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  1. audioguru2

    touch switch

    12412, There is no schematic. There is a photograph, a sketch showing the completed circuit board and external wiring, a PCB pattern and a parts-mounting diagram. If there was a schematic then I could see how it works and how it does it. I could also see whether the parts are matched to each...
  2. audioguru2

    detection noise

    Badai, Tune the radio to a quiet spot between radio stations near the low end on the dial. When you move the radio near a motor, TV or monitor that is turned-on then the radio will make noise.
  3. audioguru2

    How do I make a dc circuit auto-off after 60 minutes

    Uman, The 555 is designed to be powerful, with a 200mA output. But it uses quite a lot of power-supply current even when not driving anything, which causes a small battery to run down quickly. There is a CMOS version called the L555 or ICM7555 which uses hardly any supply-current. It has a...
  4. audioguru2

    Novice has question about microphone.

    Alex, Be wary of 900MHz since it might pickup interference from all your neighbours' cordless phones, unless they've gone to 2.4GHZ and beyond. I don't like lavalier mics because they make it sound like the user (or TV announcer/reporter) is talking through a heavy blanket (or actually a...
  5. audioguru2

    "Cannot Connect", again and again

    I got another Fatal Error about 1 minute ago. That makes them nearly 1 hour apart, during which time I did a lot of navigation.
  6. audioguru2

    "Cannot Connect", again and again

    Mixos, I got the same Fatal Error message about 1 minute ago. It seems to be much less frequent. I also got one "connection with server cannot be established" message about 1 hour ago. One error per hour isn't bad.
  7. audioguru2

    sensitive low frequency filter

    Electrodoc, What happened to the previous low-bass circuit? Now you want 100-250Hz high-bass? You're making a colour-organ! I can see midrange coming next, then........ It would be complicated to add low-pass and high-pass filters to that kit circuit, and calculating its existing response is...
  8. audioguru2

    Novice has question about microphone.

    Alex, 1) Thanks for the great link about modifying radios. I like to modify and improve electronic items too. In your voice application, the music modifications won't apply. They talked about changing the de-emphasis capacitors: European radio stations use a different de-emphasis than North...
  9. audioguru2

    Analog/Digital GND

    MP, A motor is not analog, keep it away from audio and video, or you'll have lots of "alternator whine". Noisy things should have their own ground buss. (Like a school bus?) Many analog/digital products have separate voltage supply busses in addition to the separate ground ones.
  10. audioguru2

    Novice has question about microphone.

    Alex, Due to quite long audio wavelengths, the longer a shotgun mic is, the better it is. I don't think that a 2 1/2 inch mic is any good. The Audio-Technica shotgun mics are 6 to 14 inches long. Good-luck with its mounting to your camera.
  11. audioguru2

    Digital volume remeber settings? please help

    Stuee, You cannot simply apply power and audio to the device as the project's author implies. If you do, then the audio will cause the voltage of the resistor element to swing up and down, exceeding the absolute maximum negative voltage rating of the element (-0.5V), which will cause severe...
  12. audioguru2

    My 120 Watts Power Inverter

    Kasamiko, I'm glad to hear that your circuit works well. It should be good for 180W with a 24V CT, 7.5A transformer and if all the transistors don't get hot. How did you heatsink them? One heatsink for all drivers and outputs? What size? That is good for you to use a "snubber" circuit across the...
  13. audioguru2

    How do I make a dc circuit auto-off after 60 minutes

    Divide by 14??? OOOOOPS Sorry, I meant to take the output from the 14th stage, pin3. BTW, the number 2240 belonged to the XR2240, an obsolete chip that combined a 555 with a counter. EXAR are making much more sophisticated chips nowadays.
  14. audioguru2

    Novice has question about microphone.

    Alex, I did a quick search on Google and found a link that sells the quality ATR55 shotgun mic for only US$46. The link is here: http://www.atr55.com/ That is only the first link on Google. Also try a Froogle search. A local dealer probably won't come close. It certainly will pickup in the...
  15. audioguru2

    How do I make a dc circuit auto-off after 60 minutes

    Uman, I posted a link to the data-sheet, then later I posted a link to a whole 4060 timer circuit. If your computer can't open a PDF file, then download an Acrobat Reader from many manufacturers' sites. As I said earlier, the 4060 can be reset with a simple OR gate, made with diodes. One diode...
  16. audioguru2

    Multiplexing a 7107

    Manny, It sounds like your idea will work. What a nice challenge.
  17. audioguru2

    Digital volume remeber settings? please help

    Stuee, The DS1669 digital pot has memory built-in, so you can turn off its power and it will come back-on the same, but it updates its memory only if a change of 8 steps or more is made. The project that you referred has an error: the supply voltage is +,- 4V maximum, not +,- 5V. Your inputs may...
  18. audioguru2

    Novice has question about microphone.

    Alex, For long-range pickup that reduces background noise, consider a "shotgun" microphone. It is longer than a conventional mic and must be aimed at your subject, but may solve your problem very well. A not too expensive but high quality brand is Audio-Technica. They specialize in mics and...
  19. audioguru2

    Novice has question about microphone.

    Most of my comments about cheap transmitters apply to all of the FM transmitters in our Projects Section. I will say no more.
  20. audioguru2

    Novice has question about microphone.

    Alex, If the receiver doesn't have a mic-level output, then it will need an attenuator, unless your camera has a line-level input. The Sony receiver is probably digital, so it will probably be very fussy about receiving a signal that must be EXACTLY on-frequency, like a radio station. That, and...
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