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  1. Old Steve

    how can I create a positive logic pulse from a steady high input?

    Of course you're right AK. I'm too distracted to think clearly on this right now, doing too many things at once, so I'll leave it to you.
  2. Old Steve

    Salvaged PIC, Usable???

    Yep, but you'll need a programmer w/ software to erase/reprogram it, and of course, a compiler to write the new program. They're a very useful chip, and erasable/reprogrammable many, many times.
  3. Old Steve

    how can I create a positive logic pulse from a steady high input?

    That diode should do it. Best you calm your Mum down now.....
  4. Old Steve

    how can I create a positive logic pulse from a steady high input?

    What about a series diode, with it's cathode toward R4? Again, not fully thought out. And still using a pullup R on pin 13.
  5. Old Steve

    how can I create a positive logic pulse from a steady high input?

    You don't have to worry about reliability of pulsing buzzers. They're as reliable as anything else. After all, the buzzer already has internal drive circuitry, otherwise it would need a drive frequency to make any sound at all, rather than simply applying DC. Fair enough if size is an issue...
  6. Old Steve

    Arduino vs raw PIC, Atmel etc

    So, I thought I'd ask a question, for a change. Everywhere I look, I see Arduino, Arduino, Arduino. What are the advantages of Arduino vs simply using a PIC or similar chip, with the appropriate extra components? Easier to code for? Cheaper? Definitely not smaller. And are they really viable...
  7. Old Steve

    Modifying pre made delay timer module

    Overkill. Sounds like a job for a 555.
  8. Old Steve

    how can I create a positive logic pulse from a steady high input?

    Wow, this thread's been busy. For some reason I've stopped getting alerts and email notifications for some of the threads I'm involved in, including this one. This circuit is more what I was thinking of. Looks good. Skidood, how come you don't want to use a self-pulsing buzzer/beeper? It would...
  9. Old Steve

    Not getting correct voltage from voltage regulator

    Right, I get your meaning now.
  10. Old Steve

    Light Ignition Circuit?????

    I know little about HPS or MH lamps. I'm not in that business, if you get my meaning. I was only describing how the chip works as I understood it from the datasheet. In fact, looking back, all I did was quote the datasheet.
  11. Old Steve

    External ringer for VOIP phone

    For some reason I didn't get an email notification of your replies. I was talking about buying the vendor solution to do this, and modifying it. Now that I've seen the cost, that's definitely out. Overall, you won't be able to do much better than Dave's solutions. It would be very hard, if not...
  12. Old Steve

    Mind & Infra Red Controlled Robot Car

    I've never even touched an Arduino, but from what i've seen they're a good beginner's tool, but not really suitable for serious stuff. They're more of a development board. The advantage of raw PIC, Atmel etc is that they are just a chip, and you add exactly what you need for your purpose. Not...
  13. Old Steve

    Not getting correct voltage from voltage regulator

    Steve, don't you mean 'appropriate'?
  14. Old Steve

    Not getting correct voltage from voltage regulator

    He already explained that he had the regulator connected using flying leads and had a bad connection. Going by the output voltage he was getting, it would have been a bad ground connection.
  15. Old Steve

    how can I create a positive logic pulse from a steady high input?

    I just grabbed a bit of paper and was going to roughly draw it up working from your schematic when it disappeared??? Can't do it now. Now no one will have any idea what I was talking about in my last two posts.
  16. Old Steve

    how can I create a positive logic pulse from a steady high input?

    Two gates of a 4093 can be used as a set-reset flip flop, then the two remaining gates could be used in series to provide the Schmitt trigger buffer for the positive pulse to the S-R 'set' input
  17. Old Steve

    how can I create a positive logic pulse from a steady high input?

    That would work. To cut the component count still further, you could remove the oscillator and the AND gate, drive an NPN transistor from the S-R flip-flop's Q output and have it switch a buzzer that beeps on and off automatically, something like this one:-...
  18. Old Steve

    Capacitor Questions

    I just found this, which might help:- http://www.allaboutcircuits.com/textbook/
  19. Old Steve

    Capacitor Questions

    Yep, 18VAC transformers are definitely available. You might have to hunt a bit to find one rated at about 3A. You'd want an 18VAC, 60VA, to use the correct wattage term. Here's a 1A version as proof of concept:- http://www.altronics.com.au/p/m2154l-powertran-12v-18v-240v-1a-ei-core-transformer/...
  20. Old Steve

    Capacitor Questions

    That looks healthier. Just increase that capacitor value to 3300uF or larger as suggested by Harald and you're in business.
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