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  1. (*steve*)

    i need help with my campus assignments

    Use a passive solar collector to heat air and then pump that (with a small fan) into the clothes (which could be being tumbled, or might just be hung up in some sort of enclosure) See http://www.solarsponge.com/
  2. (*steve*)

    Retrofit house with LEDs

    I've characterized a number of 12V LED bulbs for my own nefarious purposes and I have found that they may have inbuilt buck or boost regulators. Those with boost regulators have an unfortunate failure mode when the input voltage rises too high. Depending on what that voltage is, if they have...
  3. (*steve*)

    Electronic Circuit error

    According to your layout shown in your first post you have not shown us the whole circuit here. We should be able to see 7 positions to the left of the IC, but we can only see 4.
  4. (*steve*)

    Electronic Circuit error

    That image is a bit out of focus, but it is clear that your soldering is a bit rough. It looks like you may have some shorts across strips, and some joints may not be making contact. Are the strips 4th and 5th from the bottom shorted together?
  5. (*steve*)

    Electronic Circuit error

    They would be the parts labelled as D1 and Q1 on the schematic you've provided to us.
  6. (*steve*)

    Unable to get solenoid controlled by Arduino to work anymore

    If you used this without a diode, then yes. However I would not expect it to have failed with all pins open. Are you sure you were trying on a resistance range?
  7. (*steve*)

    garage door opener

    Did you correct this before you applied power?
  8. (*steve*)

    Capacitance on PIC I/O line

    No, it is a feature of capacitors
  9. (*steve*)

    Unable to get solenoid controlled by Arduino to work anymore

    Which pin is base, emitter and collector is best determined by looking at it's datasheet. The middle pin is frequently NOT the base. If you're lazy, the collector is connected to the tab of a TO220 transistor. The emitter will show a high resistance (or open) with the multimeter probes either...
  10. (*steve*)

    Capacitance on PIC I/O line

    Capacitance on the I/O lines will affect rise and fall times, and eventually the maximum frequency. It has nothing to do with bypass capacitors. Minimising the length of I/O lines will keep parasitic capacitance and inductance low.
  11. (*steve*)

    Measure distance to water surface

    Aaaagh @Fish4Fun... I also thought of measuring the depth of the water via a pressure sensor and using that to calculate the position of the surface. I'm glad you provided a link to a pressure transducer.
  12. (*steve*)

    Small low-power light sensor

    Try replacing the LDR and see if that fixes it. You would get that fault if the LDR is open.
  13. (*steve*)

    garage door opener

    Sorry about that... That eliminates much of what is in the replaced box as a cause of the problem too.
  14. (*steve*)

    garage door opener

    Does the unit have a switch to allow you to open/close the door? Does this work?
  15. (*steve*)

    Modifying 4.5 V (alkaline) lamp to run brighter with 3.6 V (NiMH)

    Use a number of lithium cells in parallel with a buck regulator. Find one that has a low voltage cutout.
  16. (*steve*)

    Modifying 4.5 V (alkaline) lamp to run brighter with 3.6 V (NiMH)

    Use 4 NiMH batteries.
  17. (*steve*)

    Electronic Circuit error

    The other side of the board would be good. That way we can see what you've actually done. Please don't use the flash on your camera.
  18. (*steve*)

    PWM setup

    Yes it matters a great deal. If you need multiple strings in parallel then you'll need to ensure the current is equally shared. A resistor in each string will help. Something that drops a couple of volts should be sufficient. 2W 6.8Ω resistors should work fine (they will drop 2.4V at 350mA)...
  19. (*steve*)

    Do SMD resistors fail open after some time?

    I would be curious about whether you've tried measuring the resistors after you've removed them. If it's a problem with the solder joints fracturing, the resistor may read ok. However it's also possible (maybe) that the fracture has pulled off the contract at the end of the resistor. I would...
  20. (*steve*)

    PWM setup

    Great, you have a meter Now measure the forward voltage of each different type of LED. Also, don't put the LEDs in parallel. Odd things can happen.
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