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  1. CDRIVE

    Sweat monitor using electrodes.

    Justin, I just emailed my niece, who's been raising horses since she was knee high to a grasshopper. If there is any way possible to duplicate the finger tip Optocoupler concept on a horse, I want to know about it. It would solve the noise issue. Yes, I'll continue to tutor you. We'll talk...
  2. CDRIVE

    Ohm's Law or not Ohm's Law... That is the question

    Yes it has but in the end it will probably never be unanimously resolved. It will probably fall into the category of "We agree to disagree.". :) Chris
  3. CDRIVE

    Valve (tube) amplifier schematic help

    Yes, it feeds the input of a 386. I modeled that circuit to provide a wide audio bandpass into a 10K load. I think the 386 has an input impedance of about 50K but I'm not certain. If the input of the 386 is 50K then C2 can, but doesn't have to be, reduced to a disk cap of .2uF. Chris
  4. CDRIVE

    Sweat monitor using electrodes.

    I think this is more pertinent to your project, as heart rate is far less complex than EKG. http://en.wikipedia.org/wiki/Heart_rate_monitor Chris
  5. CDRIVE

    Sweat monitor using electrodes.

    Some heavy reading here. http://en.wikipedia.org/wiki/EKG Chris
  6. CDRIVE

    Sweat monitor using electrodes.

    Unfortunately I can't confirm that EKGs work as you describe, only that OpAmps can be operated as I described. Whether any of the EKG leads are actually earth ground, circuit ground or ground at all, I don't know. For certain, when connected to the body, things get extremely messy. One thing I...
  7. CDRIVE

    Electronic timer question

    I think that was a brain fart on my part. I was hoping the OP would post the existing circuit. Chris
  8. CDRIVE

    Sweat monitor using electrodes.

    Look what I just received in my inbox from one of my suppliers. http://www.saelig.com/product/SEE011.htm?utm_source=October+2012+Newsletter+%28A%29&utm_campaign=Saelig+Newsletter%28A%29++-+Sep+2012&utm_medium=email Heading out to the well. See ya later. Chris
  9. CDRIVE

    Sweat monitor using electrodes.

    Yes, we've finally arrived at the purpose of this exercise. OpAmps have two inputs. Inverting and Non-Inverting, which is why they're differential amplifiers. Your noise generators are hooked up in Differential Mode. If two input signals, noise in our case, are of the same amplitude, frequency...
  10. CDRIVE

    Sweat monitor using electrodes.

    Justin, I forgot to mention that my wife and I are having a few drinks and dinner with my buddy Ron today. When I first started contracting at the hospital Ron was the Bio-Med Electronics supervisor. I will be picking his brain regarding ECG's/EKG's. I do know that our EKG's were tested and...
  11. CDRIVE

    Sweat monitor using electrodes.

    OK, "next bit". Since you now have Vnoise2 turned on, what does your signal to noise ratio look like on the OpAmp's (VF1) Output? In other words, do you see any noise there? Chris
  12. CDRIVE

    Problems substituting a relay

    JB Weld is handy stuff. They make different blends of this product, one of which contains aluminum particulates. The stuff is easy to work with and is high temp tolerant. If you have room in your enclosure you can use it to bond an aluminum heat sink to the Zener. If the enclosure has a metal...
  13. CDRIVE

    Sweat monitor using electrodes.

    You're still not getting the point of this exercise. At this point you shouldn't see Noise2 because it's set to OFF in its properties. The purpose of this simulation is to show how unwanted noise can modulate a wanted signal that we're amplifying. Before we move on do you understand this? Chris
  14. CDRIVE

    Sweat monitor using electrodes.

    Yes, electronics is an exact Sinus. You can separate the plot curves by clicking View - Separate Curves on the tool bar in the plot window. Let me know that you did it and we'll do the next step. Chris
  15. CDRIVE

    Sweat monitor using electrodes.

    I see it and you did it again!!!!!!!!!!!!! Look at the value of R1. Chris
  16. CDRIVE

    Sweat monitor using electrodes.

    Not sure. I'll have to check your TSC. file again. I hope you didn't blow the chip! What version of Tina do you have? Chris
  17. CDRIVE

    Sweat monitor using electrodes.

    Actually, the Pro version of Tina includes a quasi virtual smoke test but the cost difference between Tina Classic and Tina Pro is known to induce heart attacks. Chris
  18. CDRIVE

    Chronograph for bullets

    From strictly a reliability standpoint; that's why I prefer wheel guns. ;)
  19. CDRIVE

    Sweat monitor using electrodes.

    It's no wonder you're having problems. You have the Transit Time set from 0 to 50M. That's 50 Million Seconds! It should be 50m. You made the same mistake on the AC voltage setting for Vsig. 'M' = Meg or Million while 'm' = milli or millionths. Lastly, if you use voltage pins for the...
  20. CDRIVE

    Sweat monitor using electrodes.

    Let's start by discussing the OPA134 spice sim. Did you run a Transit plot? If so, do you understand the results? Chris
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