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dadxd Semi Newbie
Joined: 09 Aug 2009 Posts: 6
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Posted: Sun Aug 09, 2009 8:54 pm Post subject: Smallest possible LED stoplight circuit |
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I am trying to make a circuit small of enough to fix on something the size of a business card. I have soldering skills. I know basic circuit design I just don't have a wide knowledge of parts.
I want it to simply go in the stoplight pattern
GREEN ON
GEEN OFF YELLOW ON
YELLOW OF RED ON
REPEAT
I plan on using one of the small "watch" batteries. If possible I would like to pick up these parts at Radioshack.
I will also more than likely mount a SPST of/off switch.
Also if it isn't too many more parts a dial to adjust speed would be cool.
Thank you. |
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Alan Site Admin

Joined: 29 Jan 2006 Posts: 1399 Location: Winnipeg, MB
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Posted: Mon Aug 10, 2009 5:08 pm Post subject: |
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| Use a microcontroller such as a PIC 16F628 to run it. |
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dadxd Semi Newbie
Joined: 09 Aug 2009 Posts: 6
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Alan Site Admin

Joined: 29 Jan 2006 Posts: 1399 Location: Winnipeg, MB
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Posted: Tue Aug 11, 2009 12:06 pm Post subject: |
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| dadxd wrote: | http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en010209#2
Which one do I need to order?
And what would be needed to program it? |
They are different packages, for example if you don't mind a DIP package you could use this one. PIC16F628-04/P, there are also surface mount ones but they would be harder to work with.
There are many programmers available with many price ranges. Do a Google search for the chip and the word programmer to see a good variety. There are also many on Ebay. |
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dadxd Semi Newbie
Joined: 09 Aug 2009 Posts: 6
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Posted: Tue Aug 11, 2009 11:27 pm Post subject: |
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Ok I have a new idea. What if I used like a 555 timer right?
Then I have 3 LED's, between each LED is a fairly large capacitor. The capicter would take maybe like .5 second to fill and then light the LED. If I placed these in between they I could get the pause effect just not the on/ off effect which is ok.
Would this work? |
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Alan Site Admin

Joined: 29 Jan 2006 Posts: 1399 Location: Winnipeg, MB
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Posted: Tue Aug 11, 2009 11:58 pm Post subject: |
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| dadxd wrote: | Ok I have a new idea. What if I used like a 555 timer right?
Then I have 3 LED's, between each LED is a fairly large capacitor. The capicter would take maybe like .5 second to fill and then light the LED. If I placed these in between they I could get the pause effect just not the on/ off effect which is ok.
Would this work? |
Yes you could do this with a 555 timer but it would not be as flexible as using a microcontroller, you would also need more parts if you used a 555.
Do you just need one of these or lots? If you need one custom made please PM me and we could work something out. |
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dadxd Semi Newbie
Joined: 09 Aug 2009 Posts: 6
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Posted: Wed Aug 12, 2009 3:38 pm Post subject: |
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I really don't need it to be flexible. Just simple.
Could you give me an idea on parts I might need? |
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Alan Site Admin

Joined: 29 Jan 2006 Posts: 1399 Location: Winnipeg, MB
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Posted: Wed Aug 12, 2009 5:08 pm Post subject: |
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| dadxd wrote: | I really don't need it to be flexible. Just simple.
Could you give me an idea on parts I might need? |
I am not a 555 timer expert. I have used them is lots of circuits years ago but these days microcontrollers have made them redundant in most cases.
Have a look here for 555 timer details that should get you going.
http://www.williamson-labs.com/480_555.htm
The simplest way to set it up I think would be to set up 3 timers and have the first trigger the second and so on. |
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dadxd Semi Newbie
Joined: 09 Aug 2009 Posts: 6
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Posted: Wed Aug 12, 2009 6:45 pm Post subject: |
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| So 3 timers would be better than just 1 timer with several capacitors? |
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Alan Site Admin

Joined: 29 Jan 2006 Posts: 1399 Location: Winnipeg, MB
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Posted: Wed Aug 12, 2009 7:31 pm Post subject: |
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| dadxd wrote: | | So 3 timers would be better than just 1 timer with several capacitors? |
How would you be able to get three signals out of one timer? There might be a way that I can't see. If you can do it with just one that would be much better. Even as far as parts count goes you would be far ahead. |
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dadxd Semi Newbie
Joined: 09 Aug 2009 Posts: 6
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Posted: Wed Aug 12, 2009 8:28 pm Post subject: |
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Well I wouldn't be trying to get 3 signals.
It would be like
red on
pause
red on yellow on
pause
red on yellow on green on
pause
restart
I am just trying to figure out what would be the best ways bewteen a pause |
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Anothercoilgun Semi Newbie
Joined: 04 Jan 2009 Posts: 6 Location: CA, USA
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Posted: Sat Sep 19, 2009 7:44 pm Post subject: |
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| dadxd wrote: | Well I wouldn't be trying to get 3 signals.
It would be like
red on
pause
red on yellow on
pause
red on yellow on green on
pause
restart
I am just trying to figure out what would be the best ways bewteen a pause |
All you had to do is ask
Link to auction.
If using 3v battery the regulator can be bypassed. This is a picture of the auction item with no regulator and built in button switch. The LED's are 1206 size. I only had white color to demonstrate. As you see only 3 LEDs are used so 3 patterns are made for those 3 LEDs for what you need.
Video link below:
http://www.anothercoilgunsite.com/3lights.wmv
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Alan Site Admin

Joined: 29 Jan 2006 Posts: 1399 Location: Winnipeg, MB
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Posted: Sat Sep 19, 2009 7:58 pm Post subject: |
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| Nice tiny board! What controller is that using? |
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Anothercoilgun Semi Newbie
Joined: 04 Jan 2009 Posts: 6 Location: CA, USA
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Posted: Sat Sep 19, 2009 8:48 pm Post subject: |
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Its a 16F688 native 14 pin but 16 pin in QFN package. It has treated me very well the past year  |
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Anothercoilgun Semi Newbie
Joined: 04 Jan 2009 Posts: 6 Location: CA, USA
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Posted: Wed Oct 28, 2009 11:43 pm Post subject: |
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I lied.
I now have a smaller board for those hard to fit places.
This one measures 14.5 x 14.5 mm (0.570 x 0.570 in)
Notice those tiny block dots. Those are 0402 size resistors.
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