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  1. audioguru2

    Who is using the oldest computer?

    Hi Guys, I'm back! A few days ago the IE4 on my old 486 computer got messed up (Kernel32.DLL errors) so I couldn't come to this site anymore (other sites worked fine). I was thinking that it's time to replace my computer, and I was drilling an ISP CDrom to make another 3V Chaser, then I realised...
  2. audioguru2

    Problems with headphones... static?

    Hi Acker, Maybe you have discovered the cause of your noise without realising it. Perhaps magnetic radiation from your computer is moving the coils in the headphones or inducing noise into their cable. The more distance between the radiation source (computer) and your headphones greatly...
  3. audioguru2

    Beginers OPAMP question

    Hi NGT, A good course about opamps is in our Articles section at the top of this page and is here: http://www.electronics-lab.com/articles/files/6_Op_Amps.zip Check the Articles index, it has all kinds of information about electronic devices.
  4. audioguru2

    op system

    A linx is a big wild cat, isn't it?
  5. audioguru2

    if invert a sound wave

    Hi Thunder, You can demonstrate the effect of an inverted sound wave easily by reversing the two wire connections to a speaker. It will sound exactly the same, but will no longer be in phase with other speakers that are connected. If you add a non-inverted sound wave with an inverted one, they...
  6. audioguru2

    3V LED Chaser project

    Hi Guys, I drilled a CD-R to make another chaser and Disaster! My workbench and I got covered in little bits of rainbow coloured metal, and the metallic film of the CD-R easily peeled off starting at the holes. A piece of tape removed the remainder of the metallic film. I didn't know that the...
  7. audioguru2

    AC current measurement

    Hi Soundboy, You described the function of a rectifier circuit. It can be a simple, half-wave rectifier using only one diode but will have a 0.7V loss and won't rectify signals below 0.7V peak. It could also be a full-wave "absolute value" rectifier circuit using a couple of opamps, without any...
  8. audioguru2

    Tlit switch

    Hi Gugh, I have never heard of a vibration switch, just a sensor as above. A sensor can be made to perform like a switch by amplifying its AC output then rectifying and filtering it.
  9. audioguru2

    Photodiode / LED Lightbar circuit - almost complete

    Hi Uman, You didn't post your circuit so I am just guessing at how it is connected: 1) Your photodiode is probably reversed-biased with a resistor to 5V. Therefore in the dark, its voltage output is 5V. 2) With light shining on the photodiode, it leaks current and its voltage reduces. 3)...
  10. audioguru2

    3V LED Chaser project

    Thanks Trigger, I am using 74HCxx ICs that are guaranteed to supply a strong output current with a supply of only 2V, which is what the 3V battery will be at the end of its life. Ordinary CD4017 ICs are guaranteed to supply hardly any output current with a supply of 3V, and probably don't work...
  11. audioguru2

    3V LED Chaser project

    Hi Dazza, You might have a big problem with availability. The various manufacturers all have different codes, but my ST-Micro datasheet lists the "M" suffix as a surface-mount package. Double-check with Farnell. Texas Instruments further confuses things because some of their 74HC ICs have a CD...
  12. audioguru2

    3V LED Chaser project

    Hi Ante, A big joke over here was, "What are we going to do with all those free ISP CD Roms?" I found a use for them. While searching in my son's room for his digital camera, I discovered that his stack of virgin CD-Rs or CD-RWs create a very intense rainbow reflection effect, so i "borrowed" a...
  13. audioguru2

    3V LED Chaser project

    Thanks Ante, I'm making a bunch of these 3V Chasers. I gave one to my (grown up) daughter for her birthday yesterday, and she says her friends will want them too. My friends and rest of my family also want them. In my pics is my new Taiwan copy of Veroboard. It seems to be made of compressed...
  14. audioguru2

    3V LED Chaser project

    Burp! 'Scuz me. Let's see. The Guinness is upside down. I will also be upside down. If I glug it really fast, it won't flow into the sky. Right, mate? G'day t' ya. ;D ;D
  15. audioguru2

    3V LED Chaser project

    Thanks Dazza, Sure you can make and sell these thingies, I didn't patent anything. I just design them for fun and the challenge of making them work well with a power supply as low as 2V. My only condition is that if I ever visit down under, you buy the 1st round of Guinness. ;D ;D :'( :-*...
  16. audioguru2

    Tlit switch

    Sure, you can add circuitry that will turn off the alarm after it has sounded once. But if you ignored the alarm by not straightening the bike to reset the tilt switch, the alarm is useless if you also disregard its tilt switch after the 1st alarm and turn the alarm off. Maybe you need a...
  17. audioguru2

    Tlit switch

    Hi Gugh, If the tilt switch is still making contact after the automatic reset has passed, then of course the 555 is triggered again. It will continue to happen until you straighten the bike! You could turn off the alarm if you don't want it to trigger when tilted. Maybe you want the alarm to...
  18. audioguru2

    3V LED Chaser project

    Hi Guys, (And warm greetings to the ladies amongst us) Here's a pic of two 3V LED Chaser projects. It was difficult to snap a pic at the moment when both are lighted (even though they were chasing at high speed). Between them might be the next project that I post, it very slowly dims and...
  19. audioguru2

    Little help please!

    Yes Ante, I agree that separate chargers are best. Murphy's Law says, Ka-boom, oops the switch was in the wrong position! 7807? I've read about them, never seen one. ;D ;D ;D My first happy face had too much to drink.
  20. audioguru2

    Little help please!

    Hi Stuee, If the radio has charging circuitry built-in, it will draw only what it needs, 70mA. But the current could triple or more if the radio is in operation while charging its battery. You don't need an expensive, complicated switching regulator for only 70mA. An inexpensive LM317T linear...
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