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  1. BobK

    Wanted$$: Super simple 8 input & 8 output select

    I am not inclinded to do this, because I don't think you really know what you want. First of all, a 1 second scan rate would NOT automatically handle debouncing as you asserted, in fact it would make it possible to completely miss some (maybe even most) button presses. Unless it is your intent...
  2. BobK

    Wanted$$: Super simple 8 input & 8 output select

    What happens when more than one button is pressed? Bob
  3. BobK

    DB25 Parallel Port Programming

    Take a look at this: http://electronics-diy.com/store.php?sel=kits&sub=USB_IO_Board There are others available as well. Search for "USB IO board" Bob
  4. BobK

    automatic switch

    You are going to have to be more specific than that. What are you trying to do? bob
  5. BobK

    Door Latch opener switch

    You will determine that when you pick a solenoid! Bob
  6. BobK

    LED Throwie Safety

    According to this article: http://www.evilmadscientist.com/2009/some-thoughts-on-throwies/ They will last about twice as long (2 days) with a 200 Ohm resistor. Interesting, he measureed 110ma with a new CR2032 and a red LED and no resistor for the first few seconds, declining rapidly. Bob
  7. BobK

    Need a simplest wirless project

    A crystal radio is about as simple as you can get. Bob
  8. BobK

    DC induction?

    And inducutor driven by DC is AKA a resistor. Bob
  9. BobK

    DC Current Draw backs

    1. It is difficult to convert voltages up and down with DC, with AC a transformer can be used. This is important, because when carrying power over a long distance, higher voltage means less current, means less loss. 2. A DC motor (at the time they were deciding on AC vs DC power). Switched...
  10. BobK

    PCB Drilling

    I use a dremel tool. You can get drill bits in the sized needed with an 1/8 in shank that fit very nicely in the dremel. Bob
  11. BobK

    help with a small project - precise 1rpm motor & circut

    No, I am saying that I can't find any such thing. All of the stepper controllers seem to be indended to use with either micro or a PC supplying the speed and direction information. Bob
  12. BobK

    How can I reduce with MOSFET from big DC to small DC

    How much power do you need at 18V? Wikipedia is always a good starting point: http://en.wikipedia.org/wiki/Buck_converter You could use the same MOSFET you have as the switch, but you would have to power the controller logic from a lower voltage. One way to do this is to bootstrap...
  13. BobK

    How can I reduce with MOSFET from big DC to small DC

    That is a linear regulator. Dropping 1000V (or is it 200V?) to 18V will give you an efficiency of 18/1000 = 1.8% at best. And it will needt to dissapate about 1W for each ma of output current. As I said before, you need a buck regulator for any efficieny at all. And that is not a simple...
  14. BobK

    Choosing power supply requirements

    OMG! Bob
  15. BobK

    help with a small project - precise 1rpm motor & circut

    No, you would most likey need to do it every time you use it. The one you reference seems to be adjustable for speed, but not ditially, so it won't be any more accurate than your original design. I also worry that there are descrepancies between the description of the controller and that of...
  16. BobK

    How can I reduce with MOSFET from big DC to small DC

    What circuit did you use? You need a buck converter. Bob
  17. BobK

    FM Stereo

    A breadboard is out. Here is a DIY receiver though: http://electronics-diy.com/electronic_schematic.php?id=12 Bob
  18. BobK

    help with a small project - precise 1rpm motor & circut

    So far, it looks like all of these stepper controllers are intended to be interfaced to a micro or computer. Not much use for the purpose of the OP. What you need is a stepper controller that let's you set the speed digitally (not via a pot), and I can't seem to find anything like that...
  19. BobK

    supply voltage for the sensor

    Do you understand the difference between a switching and linear power supply, and why noise in the power supply is bad when powering a sensor? Bob
  20. BobK

    TDA2005 Amp.

    Have you tried looking at the datasheet? Bob
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