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  1. hevans1944

    Question about carryover on 4017

    You have the carry output inverted (see Fig 2 - Timing Diagram for CD4017B). The carry output is high for counts 0 through 4, going low on count 5 and staying low during count 9 until the rising edge of the clock sets the counter back to 0. The carry output has to go low sometime before it can...
  2. hevans1944

    An easy relay question for some of you "more experienced".

    It is good, I suppose, that you managed to "fix" the problem by abandoning the Defiant sensors with their DualBrite dusk-to-dawn accent lighting. Who knows how that would work substituting relays for LEDs? Or did your particular model somehow offer dual light levels (low level if no motion...
  3. hevans1944

    Help with IR sensor controlled off-delay dimmer.

    "Better" depends on your design criteria. Simple, inexpensive, and efficient are some you might consider. Form factor (how big it is and where will it fit) is usually a desirable consideration. A 47,000 μF capacitor is likely to take up more space than, say, a Microchip PIC which can perform the...
  4. hevans1944

    Can this wire be soldered?

    We have a recent thread discussion on whether or not you can or should try to solder tinsel wire.
  5. hevans1944

    Complete electronic virgin!

    Have you never had your automobile speed measured with a "radar gun"? Automobile manufacturers are now experimenting with anit-colliision devices based on the same principle.
  6. hevans1944

    Arduino Air flow meter (low speeds)

    We should all keep in mind that Jeroen is a mechanical engineer, not an electrical engineer. While highly competent, imaginative, and willing to learn about electronics, I believe he would prefer an off-the-shelf solution that can either be inexpensively purchased, or modified or built with not...
  7. hevans1944

    Load cell + hx711 = drifting value

    I guess you missed my point. I know how to hook up a load cell, how to provide a balance circuit to zero the load cell output, how to provide a circuit that allows the load cell output to be calibrated, and how to condition the load cell output prior to application to an A/D converter, in this...
  8. hevans1944

    Arduino Air flow meter (low speeds)

    Not so! You could even construct your own hot-wire anemometer. All you have to do is provide a current source to a tiny wire you place in the breeze. And you should also have an identical tiny wire shielded from the breeze, but otherwise in the same environment, excited from another...
  9. hevans1944

    Arduino Air flow meter (low speeds)

    Does all the convective air leave through the rectangular aperture shown in your second photo? What are its dimensions? Do you have an outside ambient air temperature and humidity measurement? Can you use that information in conjunction with the interior temperature and humidity readings (which...
  10. hevans1944

    Load cell + hx711 = drifting value

    And it would immensely helpful if you were to post a complete schematic, including the load cell connections and how you zero-out the load cell and adjust its sensitivity (calibration).
  11. hevans1944

    Complete electronic virgin!

    Microwaves are more reliable. The reflection of laser beams from vehicle surfaces is problematical.
  12. hevans1944

    Sensor for solar irradiance

    What a wonderful effort you and your fellow students are making to improve the life of poor villagers in the mountains of Peru! And you are being way too modest in not mentioning that you are one of the co-founders, along with Dieter Duyck, of the non-profit Humasol. It is amazing that starting...
  13. hevans1944

    Swap out keyboard for 26 push buttons

    Search engines are good. I wish more folks would use them first before posting here.
  14. hevans1944

    simulation is not running in real time due to excessive CPU load

    Why not just build it and see if it works? Simulations are always flawed, and some are seriously flawed, depending on the model and the time increment chosen to run the simulation. If this is for use by a blind person, they won't give a fig whether your simulation works or not. It is the final...
  15. hevans1944

    wanted : 12vdc to 24vac 5 watt schematic

    Many el-cheapo inverter circuits do not provide clean sine waves at a stable frequency. If that doesn't bother you, a simple two-transistor-plus-transformer inverter as suggested in post #8 by @duke37 will do. There are many schematics on the Internet. Here is one place to start looking. You...
  16. hevans1944

    3 phase transformer

    Where did you get this "information"? Here in the USA three-phase power is transmitted to sub-stations with just three high-tension wires: a delta connection. At the sub-station it is transformed to a lower voltage for distribution as a three-phase "Y" or wye. At the end-use point, one or two...
  17. hevans1944

    Simple thing but no idea how.

    And if you don't find a neutral wire inside the switch box, don't you dare use that third-wire safety ground as the return for a small neon lamp that draws insufficient current with, say, a 1/4 watt, 47 kΩ (or higher, up to about 220 kΩ), resister in series with it to trip the GFCI...
  18. hevans1944

    Simple thing but no idea how.

    Almost right. If you connect the light to the hot side of the switch, the light will be on all the time. Instead, connect the light between the load side or the switch and neutral. This adds one more connection to the load side of the switch, the other load connection being the original wire...
  19. hevans1944

    An easy relay question for some of you "more experienced".

    Back in the day (early 1980s) we hired an expert to construct search parameters and search one or more on-line database that charged by the minute. This was way before the World Wide Web and Google existed, but you can still do that. Someone has to pay for all that data warehousing and the...
  20. hevans1944

    Does electron die?

    My wife feeds her kefir with the milk in the back of the Fridge. They grow like crazy! Every day she has to strain off the excess. Her culture has been handed down from generation to generation. Those little buggers could be hundreds of thousands of years old! We make vegetable smoothies out of...
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