Recent content by Merlin3189

  1. Merlin3189

    What is the name of this kind of connector?

    I think they are generally known as Dupont connectors. You can buy male and female pins and a range of plastic headers, from single pin, 2x1, 4x1, 4x2, and larger. For sizes that you can't get, use a larger one and cut it down. You can polarise them (make them not reversible) by blocking one...
  2. Merlin3189

    Hard Drive Help Needed!

    If you have another identical drive that works, maybe you can swap the control boards., since this is likely where the faults lie. This was possible on old drives, but I haven't dismantled any modern drives and I don't know how they are assembled these days.
  3. Merlin3189

    ARDUINO coding

    I don't know a lot about this and have not used this device nor the MD Parola library, but since no one lese has come in yet, I'll say what I see. I can't see any reason why the display is inverted in the first place. On my reading of the documentation, the display should initialise to normal...
  4. Merlin3189

    Hello can somebody teach me how to connect am to arduino

    If you use a stepper motor to turn the variable capacitor, then the ADC is not needed, as you turn it with the number of steps to get the station you want. (How you find that number is another question.) If you use a PMDC motor to turn it, then you need some way to sense the position. So you...
  5. Merlin3189

    Bare copper wire Question

    Perhaps you could use a PCB lacquer spray, such as Maplin PCB Lacquer or similar.
  6. Merlin3189

    Hello can somebody teach me how to connect am to arduino

    I think heavans has come up with the simple answer to your question. My further thoughts are: Since everyone with an Arduino seems to play with a little stepper motor, have you thought about using a stepper motor to turn the tuning capacitor on the radio? Starting with the idea that you...
  7. Merlin3189

    Pointer dereferencing

    I see AdamSant has given you the answer while I was writing, but fwiw I'll post mine as well. Dereferencing means obtaining the value pointed to by a pointer. You printed out the value of a by using a in the printf statement. But how would you print out that value, if you did not know it was a...
  8. Merlin3189

    Reduce amperage without reducing voltage. Diodes? [Noob]

    Kevin K, I don't think you have the current limiting resistor idea quite right here. You seem to be suggesting a resistor in parallel with the source, to drain off the excess current: 12V 1Amp supply, put 14 Ohm in parallel to draw 12V/14Ohm = 857mA, leaving 1A - 857mA = 143mA for the diode...
  9. Merlin3189

    Motor Discussion

    I know steppers are pretty good these days, but they are still open loop control. Depending on the application of course, I still prefer closing the loop, by adding position encoders whatever sort of motor is used.
  10. Merlin3189

    Signal conditioning for 555 circuit

    Yes, an interesting problem. Maybe something based on a retriggerable monostable with an output of a couple of seconds. This would remain active so long as pulses arrived at least one per monostable period. With the 10 sec pulses it would simply generate a series of elongated pulses. My first...
  11. Merlin3189

    Help with optical sensors

    Have you also looked at the Vishay application note? http://www.vishay.com/docs/80107/80107.pdf This is probably not what you want, as it offers far more information than you want! But the information you want is probably in there somewhere. (If you need more or clearer, try looking for...
  12. Merlin3189

    passive WIFI

    Pretty much agree with all your comments. If this is very short range like RFID, no problem. They just made it sound like the answer to all our wifi problems, which that would not be. Yes ak, I know they didn't claim any specific output power, but if they want to match the performance of even...
  13. Merlin3189

    passive WIFI

    It's hard to tell whether this is bunkum or just something so wrapped up in PR and marketing speak as to be unrecognisable. What I can't understand about it, is what is consuming less power than what to produce what. I believe in physics, particularly energy conservation. So if someone says he...
  14. Merlin3189

    555 PWM or is it?

    Well, I don't know who or what defines PWM, but I looked at this link and I don't think it comes down that clearly in favour of fixed frequency. In 2.6 they say there are 3 types of PWM, all of which are based on a fixed frequency. That might imply they (whoever they are) do think PWM must be...
  15. Merlin3189

    tuned (tank) circuit, oscillator, Q

    Probably not worth reopening this, but I still think the switch is every 90deg. Twice per cycle the current is 0 and twice per cycle the voltage across the cap is 0. Since the voltage is 90deg shifted from the current, that gives 4 energy switches per cycle.. So say we start with a fully...
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