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  1. hevans1944

    One Way Communication from Chip-to-Chip

    Well, think of it as an invitation then. Are you up for it?
  2. hevans1944

    One Way Communication from Chip-to-Chip

    The solution he needs is knowledge of how to implement a one-wire serial communication link. The μP he obviously inherited has this capability built-in since it supports the industry standard CAN bus protocol. And there is a ton of documentation on the Web about how to implement a CAN bus...
  3. hevans1944

    What component??

    Is that some sort of three-turn spiral visible under the glass? Could be a resistor. Or maybe an inductor.
  4. hevans1944

    Is my transistor circuit design, selection and maths ok?

    Oops! You are absolutely correct. Bad idea. The inductor would also slow down the LED response to PWM brightness control. Maybe a constant-current source for the PWM modulation, with the off-state current diverted to "ground," would improve efficiency? I just "know" those big stadium LED...
  5. hevans1944

    Changing Signal Frequency And Frequency Overtones Respectively

    Just because you found it on the Internet doesn't necessarily make it so. The sources you cite are not authoritative, they are opinions, just as your statement, quoted below, is an opinion, not a fact. I doubt anyone here would presume that "electrically" is synonymous with "electronically"...
  6. hevans1944

    C program .cpp file encryption

    It is theoretically possible to disassemble an .exe executable, and there are programs available to do so, but AFAIK they all require considerable human interaction to make the results even partly understandable. Unless your program is extremely useful and expensive to purchase (like CAD...
  7. hevans1944

    Changing Signal Frequency And Frequency Overtones Respectively

    Who are you as a newbie, who admittedly "don't know much about electronics," to come here and tell the experts on this forum how to solve your problem? What does it mean to "do this completely electrically?" This whole forum is about how to do things electrically using appropriate technology...
  8. hevans1944

    Is my transistor circuit design, selection and maths ok?

    Page 314 of the datasheet says the output high voltage when sourcing 10 mA could be as low as 2.1 V when Vdd=3V and the chip is operating at an ambient temperature of 105C. So I would consider that "worst case" and lower the NPN base resistor value to (2.1 - 0.7) / 0.05 = 28 Ω. You are well...
  9. hevans1944

    Magnet Alarm Circuit Board, Battery Power

    Yeah, Colin, I was suggesting he cut the traces to the reed switch, solder a pair of wires onto it, and use that circuit to control his fan. Don't even use the circuit board for anything except to hold the reed switch. No batteries needed in the original alarm. He may need an external relay and...
  10. hevans1944

    Is my transistor circuit design, selection and maths ok?

    Also, I would drive all those anodes of the RGB LEDs through separate current-limiting resistors. Presumably, you want 20 mA in each LED (500 mA / 25 LEDs) with the red LEDs dropping 2,4 V while the green and blue drop 3.4 V. So, if your calculations for a single resistor for each group of red...
  11. hevans1944

    Happy Fathers Day!

    We have three Dads here in the house in Virginia Beach where I am "vacationing." So someone went out this morning and bought a box of custom hand-made Duck Donuts to celebrate Father's Day. Unfortunately, someone else had a birthday last Friday and there was one (smallish) piece of chocolate...
  12. hevans1944

    Recycling an old phone/fax machine any ideas?

    A special handshake? Not bloody likely, Mate! I didn't even get a mention, much less a cake and ice cream, when I passed the 1000 post mark. Maybe @davenn will get that when he reaches 10,000 posts. Pleased to offer you a one-finger salute anytime though. Happy posting!:D
  13. hevans1944

    Magnet Alarm Circuit Board, Battery Power

    It sounds to me like the two red wires have some sort of alternating current signal, perhaps superimposed on a direct current "bias" that may be deliberate or inadvertent, when the alarm is sounding. The piezo transducer will not operate on direct current (but a small DC bias won't hurt it...
  14. hevans1944

    More efficient LDR "dark" switch?

    Well, actually, I think Adam used the PIC10F320 instead of the low-power version. I bought the low-power version from Digi-Key and then noticed from the datasheet that the maximum Vdd spec is only 4.0 V for the PIC10LF320 versus 6.0 V for the PIC10F320. So I gotta be careful when I get around to...
  15. hevans1944

    Magnet Alarm Circuit Board, Battery Power

    I am interested in this because a few years ago I purchased some wireless sensors at Lowe's after a burglary at my home. Some were stand-alone sensors with piezo alarms, others broadcast alarms to a G.E. receiving station which also had a piezo alarm. I never did figure out how to get a contact...
  16. hevans1944

    Recycling an old phone/fax machine any ideas?

    Yep, You're right. The Rockwell μP or ASIC or whatever it is on the large "motherboard" is marked © Rockwell 91. Sorry 'bout that @JeanGenie, My bad.
  17. hevans1944

    More efficient LDR "dark" switch?

    This is the chip that Adam used for the Flashlight Project. I have ten of them at home in 8-pin PDIP package that I will use to test Adam's code.
  18. hevans1944

    More efficient LDR "dark" switch?

    I misunderstood. I thought you wanted the LDR to trigger a time delay after it got dark. Why else would you use a 555 timer as a timer, while objecting to using two of them so one could serve as a Schmitt trigger? And why program the PIC with a timer? It has been my experience that both analog...
  19. hevans1944

    More efficient LDR "dark" switch?

    It is certainly possible for digital logic circuits to bite you in the ass, especially if you don't read and understand everything that is important to know... like if you want to use the I/O pins for digital I/O instead of using them as analog comparator inputs, and not knowing they default to...
  20. hevans1944

    Magnet Alarm Circuit Board, Battery Power

    Okay, so you didn't brick it yet. And now you want to replace the three button cells with a 3 V battery and use the 9 V battery (or perhaps two in series) to energize something else, like your 12 V computer fan, perhaps using the reed switch in this device? Is the reed switch the little blue...
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