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Sweat monitor using electrodes.

Discussion in 'General Electronics Discussion' started by JPU, Sep 12, 2012.

  1. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    Oops! That's gotta suck! You weren't fast enough on that one Justin. Ahhh the well water talk'n. :rolleyes:

    Chris
     
  2. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    Some odd things going on here. There were two posts by Justin that are completely gone. One had a link to a YouTube vid that looked good and another with Picaxe code. Both seemingly swallowed up by cyberspace.

    Chris
     
  3. JPU

    JPU

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    1
    May 19, 2012
    Hi chris

    Sorry , I removed them as I have been studying the problem all night and I didn't want to waste anyone's time. I still have a problem but Im just double checking before I repost, that I am asking the right questions. :)

    Justin
     
  4. JPU

    JPU

    281
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    May 19, 2012
    Chris

    Hi, how are you?

    I have been busy feedings babies!

    I wonder if you are still able to help with a TINA problem I have? Its more than likely a simple misunderstanding that I have.

    I have my heart rate monitor schematic that uses 1 opa2134. However when I created the circuit I had to use the symbol shown on the previous schematics to represent the op amp and as a result there are 2 op amps shown on the schematic. When I use TINA to create the gerber files the output, rightly includes the two op amps. The problem is the opa2134 has both op amps built in on one DIP8.

    Do you know how I can create the schematic so that the TINA program allows me to use both amps in the one DIP8 opa2134. I hope you can understand what I mean.

    I have searched the TIna site and contacted technical but no luck yet. Maybe you have a simple explanation of where I am going wrong.

    JPU
     
  5. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    When a chip contains multiples I like to name them with the standard convention of U1A, U1B, etc. Unfortunately Tina will consider that two separate chips when running the PC Board Design. In short they must have the same name IE, U1, U1. After the following steps Tina will rename the second OpAmp on the schematic to indicate that it's 1/2 of U1.

    Follow these steps.

    (1) Double Click each OpAmp and name each one U1 in Properties.
    (2) Double Click on the left most OpAmp to bring up the Properties window.
    (3) Double Click Footprint Name to bring up the Footprint Editor
    (4) Select 8 Pin Dip from the Footprint List box.
    (5) Insure that Parts/Package List Boxes reads: 2 and 1. This means it has 2 parts and this is part 1.
    (6) Repeat 1 through 4 on the second OpAmp.
    (7) Insure that Parts/Package List Boxes read: 2 and 2. This means it has 2 parts and this is part 2. If it isn't, change the rightmost List Box number with the drop down provided.

    FYI: Though I've used Tina for quite some time now, I've never used the PCB Editor until you posted this. ;)

    Cheers,

    Chris
     
    Last edited: Oct 20, 2012
  6. JPU

    JPU

    281
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    May 19, 2012
    Hi Chris

    I have just done that and it works :).

    FYI: My Plessey electrodes arrived to today, so I have some testing to do tomorrow; I could probably do with some help in the next couple of days if your up for it?


    Thanks

    Justin
     
  7. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    I'll be in and out tomorrow but I'll keep my eyes opened.

    Chris
     
  8. JPU

    JPU

    281
    1
    May 19, 2012
    Hi Chris

    The electrodes turned up! and its been disappointment all around. I am beginning to think (know), I am out of my depth here.

    The circuit I have created works well, however the contacts needs to be in direct contact to the skin ie no hair and no movement!!. The picaxe code also worked well and as long as the signal is strong, using the ADC input does work and works well.

    However, once I connected the Plessey electrodes to the circuit, it all goes wrong. The reason I think primarily is that the electrodes are to sensitive for this circuit and also they rely on feedback into the circuit to work.

    As a result I have designed a new schematic incorporating the differential op amp you recommended and some filters the Plessey PDF recommends. The circuit is made up of what I interpret Plessey incorporated into their Demo box and the extra circuit they recommend adding to the Demo box for this application. Here is the circuit I have created but I am yet to test and here is the info from Plessey. If you get a chance your advice would be appreciated but I understand if its to much reading. Do you think I am way off with my schematic and that I should just stop wasting my time!!:confused:,,,,Life?

    (FYI: I couldn't afford the Plessey demo box mentioned as it was $2000:eek:)

    Sensor

    http://dl.dropbox.com/u/7717360/HEART MONITOR/291841 (7).pdf

    Plessey application

    http://dl.dropbox.com/u/7717360/HEART MONITOR/Non-contact ECG measurement using EPIC.pdf

    My Tina circuit, not tested!

    http://dl.dropbox.com/u/7717360/HEART MONITOR/plessey circuit.TSC


    Regards

    JPU
     

    Attached Files:

  9. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    648
    May 8, 2012
    Hello Justin, I just want you to know that I'm not ignoring you. It's just that in between helping out in other topics I've been absorbing the data in the Plessey pdf's and your schematic. When I think I have something informative to say or question to ask I'll post it.

    Chris
     
  10. JPU

    JPU

    281
    1
    May 19, 2012
    Hi Chris

    Thanks for letting me know.

    Justin
     
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