but it will be useful for some jobs.
    First thing I had to cut off the rubber covers on the alligator clips.
    They would not stop slipping.
    I will replace the clips with hooks at least on one cable. (sku065700)
    Connected to a good function generator at 2Mhz the trace is smaller
    and sine, triangle, square waves look the same :).
    At 200khz things are better. Waves are 'better' but the syncing is not stable.
    The noise level is acceptable. This scope is much better than the DSO138.
    Glad I bought it. I have a Rigol DS1052E for more serious work.
    open.jpg with hooks.jpg with wavetek.jpg in case.jpg
     
    Last edited: Jun 16, 2015
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