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tequilaWorm
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Registered: 10/21/07
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Timer Schematics
#7594516 - 11/04/07 12:55 PM (16 years, 2 months ago) |
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Alrighty, so to make the whole cultivation experience I tad bit more exciting, I've decided to wire up my own timer for my computer fan FAE with a LM555 chip.
Anywho, all I was wondering is if it was possible to judge the polarity of the output terminals on this schematic (if so, I'd assume the bottom would be positive). If not, however, is it because it doesn't matter?
[Just to be sure, the bottom-left lead is the negative input, correct? If not, then I'm really looking at this wrong.]
Should I run the negative lead of my power supply through the ground input (bottom-left lead), or leave it as a floating ground connected to nothing?
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Pictures of custom timer for automated FAE coming soon... and of course, some of the musshh.
Edited by tequilaWorm (11/04/07 02:19 PM)
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tequilaWorm
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The schematics may be handy! [It's the second one I'm wiring up. I'm modifying it to be 6600 seconds off - 600 seconds on (ten minutes of every 2 hours).]
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Pictures of custom timer for automated FAE coming soon... and of course, some of the musshh.
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windex
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Its been a while since I've read one of these but it looks as if the bottom is your common ground and pin 3 is your positive.
See how everything moves from the positive at the top left and eventually gets to the bottom line.
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tequilaWorm
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Re: Timer Schematics [Re: windex]
#7594628 - 11/04/07 01:33 PM (16 years, 2 months ago) |
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I see what you mean. Here's a schematic of the 555 chip itself.
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Pictures of custom timer for automated FAE coming soon... and of course, some of the musshh.
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tequilaWorm
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Re: Timer Schematics [Re: windex]
#7594641 - 11/04/07 01:35 PM (16 years, 2 months ago) |
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Quote:
windex said: Its been a while since I've read one of these but it looks as if the bottom is your common ground and pin 3 is your positive.
See how everything moves from the positive at the top left and eventually gets to the bottom line.
In reference to that 555 schem, it looks like you're right. Thanks.
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Pictures of custom timer for automated FAE coming soon... and of course, some of the musshh.
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tequilaWorm
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Registered: 10/21/07
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Should I run the negative lead of my power supply through the ground input (bottom-left lead), or leave it as a floating ground connected to nothing?
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Pictures of custom timer for automated FAE coming soon... and of course, some of the musshh.
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trendal
J♠



Registered: 04/17/01
Posts: 20,815
Loc: Ontario, Canada
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The negative lead is likely not a negative lead at all...it's most likely a 0v or ground lead. Black wire, right?
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Once, men turned their thinking over to machines in the hope that this would set them free. But that only permitted other men with machines to enslave them.
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windex
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Re: Timer Schematics [Re: trendal]
#7594888 - 11/04/07 02:58 PM (16 years, 2 months ago) |
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Its been to long to make any kind of firm decision for you.
I can tell you if i were building it based on what I see here I would try connecting that bottom rung to 0v or gnd before the neg terminal.
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windex
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Re: Timer Schematics [Re: trendal]
#7594921 - 11/04/07 03:05 PM (16 years, 2 months ago) |
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From what I've been reading the 555 chip would be aweful for anything over 5 minutes.
Edited by windex (11/04/07 03:06 PM)
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windex
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Re: Timer Schematics [Re: windex]
#7594950 - 11/04/07 03:12 PM (16 years, 2 months ago) |
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Hmm, nvm, turns out this site I was reading was trying to sell their own more expensive timed relays.
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tequilaWorm
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Re: Timer Schematics [Re: windex]
#7595089 - 11/04/07 03:56 PM (16 years, 2 months ago) |
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Quote:
windex said: Hmm, nvm, turns out this site I was reading was trying to sell their own more expensive timed relays.
Haha, typical. I just got back from picking up a big 2200 microF capacitor to ease up on the resistor-count, and the necessary diode. Timer should be fine, seeing as how the expected outcome needn't be exact. My power source is just a 2-pronged 120vac-to-9vdc transformer. Are the leads hot and ground, or positive and negative?
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Pictures of custom timer for automated FAE coming soon... and of course, some of the musshh.
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tequilaWorm
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Re: Timer Schematics [Re: trendal]
#7595096 - 11/04/07 03:58 PM (16 years, 2 months ago) |
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No color difference, only coded on the outside with the positive wire having a white stripe down it.
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Pictures of custom timer for automated FAE coming soon... and of course, some of the musshh.
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trendal
J♠



Registered: 04/17/01
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Loc: Ontario, Canada
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They are positive and ground. If you have a meter you can verify this by checking the leads against your house ground.
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Once, men turned their thinking over to machines in the hope that this would set them free. But that only permitted other men with machines to enslave them.
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tequilaWorm
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Registered: 10/21/07
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Re: Timer Schematics [Re: trendal]
#7595143 - 11/04/07 04:12 PM (16 years, 2 months ago) |
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I have a digital multimeter. How can I go about checking it against my house ground?
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Pictures of custom timer for automated FAE coming soon... and of course, some of the musshh.
Edited by tequilaWorm (11/04/07 04:21 PM)
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trendal
J♠



Registered: 04/17/01
Posts: 20,815
Loc: Ontario, Canada
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Turn it on a volts measurement...20v to 50v is fine, just make it higher than what you're testing (9v in this case).
Connect the black probe to your house ground (I just stick it in a plug - MAKE SURE you get it in ground though!. Then connect the red probe to one lead after the other on the wall-wart to see which one is positive and by how much. One of the leads should be at ground or as close to ground as possible (I've seen it a little above ground in some cases).
If you electrocute yourself doing this, it's not my fault
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Once, men turned their thinking over to machines in the hope that this would set them free. But that only permitted other men with machines to enslave them.
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tequilaWorm
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Registered: 10/21/07
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Re: Timer Schematics [Re: trendal]
#7596173 - 11/04/07 08:15 PM (16 years, 2 months ago) |
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Alright, I finished up wiring the circuit (put it all on a board and fastened it onto a small plastic backing). I've got it running right now; good news is that the fan is on and has been on for the last 3 minutes. I'll just keep it nearby and see if it'll go off in ~7, and turn back on in another ~110.
Wish me luck. I'll try and post some pictures of the finished product some time.
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Pictures of custom timer for automated FAE coming soon... and of course, some of the musshh.
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tequilaWorm
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Registered: 10/21/07
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Thanks for all your help guys.
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Pictures of custom timer for automated FAE coming soon... and of course, some of the musshh.
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