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Old 09-29-2012, 04:15 PM   #51
Magialisk
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J187,
I think what you're looking for is something like the diagram I posted back on page 4: http://www.homebrewtalk.com/f51/simp...ml#post4393542.

Granted that diagram was for a dual circuit design based on a 556 timer, but it shows every single wire and connection on the breadboard and I'd wager a non-engineer could split that diagram conceptually down the middle and wire up a 555. To be clear, on a 555 pins 1-8 are not the same as pins 1-8 on a 556, but that aside the rest of the circuit would be wired identically after accounting for the correct pin numbers. Here's the pin mapping that would have to be done for a 555 based diagram:
My 556 Pin Correct 555 Pin
1 7
2 6
3 5 (no connections anyways)
4 4
5 3
6 2
7 1
8 8

For what its worth, my opinion would be to stay away from perf boards and wire wrapping or soldering unless those activities are something you enjoy / are good at. It's just so easy to wire up a breadboard since all you have to do is cut and strip wires and press them into the holes. The signal distribution and power busses are done inside the board for you. If you wanted I could draw you up a breadboard diagram just like the one on page 4 but for a 555 circuit. It should only take a few minutes to modify the one already posted.

 
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Old 11-02-2012, 07:31 PM   #52
Kaiser
 
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I'm going to try this. My current stir plate has the issue that there is only a narrow band in which I can control the fan speed. And I'm using a LM317. Thanks for posting the part list and such. I have experience with building electronic stuff (used to be my hobby before I took a job in the computer industry) but finding suitable parts is always a challenge.

Kai

 
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Old 11-04-2012, 03:59 PM   #53
buck57
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Quote:
Originally Posted by buck57 View Post
Thanks rocketman. Even if the numbers have changed, at least i can figure out what the new item number will be. This will be fun!
Rocketman - successfully got the parts on the list from Mouser. As I am putting this together from your build diagram, I noticed that there is an unlabeled diode/resister? that bridges the motor leads. Is this an R1, 1 or 3, or a diode?

If I pursue the Mosfets option #1 that you recommend, do I need the R3 resister?

Thanks

 
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Old 11-04-2012, 09:06 PM   #54
nmfree
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Quote:
Originally Posted by buck57 View Post
As I am putting this together from your build diagram, I noticed that there is an unlabeled diode/resister? that bridges the motor leads. Is this an R1, 1 or 3, or a diode?
It's an unlabeled diode:
Quote:
Originally Posted by rocketman768 View Post
Diodes: 1N4933-E3/54
Quote:
Originally Posted by buck57 View Post
If I pursue the Mosfets option #1 that you recommend, do I need the R3 resister?
I don't believe so.
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Old 11-05-2012, 01:21 AM   #55
buck57
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Quote:
Originally Posted by nmfree
It's an unlabeled diode:

I don't believe so.
Thanks nmfree

 
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Old 11-08-2012, 07:47 PM   #56
buck57
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The diagram shows the mosfet leads as DGS but the datasheet typically seems to be GDS. should the wiring be made to adhere to the pins as shown on the datasheet? In other words does G always goes to position 3 on the 555 regardless of it's position on the mosfet? Thanks

 
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Old 11-10-2012, 01:38 AM   #57
nmfree
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Quote:
Originally Posted by buck57 View Post
In other words does G always goes to position 3 on the 555 regardless of it's position on the mosfet?
Yes. Manufacturers like to be special unique butterflies about package pin positioning sometimes.
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Old 11-17-2012, 03:48 AM   #58
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Works for me

I did have 2 challenges, though. I got a Arduino board like this one: http://www.mouser.com/Search/Product...key782-T030081 but didn't know that there are connections between the holes. So I ended up spending a while on troubleshooting why the design sucks so much power

Then I connected R1 to GND by mistake and had to think hard how this circuit works and found that C1 never charged.

But I can't get the motor speed down to really slow. I think this is because R1 is fixed and the min pulse with is thus fixed by the time it takes to charge C1 through R1. I saw many designs that charge C1 through one side of the potentiometer and discharge it through the other side. this way you can get the pulse with really short.

Have you tried this? I'm giving this a try.

EDIT: I did try this and it works well. I'll keep it that way. But it takes 1/4 turn to get the motor moving since the very short pulses are not strong enough.

Kai

 
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Old 11-17-2012, 04:28 AM   #59
Schlomo
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Your lingo makes me wonder why im studying computer engineering. I hate v dividers... Dont get me wrong, they work great and have many applications, i just hate studying and being tested on them.

 
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Old 12-01-2012, 12:21 AM   #60
Jackjama
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I built this on a bread board using the values on the front page. My fan goes from a medium speed to a fast speed. I need to get it to go slower. Either i have hooked something up wrong or i need some different values on some of my components.

I have double checked the drawing and i fell like everything is connected correctly. I used the values on the drawing. The only doubt i have is the capaciter. The capaciter has a long wire and short wire. I hooked the short wire to ground and the long wire to terminal 6. Is this correct? The data sheet said the long wire is positive.

I am guessing i need to go up on either r2 or c1. Any suggestions?

 
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