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  1. hevans1944

    One button power door locks

    Nice try @Bluejets but the "coil" is two coils if mechanically latched relays are used. You need to steer the pulse applied to the coil to the correct coil, depending on the current position. I really like the center-off toggle (or rocker) switch method. That's the way the door locks on my 2002...
  2. hevans1944

    Timer and Counter and then to LCD

    The 74LS193D can be reset asynchronously, and also loaded asynchronously independent of the "up" or "down" synchronous clock pulses you apply every thirty seconds. Just decode the four counter outputs to either nine or ten (if you want it to stay at the nine count for thirty seconds) and apply...
  3. hevans1944

    Help regarding possibility and planning

    Finding a "reliable, cheap online parts retailer" is a crapshoot. You pays your money and you makes your choices, almost never with a guarantee, although there is some protection provided on Ebay purchases. Caveat emptor (buyer beware) always applies to Internet purchases. I have never tried to...
  4. hevans1944

    building radio control

    Best to buy these ready-made. Even in China you can't make these cheaper than the Chinese manufacturers can.
  5. hevans1944

    Help regarding possibility and planning

    @pusur44017: I like the Russian VFD you have selected. It was once used in an Adafruit clock kit, now discontinued. To save you some time, I have added the Adafruit schematic below: You can also go to this link (http://www.ladyada.net/media/icetube/icetubeschemv1.1.png) to download a fresh...
  6. hevans1944

    Anyone near Indiana?

    I prefer the Underwood Red Devil brand of chicken spread. Probably similar salty taste to Vegemite, but without the B vitamin nutritional benefit. No need to be stingy with Red Devil! Spread it on crackers, thick like peanut butter, pinch your nose shut and enjoy.:D One small zip-top opening can...
  7. hevans1944

    Help regarding possibility and planning

    Pretty nice clock. If you want to build something similar you will need to divide the project into digestible pieces. First thing to do is decide what type of digit display you want: VFD or Nixie. Then find a source for your selection and buy twice as many as you will need for one clock so you...
  8. hevans1944

    How to use water proof ultrasonic sensors?

    Please provide the name of the manufacturer and the part or model number of the waterproof ultrasonic transducers. A datasheet would be helpful. Are these waterproof transducers piezo-electric transducers or magnetostrictive transducers? Magnetostrictive requires much more power and a different...
  9. hevans1944

    One button power door locks

    It has been a while since I experimented with mechanically latched relays but they work exactly as you have shown in your diagram. The only difference is the contacts of the last relay to be actuated stays in the actuated position after power is removed from the coil. You want this to happen but...
  10. hevans1944

    Custom PCB

    See also this thread... which is how I got here. Thanks @Sadlercomfort !
  11. hevans1944

    DC Power Supply Noise?

    I like your chutzpah! A German Tiger, huh? What a great example of German engineering. Good thing we won that war. I liked they way Clint Eastwood faced up to the German Tiger commander in the comedy movie Kelly's Heroes. I think they used Soviet Army T-34 tanks to substitute for the Tiger tanks...
  12. hevans1944

    One button power door locks

    Well, as Homer Simpson would say... DOH!:D
  13. hevans1944

    is electronics a dying hobby?

    Some people once said amateur radio was a dying hobby. After all, you can connect with almost anyone, anywhere, in the world with a cell phone, and not just by voice: two-way "picture phone" conversations are a reality that people enjoy every day. Not that long ago (1968), picture phones and...
  14. hevans1944

    BOSCH reputable car battery manufacturer? then where are datasheets?

    If you want hundreds or thousands of deep discharge/re-charge cycles don't even think about using a car battery or any other lead-acid battery chemistry. Go Google something more appropriate. Maybe a very large capacitor. BTW, I purchased a very nice Bosch hand-held jig saw (what we used to...
  15. hevans1944

    help with voltage reducing, then amplification

    Poor Harry, always under-armed with that pistol when everyone knows a rifle does the job from afar. Sean Connery's character said in the Untouchables to never bring a knife to a gun fight. I say never bring on a fight without overwhelming fire power. Learned that from the results of HIroshima...
  16. hevans1944

    LM317 question.

    You received good replies on the other thread. Just remove all the extra transistors. Leave the remaining base resistors alone. The resistor in series with the voltage regulator is in the right place.
  17. hevans1944

    One button power door locks

    And how does this consume no power when the relay is left energized?
  18. hevans1944

    One button power door locks

    The mechanical latching between the two relays is essential to minimizing power drain. No power at all is consumed until you momentarily energize either one of the two coils. Very old-school, that. But go ahead and learn about active circuits like relay latches, flip-flolps, transistors, etc. I...
  19. hevans1944

    One button power door locks

    I used one of these many years ago. I wasn't sure if they were still made. Mine didn't have a spiffy plastic case. The latching action is entirely mechanical. You energize one coil momentarily and the relay contacts latch to that position. Then when you momentarily energize the other coil, the...
  20. hevans1944

    EEG circuit - need help please!

    @AnalogKid There are many different variations on optical couplers, not just the LED and phototransistor variety. You probably already know this, but maybe don't know the history of optical couplers. One of the earliest versions I used had a neon lamp optically coupled to a light-dependent...
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