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  1. Externet

    circuit design

    Start with the basics; an electronics experimenter kit or development kit at the expertise level you need will have a decent theory booklet with it, and ther is dedicated specialties for power management, digital, analog, embedded...
  2. Externet

    Looking for an RC Transmitter & Receiver

    Just swallow the pill. Buy a RC toy that suits your wishes; dismantle it to pieces while making a schematic of everything. Now you have ALL the parts needed for your project at an unbeatable price and no need to spend a year looking/gathering for parts vendors or unobtanium. Ahh... Will be...
  3. Externet

    help needed

    A fax machine detects the presence of paper in its feed path by using an optocoupler. Installing one of those optocouplers in each pipe will be able to flash a led off (or on) when the tube is blocked or a seed is passing or present . They look like...
  4. Externet

    Voltage detecting switch

    Cotsey : PSTN will always have 50V DC when not in use. Will have anywhere from 3 to 12 VDC when seized. So do not need to detect it; it is always there. If you want to know if the line is active instead of 'dead' or disconnected; connect a LED observing proper polarity directly to the telco...
  5. Externet

    How to wire a 12V DC set of CCFL lights, into my car audio system

    Hi. Am unable to post diagrams. Done it a dozen times to play with and show kids. You would have to learn what a bridge rectifier is : http://www.gotwind.org/diy/images/Bridge_Rectifier.jpg OR: http://www.p-wholesale.com/upimg/5/296a1/bridge-rectifiers-gbu808g-670.jpg Like RadioShack part...
  6. Externet

    How to wire a 12V DC set of CCFL lights, into my car audio system

    Connect the output of the audio amplifier to a full rectifier diode bridge and feed the lamp with that, observing polarity. If the audio signal will be very loud, insert a resistor in series choosing the proper value that at full volume will not produce more than 12 VDC.
  7. Externet

    Wanted: CD22204 or MC145436 ICs

    Found the CD22204s. Forget it and thanks.
  8. Externet

    Need Help! About the LED light.

    Seems to me that R2 and R3 values are swapped. C8821 400V224J The capacitor code means manufactured the 21st week of 1988; 400 volts, 220nanofarads; 5% tolerance
  9. Externet

    Good SOund

    Good sound is the one closest to the original performance. Good music is the one that pleases hearing and feelings the best.
  10. Externet

    AC rectification for LED's help

    You do not need a bridge rectifier. Connect 2 series leds in counterparallel to another 2 series leds; fed current limited by a small resistor. Perhaps ~100 Ohms? AC-------------Y------------|>|--------|>|---------------X-------\/\/\/\/\/\-------------AC...
  11. Externet

    Going from prototype to production question.

    National Semiconductor LM556 are available also on package M14A for surface mount.
  12. Externet

    Piezo electricity

    Piezoelectric material would be destroyed instantly under a passing vehicle. But you can still try. Check this : http://www.ecnmag.com/products/2010/06/IC/Energy-Harvesting-IC.aspx At the end is a data sheet link.
  13. Externet

    need help with project

    Shine a secure held laser pointer to a solidly mounted mirror at the gate/laneway and a photodiode sensor back at the base bounced point. No power supply that can fail/tampered requiered at the gate, Falling leaves/animals could trigger the beam but take them as functional system self-test ...
  14. Externet

    16 x 2 lcd question

    The project should had said Hitachi "HD44780 based LCD" instead of the way expressed. It is the most commonly used chip driving the 16x2 displays, it is built in the board at the back of the display and takes a industry standard instructions set program. Other manufacturers followed the Hitachi...
  15. Externet

    Light Activated "Off" Switch, Or dark activated "On" switch

    What is the current these switches will conduct to ground when dark ? What is the voltage needed to be as not-ground when the laser hits the target ? A solar cell with a green-pass filter lens could be the base of the simple circuit.
  16. Externet

    Who built the Sun Tracker?

    There is two sun tracking devices that I know of; for solar irradiation perpendicular collection and for heliostats. I have built the second only, using an 'atomic' radiocontrolled clock modified to reverse the stepper driver direction when display shows 6:00 by the use of AND gates. No limit...
  17. Externet

    What Is Your Favourite Operating System & Why ?

    I use Linux since 2006. Ubuntu 10.10 now Sick of Windows, suffered about a year to get used to this geek-oriented operative system; and now I will not use other. It works all the time with no hickups and does everything I need and much more than that with no viruses, at $0, and...
  18. Externet

    Voltage level shifter

    Add a 0.7 V cell to the bottom of the series. Call it Vbatt0 Vbat0=0.7 Vbat1=4.3 Vbat2=7.9 . . .
  19. Externet

    Fan Caught on Fire in PC, Why Didn't the Fuse Blow?

    "Electronic components blow themselves up and smoke in order to protect the fuse" The more expensive the equipment is, the more consistently that rule applies. :rolleyes:
  20. Externet

    Wanted: CD22204 or MC145436 ICs

    If someone has these to sell/trade, please let me know; and what you may want. Am in USA. Thanks.
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