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Thread: Op Amp choice

  1. #21
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    Re: Op Amp choice

    Quote Originally Posted by Igor P  View Original Post
    if I understand correct you use direct readings from ADC in your project, is this correct?

    Yes.

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    Re: Re: Op Amp choice

    Quote Originally Posted by cys  View Original Post
    Yes.
    Ok, thanks...

    Sent from my PAP4500DUO using Tapatalk 2

  3. #23
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    Re: Re: Op Amp choice

    Quote Originally Posted by nicklinux  View Original Post
    Interesting, I've been using arduinos 10 bit adc with terrible results.. Don't know if it's coz layout of the board or long distance between controller board and cell or something else..
    Let me ask you this, do you have a lot of noise during sampling with this chip? I would guess you use delta readings per second for function return to minimize these fluctuations.


    Sent from my MK15 using electronics pod.
    10 bit is not enought for the job without OPA (sensor readout). The resolution is too low.

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    Re: Op Amp choice

    Hi Nick, glad to see you pop in, thanks for all your support over the last couple of months.
    I've had my mini pro displaying ADC values, converted to mV and converted to PPo2. I have used my cell simulator and just a 10k pot (depending if I'm at work or home)all on the serial monitor.
    I've machined up an acrylic housing with button on one end, but not started the electronic pod yet as in not sure how I'm going make my board yet.
    I was hoping to supply the mini pro with a 7.4 or 11v lipo battery (on raw pin) then using the mini's vcc to supply op amp.
    On your board you used a v.reg for mini pro and another for op amp? Can you seen any issues with running the amp from the vcc of the mini pro? Remember I'm only monitoring the cells, no control of sol etc.
    Regards
    Baz

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    Re: Op Amp choice

    Hi all,
    Just to let you all know I've ordered a mcp6034, the spec's looked good and I was able to add some to a recent order I was making at work

    Many thanks to all who contributed

    Regards

    Baz.

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    Op Amp choice

    Hi Baz, you're welcome !
    You can power your opamp through Vcc pin and use onboard regulator with power on row pin.. I just build off board voltage reg and powered Arduino thru Vcc pin.


    Sent from my MK15 using electronics pod.

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    Re: Op Amp choice

    Thanks Nick,

    Did you notice the mcp6034 was a surface mount chip! Since I started this thread I've been watching some YouTube's, and they make it look sooooo easy.....I'm sure its not but ha ho I'm up for giving most things a try.

    I hope this will help others out too as when I starteds looking up op amps there were lots of people saying they used them but no part numbers etc, so now if someone searches op amps they'll get a few to look at and the high res adc's too. Was kind of hoping Greg (packhorse) might have poped up his one button menu looked sweet.

    Regards

    Baz

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    Re: Re: Op Amp choice

    Quote Originally Posted by turtle dude  View Original Post
    Thanks Nick,

    Did you notice the mcp6034 was a surface mount chip! Since I started this thread I've been watching some YouTube's, and they make it look sooooo easy.....I'm sure its not but ha ho I'm up for giving most things a try.

    I hope this will help others out too as when I starteds looking up op amps there were lots of people saying they used them but no part numbers etc, so now if someone searches op amps they'll get a few to look at and the high res adc's too. Was kind of hoping Greg (packhorse) might have poped up his one button menu looked sweet.

    Regards

    Baz
    Hi mabe I can help a bit. I used in my project one of his electronics.
    I put on it my own version of software that works as a live CCR decompression computer with HUD and ppo2 monitoring.

    MCP6004 is PDIP version of OPA.

    Igor P

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    Last edited by Igor P; 27th September 2014 at 18:36.

  9. #29
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    Re: Op Amp choice

    Hi Igor p,
    I would like that very much,
    I'll do a couple of sketches of what I'm up to and pm you if that's OK.

    I decided to go with a surface mount chip as I'd read they were better for battery operated equipment and that pdips can suffer from bad connection on the sockets and then draw more power? Weather that's completely true? But with the type of environment its going in, thought I'd give SM a go.

    Regards

    Baz

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    Re: Op Amp choice

    Had some time so i made a "proof of concept" of design/parts selection for the next ccr monitor AFE. The digital part is not very impressive, as a proof it is done on Arduino Mini Pro. The analog uses TLC4501 as the preamp for the cell and ADS1110 as the ADC. On tha bottom side of the green PCB is DC/DC converter that makes 5V from 3.3V for the preamp (charge pump) and MPL3115 for ambient pressure and temperature (this part will not be in the monitor, it will be used in the handheld oxygen analyser).
    Everything works like a charm, only the ADC has a slight offset, but i think that i will make some autocalibration to compensate this.
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