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  1. hevans1944

    Looking for eyelets that work for .1" spacing

    NO! Less copper AND spray on the coating to protect the areas without copper.
  2. hevans1944

    Looking for eyelets that work for .1" spacing

    If you have an arbor press with the right dies, brass rivets work well. Set them and then drill them out for through-holes. Or leave them "as is" for point-to-point wiring. And I agree with @chopnhack on the board material. You can purchase blank FR material and then after constructions spray or...
  3. hevans1944

    Looking for eyelets that work for .1" spacing

    Try this web page for sources. They are usually called PCB socket pins, and are available with closed or open ends. You can also purchase ferules for soldering components and the ferules do not contain a socket mechanism, which is probably what you want. Problem is finding the right dimensions...
  4. hevans1944

    Camera Bootstrap circuit

    Well, that's gonna help if those signals are really there (you did say the cellphone was busted). Looks like you have eight bits of digital video, horizontal and vertical sync, a video data clock, and lots of ground returns. There might even be some power available from the phone, unless those...
  5. hevans1944

    Camera Bootstrap circuit

    Probably not,
  6. hevans1944

    Lamp: Will it burn my house down and kill me?

    I didn't mention the ozone producing effect because not very much is produced, and it is diluted by the air flowing past the lamps. It is a big concern if you have any equipment with rubber parts exposed to air with ozone in it. Ozone will attack those parts and render them useless. Don't ask me...
  7. hevans1944

    741 op amp dilemma

    Unfortunately, yes. In the 1970s, early in my career, I once spent an entire working day trying to troubleshoot a complicated op-amp circuit design before discovering the power supply on my workbench was not plugged in.:mad: Do please post a schematic diagram as Alec suggested. And tell us what...
  8. hevans1944

    Please explain circuit

    Since this thread started a discussion of cipher locks, I am seriously thinking about using a microprocessor to build the "random character display with telephone keypad" lock that I described in post #10. I thought it was way cool when I used it sometime in the 1990s. My problem is building the...
  9. hevans1944

    Lamp: Will it burn my house down and kill me?

    Ha ha! Caveat Emptor.
  10. hevans1944

    IR Receptor for Arduino

    Depends on your skill level and whether it contains an infrared sensor. Most remotes (except Bluetooth) use pulse-width modulated infrared transmitters. If you have an oscilloscope you can "see" these "codes" with just about any IR photo-diode. Amplifying and decoding the pulse trains is a whole...
  11. hevans1944

    Lamp: Will it burn my house down and kill me?

    It's designed to fit inside ductwork, so no danger of exposure to germicidal UV wavelengths. The ballast is electronic, so it should run cool. I am considering adding one of these to my HVAC system in Florida. Price is definitely right, but are replacement UV lamps easily available? Unshielded...
  12. hevans1944

    Anyone use this rework station?

    Try this link. Cheaper, and you get four nozzles instead of three. Otherwise appears to be identical.
  13. hevans1944

    Please explain circuit

    You may be right, dorke, but it would take a really fast bouncing switch to make multiple bounces in the interval between the first low-to-high transition of the clock input that advances the counter and the resulting change in the decoded output from logic 1 to logic 0 that removes "power" to...
  14. hevans1944

    Stair Ways light controller

    It sounds like you want something that operates like the radio station selector buttons on a car radio. Press any one button and presto the radio tunes to a particular station and the LED associated with that button comes on. Press another button and the first LED goes off while the radio tunes...
  15. hevans1944

    Please explain circuit

    I agree it is a poor design, but I think it is clever. Probably "gud enuf" to secure an interior door from casual attack if used in conjunction with an alarm that detects unauthorized access attempts. Everyone knows that locks only keep honest people out. A dishonest person with determination...
  16. hevans1944

    Switching Regulator

    I use "smart" batteries. When their output voltage gets too low, the attached circuitry automagically stops working. :p
  17. hevans1944

    Please explain circuit

    The 4017 doesn't get clocked until an output associated with S1, S2, S3, or S4 goes high as a result of previous clocks AND one and only one of the four buttons is pressed. If these four switches are "randomly" placed on the keyboard it is difficult to determine whether one of them will clock...
  18. hevans1944

    Anyone use this rework station?

    I made some tips for my Craftsman heat gun to concentrate the hot air into a small but high-velocity stream. A variable air-flow rate, as this cloned Hakko tool has, would be preferable so the parts don't get blown away. This thing looks adequate for the job, but I have no experience using it...
  19. hevans1944

    Capacitors

    I like this pressurized air-tank analogy better. But remember this: analogy is only an aid to understanding, relying on previously learned concepts to help describe new effects. The new effects, in this case electrical capacitance, are NOT the same effects described by the analogy. The defining...
  20. hevans1944

    Capacitors

    Please visit this website and look around. All of your answers can be found there. You can also jump right in to this page.
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