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  1. KrisBlueNZ

    Boost solenoid driver circuit

    I was expecting much more current than that. I thought it would be at least a couple of amps. I guess the solenoid doesn't really have to do much though. This is with the fixed voltage drive and just a diode for back-EMF suppression? AFAIK you should have seen a squarewave across the solenoid...
  2. KrisBlueNZ

    Pink noise generator circuit mod

    Pin 9 is one of the VCC inputs to the receiver. Putting a switch there won't do anything useful. There is no input on the receiver that allows you to toggle an output; it's all just controlled from the transmitter. If we use a flip-flop in between the receiver and the noise generator, so you...
  3. KrisBlueNZ

    ST7540 Power Line communication IC

    Hi hayowazzup, welcome to the forums. I haven't used that chip before but I have some general advice. No one can figure out what's wrong with your circuit and/or code if you don't post them. That's not a simple chip to use, both from a hardware point of view and from a software point of...
  4. KrisBlueNZ

    Boost solenoid driver circuit

    It operates at 31 Hz. It's designed to operate at 31 Hz. It just needs a suitable drive signal.
  5. KrisBlueNZ

    Pink noise generator circuit mod

    Yeah, I read that part of the data sheet too, but I don't think it's saying that one button can turn an output on, and another button can turn the same output off. As you say, tech support can answer that question. It might be better to email them; it gives them a chance to pass it on to the...
  6. KrisBlueNZ

    Boost solenoid driver circuit

    It's a start, at least. If you read that article I linked, you'll see that the best solution is a zener in series with a diode, to clamp the spike to a specific voltage above the supply rail. In the example they clamp a 12V relay coil to 24V above VCC. But you get significant power dissipation...
  7. KrisBlueNZ

    Boost solenoid driver circuit

    No, but I may be able to help. Until now, I didn't even know what a boost control solenoid was, and when I read that "The kit includes all the necessary fittings to plumb your wastegate", I started to wonder whether it was something I'd be best to avoid - maybe a euphemism for colostomy surgery...
  8. KrisBlueNZ

    Pink noise generator circuit mod

    Yes, RF Solutions seems to be the answer. The data-only products probably aren't suitable. All we need is a device that can produce a single logic-level output. Ideally it should be controlled so that one button on the transmitter turns the output on (high) and a different button turns if off...
  9. KrisBlueNZ

    Need help getting LCD panel to work

    Well, you've gone to a lot of effort, and you seem pretty keen. I'm not sure this is a good project for a beginner in electronics though. There is a lot of information in the PDF you've linked, but there's still a lot of detail missing. Have a read of my initial response and see what you think...
  10. KrisBlueNZ

    modifying a multimeter

    "resistance of preamplifiers"? Do you mean input resistance? Are these preamps for moving coil cartridges or something? In your case it's probably easiest to apply a known voltage and measure the current, or supply a voltage through a resistor and measure both current and voltage. Here is an...
  11. KrisBlueNZ

    modifying a multimeter

    Your description isn't very clear. Are you saying the current your DMM generates for testing resistance is too high? It might damage the components you're testing? I think it would be crazy to try to muck around inside the multimeter. I would use an external current source, with a suitably low...
  12. KrisBlueNZ

    Pink noise generator circuit mod

    OK, we can try with the J106 and see how it goes. When I buy stuff from them, it comes directly from America, but with the UK being a much bigger market than little old New Zealand, I thought perhaps they'd have stock there, too. You could try Farnell, or whatever they're called now - Element...
  13. KrisBlueNZ

    Pink noise generator circuit mod

    The J310G is available from RS Components, not from Digikey. Are they not ex stock at RS Components either? Digikey UK have three through-hole FETs ex stock - the J106 that you found, and the J111 and J112. The J112 looks like the best option - the J106's graph for gate-source voltage vs...
  14. KrisBlueNZ

    Pink noise generator circuit mod

    You got a schematic? That's great! It doesn't matter that it doesn't show the PCB layout. The component references will all be marked on the PCB. Can you scan it and upload it somewhere, and post the URL here?
  15. KrisBlueNZ

    piezo element

    LOL! A better question might be, should you be allowed to buy it?
  16. KrisBlueNZ

    Is this formula answer correct?

    I suspect the author did his calculations using different values and when he changed them, he forgot to update his answer, or he accidentally plugged the wrong value into the formula. The 398 ohms answer is correct if C2 is 20 pF.
  17. KrisBlueNZ

    need a scrolling led display

    Perhaps I should have said "Programming is required for a PRACTICAL, USABLE scrolling message board"!
  18. KrisBlueNZ

    need a scrolling led display

    That IC is just a serial-input parallel-output LED driver. You need to tell it which LEDs to turn on and off, and you need to implement the scrolling logic. This requires a microcontroller, such as an AVR, PIC, etc, or perhaps a BASIC stamp. Mario's design used a Z80 microprocessor. Programming...
  19. KrisBlueNZ

    Old School Bell

    My guess is it's a telephone bell. If so, it will be designed to run from a 20 Hz sinewave at around 100V. I wouldn't connect it to the mains; the frequency is much too high and it will overheat because the clapper can't move that fast. I'm not sure whether this will help you, but I designed...
  20. KrisBlueNZ

    Pink noise generator circuit mod

    That's OK. All you need is a single SPST contact of some kind, that's open when you don't want the noise, and closed when you do. That's quite a versatile receiver module. It has three normally low logic-level outputs, which I guess have programmable behaviour? You could use one of these...
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