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  1. Old Steve

    Trouble with solder

    I used it once, years ago, and found that. It just didn't flow quite as well. I've stuck to good ol' lead solder ever since.
  2. Old Steve

    Linker files

    You might not need to copy & paste. I think it should work if I'm getting the picture correctly. If your reed switch has a pullup resistor and goes low when the magnet is in place, and if your switch has a pulldown resistor and goes high when it's on, and if the LED is connected between it's...
  3. Old Steve

    Linker files

    I was gonna suggest the CMCON lines, but you've done it. I'll wait........
  4. Old Steve

    pressure measuring device

    That's me on the right:-
  5. Old Steve

    Linker files

    I might have seen something already, but I'll wait until I can see the code properly. Describe the fault a little more clearly, too, if you can please. (A schematic would help heaps as well. Might be a hardware problem.) Does it do absolutely nothing at all? ie No indication that it's even...
  6. Old Steve

    Linker files

    :eek: Assembly. :eek: I'm not really very good with assembly these days. Far too laborious. I work with C or PICBasic in MPLAB. My eyes aren't up to seeing it like that, either. I'll still see if I can spot anything, though, or someone else might also be able to help if it's easier to read. I...
  7. Old Steve

    pressure measuring device

    I've done that, with the grippers on a robotic arm. Not at all practical for weight measurement unless humidity never changes. Minder, the ones you mentioned are fine for really small guys like me, (43kg), but not for the average body weight. Two side-by-side per body might work though. Or...
  8. Old Steve

    PWM led without timer

    Your code throws errors on both _delay_us() lines when I try to compile it. Error 1 __builtin_avr_delay_cycles expects an integer constant. Error 2 __builtin_avr_delay_cycles expects an integer constant. Not that it really matters. I don't need this code. Personally, I'd use a timer...
  9. Old Steve

    Sensor SHT 75 and Arduino Uno

    Good thinking, Adam. I overlooked that possibility. That might throw a CRC error.
  10. Old Steve

    Power Conditioning Unit

    'Isolated' means that there should be no connection between input and output. You'd need to use a switching power supply - switching 28VDC to the primary winding of a transformer at a reasonably high frequency, then rectifying the secondaries to give you DC outputs at the required voltages that...
  11. Old Steve

    pressure measuring device

    As Dave said - a load cell. They're the best way to measure a weight in the range that you want, accurately and consistently. I doubt that you'll find anything comparable, and especially not for $5-$6. There are 100kg load cells here for $5-$10 each:-...
  12. Old Steve

    Sensor SHT 75 and Arduino Uno

    The datasheet says 2.4V | 3.3V | 5.5V, so it shouldn't be the voltage causing the problem. Have you double-checked the pin connections - data on 2, clock on 3? I don't have a sensor to test the code, although it does compile fine with a couple of mods to the libary's *.cpp and *.h file to...
  13. Old Steve

    Help making a CRT oscilloscope

    If I were you, I'd put a 'Wanted' ad in the local paper for an old CRT TV, to use it's horizontal deflection coil as a dummy. You might be surprised how many are still laying around. I can't be the only one. Offer $20 - dead or alive.
  14. Old Steve

    help designing coil

    It's not up to me. You might as well keep the two topics going now. It will mean repeating things from the other one here now, though. Relative inductance is relative to the core, I guess. You don't actually need the definition to use the formula.
  15. Old Steve

    help designing coil

    In the other thread you said you were replacing the horizontal coil. o_O And now you have two threads going asking the same questions.
  16. Old Steve

    My amplifier!

    At least a sound card is cheaper than an amp to replace. ;)
  17. Old Steve

    Need Help!

    And @Louell Gatchalian, a transformer with a 24VAC secondary would be better than 28VAC. With a 24VAC secondary, the rectified DC voltage would be about (24V x 1.4) - 1.2V. (32VDC) That way the LM317 will stay cooler at low output voltages with high current. You'll still need a good heatsink...
  18. Old Steve

    Help making a CRT oscilloscope

    I forgot - the winding wire gauge is a matter of calculation. I went through that bit in an earlier post. It's dependent on the length needed for a given core and the wire's resistance per metre.
  19. Old Steve

    Help making a CRT oscilloscope

    I had to say it. :D And to answer your question - I wish there was a 'shrug' smilie. ;) Trial and error. It has to do with a combination of mass and saturation of the core. Make one, try it while keeping an eye on temperature, and go to a larger core if it gets too hot. You now know as much as...
  20. Old Steve

    Need Help!

    It is possible with a bit of trickery, Rick. Here's a circuit I drew up years ago, for 'Silicon Chip' magazine:- (Takes me back in time- this was 17 years ago.) It won't be as stable as a normal 317 circuit, though. Load regulation suffers slightly - the output will vary a little with varying...
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