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Posts posted by Um...Me123

  1. Being new to electonics I need some advice on building a very simple remote extender.
    I don't know very much about IR (well I'm certainly starting to in other research) or in using transistors and signal recievers.

    My seperate question:
    When you are using a reciever such as an IR one..it has to leads and looks just like a transmitterr/LED.

  2. I'm designing something.  Not sure what.  :o ??? Sort of.  OK nevermind that.
    I'm still new to electronics and somehow have trouble with 555.  I think I need to spend a day to just figure them out.  Anyway, I need an astable circuit that wil cause LED(s) to blink that can be adjustedd by a pot.  This would be like christmas lights that have the knob on the box.  I want them to go from steady on and down through fast strobe to either a very slow blink or completely off.  I will need an output of about 3V.  I just don't know what sized resistors and pot to use.  The bigger (higher resistance) the pot the slower it will blink?  Is there an easier way than using a 555?

  3. Sorry I haven't replied lately.  Because they have to work at night the camera might not work because the infra-red won't cover enough distance. (I need several hundred feet of coverage.)  Plus that would be expensive and the Nebraska weather will wear away at camera even if it's weather proof.  Also it would be prone to theif.  We don't ever have eye contact witht he area where it would need to be.  (There arent any buildings for it to be attached to wither)  I'm at school right now so I'll take some pictures and make a diagram or something to explain the situation better when I get home)
    Thanks guys.

  4. Hmmm well it's not done.  Have been really busy with school and I'm just taking a break from the project.  At first I was thinking "where did all my messages go?"  I continued with this project in the board meant for the LM317 supply and I can't remember if you had made any replies in there or not but if you go look you will learn that I hooked up the LM317 backwards and fried it and the pot.  I then re-wired it the write way and thats when I figured out the LM317 was bad so now I have de-solder it all again and guy new stuff and it's just a big mess.  So I took a little break until next time we happen to go by radioshack.b

  5. Thanks for your reply.  Starting to think no one would.  Rubber contacts? hmmm  This is the picture of the back of the area where the lcd and buttons are.  The green board seems to be just circuitry and the tanish one is the buttons along with some components (small transformer and some other).  Nothing seemed to be really dirty--this hapened not even a year aftet we got it so I dont know if being dirty is the problem.
    An urgent rely would be nice considering I have now put our good microwave out of service.  Where would we be without them?


  6. When I meant efficient I kind of meant the oposite but thats fine you answered my question anyway.
    So if the LED can damage skin that's why they arent used in effect lighting then and neon and incandecent are because they are lower frequencies.  What are uv LEDs used for then?  So you can make you own home CSI light?  (I guess that explains why regular black like tubes don't work very well like you see on tv...lower frequency.)

  7. If you have a video camera that has "Night Shot" or similar, will Infared LEDs work like invisible flashlights for the camera?  Can you just use a 555 to drive them 50% or do you use somthing else?  I don't know anything about oscillators (sp?) and just a little about 555s.

  8. Our microwave has a green LCD and it is very very dim.  Sometimes you can make out the the numbers if you squint at it really hard.  It started toing this a long time ago so I dont remember how long after we got it (few months maybe?)  Very rarely I have seen it work normally but that has only happend once or twice (over the period of a year or two) and for a short period of time.  Anyone know whats causing this?  Is it just a lose wire or something?

  9. Is a laser diode work similar to a LED?  It will just send out a straight laser beam right?  Is there any way to make a laser beam show up in the air (a physical line--not just a dot on a surface) without using fog or some spray (like CSI)?
    Ii am asking this because I noticed laser diodes on ebay that were fairly cheap and they will little gold colored canisters (smaller than a quarter) and had 2 straight pin leads.  They do the same thing as a handheld laser pointer?
    P.S. They have laser beam recievers dont they?  Just like infared recievers?

  10. Never even when you were really young (or whenever you started working with electronics)! :P
    Anyway, through a tangle of wires I hooked up what I believe to be a test using a 220 resistor instead of a pot and got .59V not center tapped.  The calculator said I should get 2.5 (on a 28V supply I think) so I'm guessing your right, the LM317 is history also.  Sigh......Thanks guys.

  11. Heres how I think I had the LM317 connected  so maybe you can help me figure out if it ruined.  I had the Vin wire conected to the ADJ--the ADJ wire connected to the Vout--and the Vout wire connected to the Vin.  Do you know if this would ruin it and is there a way to test it?  I did try it not center tapped once (25-28V) and thats when the pot fried so maybe that would fry the LM317 if the center tap didn't?
    P.S. This happens to everyone doesn't it?  They fry their first project.

  12. I think I have things hooked up the right way now but as usual there are still problems.
    First hooked it up and got a steady 19V out, the pot doing nothing.
    Measured the ohms on the pot and it seemed pretty messed up.  I think I was getting somewhere between 1k and 5k most of the time.
    I measured it the other way and got between 1 and 7k ohm so that seemed to be ok (is 7K normal?...on a 5K pot?).  This is center tapped by the way.  My output would go up just a few decimals higher than 7V and down to .1V.  Shouldn't I be getting more though?  Trans is 25V, half is 12.5V and doesnt the bridge give me an extra 3V (some poeple say it gives 3V some say it takes away 3V ???)  Seemed ok as I adjusted it except that I could not get 6V at all.  It would jump from 5V(point something) right to 7V.
    I'm thinking that the pot is broken because of the burning smell and buzzing noise it made a while back.  :P

  13. Weird things...
    Yes I believe it did go below 1V, I think it went to .7V.
    I tried it again not center tapped.  I got an output of 39V (how' s that happening?) no matter where the pot was.  Get this,  when the pot was at the one extreme it would make a slight buzzing noise and make a bad smell.  :D
    Sothing is totally wrong!  Anyway when I un-plugged it, the voltage dropped very slowly and my main switch is before the transformer (same as un-plugging) so if I want to be able to cut the power off instantly do I need to use a SPDT to bypass the binding post and drain the caps?

    Now that I think about it maybe it was 29V (sounds alot more logical) but I don't fell like plugging it back it when it seems to be burning.
    Should I just get a new pot from radio shack?  I thought pot seemed to be working when I tested ohms on it but I'll check again.

  14. I have built this supply and was testing it before finishing up some wiring then assembling it in the box.
    I was using a 25V @ 2A transformer and had it center tapped for the test.  As I adjusted the pot it would jump directly from around 10V down to 1V or lower.  What's causing this?

  15. This is a complicated issue and I'm a beginner at electronics.  I can't explain everything now but I need a way to "see" a car where it can't be visually seen.  There is a limitted area I can put sensors, recievers etc. but I will try to make a diagram eventually.  For right now i just need to know my options for sencing a car in daylightand night (I know, just night would be easy)  This has to have a long range of how far away it can "see" the car and then needs something such as a led to notify of an oncomming car.  It's very hard to explain but I can explain later once I find out my options.
    How do those things that you stick at the end of you driveway work?
    An infared beam (straight accross the street) won't work because I cannot put anthing at the place where I need to sence the car soon enough.
    Sorry if this is way to confusing!

  16. That switch is controling a seperate mains circuit from the transformer one (in the same box though)

    I was thinking...I am getting a 12' power cord that is the basic cord you would see on normal stuff (like the one on your soldering iron-2 conductor that is) to power this whole box.

    I get it now.  The DPST (or at least the type I was talking about) is designed for turning mains (thats what you call the 120V AC from the wall?) on and off and thats why that neon is bridged between!

    Ok so about those relays...you say to put a R-B diode accross the coil so you mean between the two terminals for the lower voltage input (I know...very poor terminalogy but I'm learning to explain better).  So if I want the electricity to only go one direction I need a diode right (like those 4 things in the bridge rec. right?)  What kind is this because there are all sorts of different kinds.  Can someone tell me how to put a picture in?  What do you put in the "img" tag?  The file name?  This way I can show you what my idea is that I think will work.

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