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  1. hevans1944

    Theory of operation of MS3110 high resolution capacitive sensor

    Very sneaky on the part of your "advisor" to make you do the research he should have done as a student. Here is a "real world" fact: Intellectual Property (IP) is valuable but is often stolen. Patents are of some help to protect IP, but only if you have "deep pockets" to pay to defend your IP...
  2. hevans1944

    Theory of operation of MS3110 high resolution capacitive sensor

    @Gryd3: This is a continuation of numerous posts here and elsewhere by @Chengjun Li in an attempt to understand the internals of the Irvine Sensors MS3110 differential capacitance readout. Why he wants to know this makes about as much sense to me as wanting to know how the internal microcode of...
  3. hevans1944

    Confused about a DC Motor

    Sounds to me like your 10 Ω resistor was NOT in series with the 5.1 kΩ resistor. Probably BOTH were in parallel with the motor. So, yes, the motor runs very fast (especially with TWO series-connected Li-ion batteries powering it!) and, yes, the 10 Ω resistor will get hot. Power dissipated by the...
  4. hevans1944

    Confused about a DC Motor

    There seems to be a complete lack of understanding of Ohm's law on the part of @Aro2220. Until that is resolved, I believe further progress is impossible. A permanent-magnet (PM) DC motor with carbon brushes and a commutator is not a linear device. When the rotor is not moving it exhibits a...
  5. hevans1944

    need to determine max power supply current

    @hevans1944 -> If I had a couple of these, I'd be more than willing to just ramp it up until it fails and then I'd know how far I could push the other one. Sadly, this is the only one that I have, though, and I really don't want to risk letting out the magic smoke. That stuff is murder to get...
  6. hevans1944

    Confused about a DC Motor

    Placing a resistor in parallel with the motor should have no effect on motor operation, given the current sourcing capability of a typical Li-ion battery. The OP said the motor quit working with the 10 Ω resistor, so I presume the resistor was inserted in series with the motor in an attempt to...
  7. hevans1944

    Confused about a DC Motor

    You will also probably need to use a high pulse repetition frequency to avoid interfering with the motor commutation. Some experimentation is necessary.
  8. hevans1944

    DC Cable Size question

    It depends on how much resistance 22.9 m of cable has. What the heck is "bi-metal" speaker wire? Copper-clad aluminum perhaps? I would use 18 AWG copper zip cord.
  9. hevans1944

    Confused about a DC Motor

    With the 10Ω resistor in series with the motor and your 3.6 V (ish) Li-ion battery powering it, how much current is drawn? How much current is drawn with two batteries connected in series? How much current does the motor by itself draw when powered from one and then two series-connected...
  10. hevans1944

    HELP needed with part identification PLEASE

    How did you DO that?!
  11. hevans1944

    decoder for 8051

    There are many dimensions to electronics, ranging from the design of microscopic integrated circuits to complex systems with thousands or millions of components. I decided early in my career not to get too involved with the the minutia of circuit design, leaving that to others who did not mind...
  12. hevans1944

    decoder for 8051

    I remember when I got my hands on the Texas Instruments ALU, a TTL LSI integrated circuit sometime in the 1970s. Wow! I could now build a computer! Fortunately, around the same time, Intel started building NMOS microcontrollers so I didn't have to. From the code examples @vead provided, it...
  13. hevans1944

    random signal generator

    An ancient stepping switch with lights wired to it in a "random" sequence comes to mind... IIRC I saw such a contraption demonstrated at a science fair when I was a youth. Impressive with all the incandescent lights "randomly" flashing and the switches clacking. The sound of a stepper switch...
  14. hevans1944

    decoder for 8051

    So what are you trying to do? Build an 8051 from open-source IP? Use an 8051 in a circuit?
  15. hevans1944

    testing capacitors

    Well, you get what you pay for, and you bought a meter that only reads up to 100 μF. The actual capacitance of "large" capacitors is usually not important. What is important is ESR (effective series resistance), leakage current at a specified operating voltage, the operating or working voltage...
  16. hevans1944

    testing capacitors

    An easy way to "guesstimate" the value of large capacitors is to charge them to constant voltage, remove the charging supply, and connect a fixed resistor across the capacitor. The time required for the capacitor to discharge through the resistor to 37% of the charging voltage is equal to one...
  17. hevans1944

    No color in S video - How to convert S video to composite or component?

    I would ditch the Vista laptop and buy a laptop with HDMI video output. Surely the Samsung 32" 1080p has HDMI input? I have a ancient HP laptop that I use when traveling. It runs Windows 7 Professional and has an HDMI output. In the hotel, I hook a 6-foot HDMI cable between the laptop and the...
  18. hevans1944

    need to determine max power supply current

    You might try pulse loading it with a very low duty cycle and low repetition rate, monitoring the output for any sign of sag or fold-back current limiting using an oscilloscope, while increasing the load upwards toward two amperes. Also listen for sounds of distress, overheating, and smoke...
  19. hevans1944

    random signal generator

    I agree that a microcontroller is the logical approach. True randomness is hard to come by, but for HMI (human-machine-interaction) the short-term memory of human beings plays a strong hand in just how random a sequence needs to be to be completely unpredictable by a human. There are software...
  20. hevans1944

    Current regulation for IGBT-based inverters

    Except for transformer type welders (affectionately called "buzz boxes") all modern welders are based on inverter switching technology, typically implemented with IGBTs (insulated-gate bi-polar transistors). The line voltage is rectified to DC and that is used to power the inverter which...
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