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  1. gorgon

    Need Help

    I think mine is working ok? :D
  2. gorgon

    Need Help

    All depends on the LEDs you use. You need to look into the data sheet for the different parameters. Absolute max pulsed current is not the same as nominal continuous current, so the datasheet is the answer. This just an estimate: If you use normal small red LEDs with this circuit, you'll...
  3. gorgon

    Need Help

    If the LEDs are 3V you may use 3 in series as in your drawing, but you need at least 15 ohms in series for the 200mA limit. Personally I would start with 150 ohm and look how bright they are with 20mA. You should be aware that red LEDs only drop around 1.7V, and this explains the burnout.
  4. gorgon

    How do you call that?

    We call it cable strips
  5. gorgon

    Multiple pull-down inputs

    If these 'inputs' are configurable in/outputs, you can just configure them as outputs with no pulldowns. Most IO on a MCU can be programmed with a week pullup, so you may leave them unconnected too. This you need to lookup in the datasheet for the MCU.
  6. gorgon

    Resistance Decade box

    10Mohm would be my selection, as long as the switch is up to it. A 0.1 ohm range will normally be used with high currents, normally not supported by a small 'logic' switch as described. A possible problem you may experience, when using high value Mohm resistors are the quality of the...
  7. gorgon

    Why the pull-up resistor is used with debounce buttons?

    I'm sorry to say it, but you need to reeducate your understanding. As said, a pull up or down resistor only predefines the idle level of a digital input, and return the input to this level after activation. You define the lenght of the active level pulse by pressing the push button. When you...
  8. gorgon

    How to start C programming for Embedded (PIC)

    Why not start at the free evaluation version of MPLAB compilers you can find here: http://www.microchip.com/
  9. gorgon

    how to detect laser reflection with photodiodes

    You could do this with two sensor spaced a little apart, looking in the forward direction. You get the 'scanning' by turning the vehicle. The main problem is the type of light you use. If it is visible light you may have a problem with light 'noise' in the room. You may fix that with some form...
  10. gorgon

    Microcontroller pin high when Vcc low.

    You should be aware of the fact that the lowest guaranteed voltage the core will start on is 1.95V. <1.62 V is the highest voltage the core will not start on. You should also think about the use of the battery. No battery likes to be totally discharged, many will not survive it at all...
  11. gorgon

    7-segment display numbers not in order.

    The easiest way I couldthink of, to get a sequence counter values coming out as a string of stacked number would be to use an old EPROM. The ones with windows can be erased and programmed with whatever sequence you need.
  12. gorgon

    Repair TV

    Find the faulty component, buy a new component, change it, and hopfully the TV works again.
  13. gorgon

    lockable knobs

    Is it something like this? http://no.farnell.com/ehc-electronic-hardware/kl901g/knob-lock/dp/1194112
  14. gorgon

    Op Amp - what am I missing

    And the schematics is?
  15. gorgon

    Op Amp - what am I missing

    From the datasheet I can't see that you can use rail to rail input, and certain not output. If your input is centered around 0V you exceed the negative input and run the opamp into whatever domain. You should start with a dual supply and use 0V as ground, including the output. The opamp is not...
  16. gorgon

    multiple displays

    It's no problem to connect devices in serial, it's the number (22) that's the problem.
  17. gorgon

    do I need a circuit?

    Looks like the output capacitor is 220uF and the input capacitor is 470uF on most modules. You should never exceed 1000uF, due to stability. This is general, said on the kgcomp site.
  18. gorgon

    multiple displays

    You could if you made the displays yourself, and used very good quality sensor resistors, but the OP never say he wants to make the displays himself, and most standard shelf displays use a much higher sensor resistance, as mentioned before. That said, most 4-20mA drivers use 24V as drive...
  19. gorgon

    multiple displays

    The main problem you will have is the output voltage of the 4-20mA source. To use 4-20mA on 22 meters you need to place all in series. Each display will drop a number of volts over the internal sensor resistance, and will 'eat' up the available overhead voltage available from the output. The...
  20. gorgon

    What's it called!

    A microswitch should do the job.
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