Beer Pong Table with LEDs!!!! Help

Wendy

Joined Mar 24, 2008
23,415
OK, redid the layout where it is less awkward, reduced the number of green LEDs by 4, this is what I got...


BP0
..

BP1.........................................................................BP2

..

BP3........................................................................BP4

With the exception of file BP0, each one of these is part of the animation of LEDs. The LEDs lit on each image are grouped, they are all on at the same time. It would work pretty much the same for all the colors.
 

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adamcswant

Joined Mar 23, 2011
34
Thanks for the drawings. I think every 4th led lit would look good... but where do I put the resistors to control the current to the series of leds? what would the wiring diagram look like for something like that.
 

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adamcswant

Joined Mar 23, 2011
34
I have an arduino Uno board I just picked up... could that come in handy with making the lights do "things".

With the Green border I'm pulling 400mA @ 24v. If I light only every 4th led then I'm only pulling 100mA at a time. So can I use the arduino to control the 4 - 100mA 24v lines?
 

Wendy

Joined Mar 24, 2008
23,415
Thanks for the drawings. I think every 4th led lit would look good... but where do I put the resistors to control the current to the series of leds? what would the wiring diagram look like for something like that.
I just also realized that I'll be running 24v... will the 555 and the 4022 handle that?
No, but it really isn't a problem. They will be controlling several MOSFETs, which will turn the LEDs on/off, and the MOSFETs can handle that. The circuits are low power (extremely so), so a simple linear 12VDC regulator will handle their circuits just fine. You cluster the common set of LEDs similar to Figure 10.3 .

Thing I tried to do with the LEDs, 555s, Flashers, and Light Chasers article is one concept builds on another. In building this you are going to get a minor course in electronics.

What part of the world are you in? It helps to refer you for parts. Radio Shack has a MOSFET, but the fact is if you are willing to shop around you can get this stuff much, much cheaper elsewhere (and better quality in some cases). I refer to RS because they are nationwide to the USA and use part numbers, which prevents confusion. It is why the "old" hands have what part of the world they are in listed in their profile to be displayed on the upper right hand corner.

Do you want a separate light chaser circuit for each color? They are pretty simple, it might be better. If you want them synced that is easily done too.

Something to do is to think in terms of designations. The green LEDs can be DG1 through DG236, yellow LEDs can be DY1 through DY228, and red LEDs can be DR1 through DR224. I changed the quantity of red LEDs to allow it to be divisible by 4. I strongly advocate you draw to scale what you are wanting to do, you may find you want to change your numbers a bit.

Fine gauge wire can be used for simple point to point wiring under the table surface, which I assume is wood. The LEDs can be press fitted through holes in whatever material you wind up using. It never fails though, with this many LEDs one or two will be bad, so allow for the possibility and make it easy to change them out. The wires will be delicate, so have something to cover them up after you are done. It is up to you, but I wouldn't pot them in with epoxy, especially the wiring. This will make potential repair a nightmare later.

I'll glad to draw schematics, but decide what you want before I get started. I become a real grump when changes are introduced after the fact. :D
 
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Wendy

Joined Mar 24, 2008
23,415
I have an arduino Uno board I just picked up... could that come in handy with making the lights do "things".

With the Green border I'm pulling 400mA @ 24v. If I light only every 4th led then I'm only pulling 100mA at a time. So can I use the arduino to control the 4 - 100mA 24v lines?
Yes, if you know how to use it. I bought one a while back too, but I haven't even started with it yet (I expect it will take me around a year serious effort to learn). Programming, for me, is much harder work than designing hardware. If someone convinces you to use on be aware you're going to have to do the programing and hardware development. I'm sure you'll get some help, I don't know how much though (and it won't be me).

My inclination is simple jobs like the light chaser is mostly in the wiring of the LEDs. If you want a sensor circuit that lights where the cup was (or whatever) that is a job for a µC like Ardiuno.

Current has to be figured on a case by case basis. You have 3.2V as the Vf for the green LEDs. This is a reasonable figure, however, with semiconductors there is always variation. You may find the numbers are subtly off, either higher or lower than expected, and the errors accumulate. So lets say you use 6 green LEDs per chain, for a total of 40 chains (divisible by 4). Each chain pulls around 20 ma, and you have 10 chains at a time lit. This means 200ma for the green, maybe 10ma for the light chaser circuitry (probably a lot less).

A lot of design work is just making the numbers come out right in the end.

Like I said, before we get too deep into the electronics I would figure the table layout and where the LEDs go.
 
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Wendy

Joined Mar 24, 2008
23,415
One other thought, you do not have to use sequences of 4. It can be 3, 6, whatever you choose. Just make the LEDs multiples of the number of sequences.
 

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adamcswant

Joined Mar 23, 2011
34
So here's the general idea.... Unfortunately my supply for the leds changed and I'm trying to get verification on the forward voltage of the leds I will actually be receiving. According to their online specs all of them are 3.5 Vf...:confused: So I can't order resistors until that is finalized. I guess if it's true it will make things a little easier since I'm only dealing with one Vf instead of three.
 

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adamcswant

Joined Mar 23, 2011
34
If I just wanted the LEDs to be "On" all the time I would need a bunch of 150 ohm 1/4w resistors... would I need those same resistors if I did the chasing or comet trail?
 

Wendy

Joined Mar 24, 2008
23,415
Nope, you have to design for what you want. It may work out the same values, but may not. You have to go through the math and see.

Comet trails are just an enhancement of a chaser. You want em, you have to add more parts. No big deal, mostly.

The drawing basically works. The exact Vf can be figured by measuring 10 or so and averaging, it isn't hard to do.

***************

Allow me to restate what I said about comet trails, it will take several more chips per light chaser. It will require some original designing on my part. I like doing this kind of stuff, but you may not like the extra complexity. Let me know.

I think we're getting pretty close to me drawing something up.
 
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adamcswant

Joined Mar 23, 2011
34
Honestly I think comet trails would look the best. I would totally do the math... If I knew what to compute. Could we assume that the leds are all 3.5. If I see the drawing and know where the math lies I'd be able to adjust it if the voltages ended up different.
 

Wendy

Joined Mar 24, 2008
23,415
Generally you get within the ballpark with LEDs, and go from there. If it is within 10% of predicted value I would not worry about it. If a LED designed for 20ma gets 25ma it will have a slightly shorter lifespan, but these lifespans are measured in 10s of thousands of hours, so you have some leeway.

Let me think about this, and I'll start drawing. You are in charge of all the mechanical stuff (I am full or recommendations, or something) and I'll do the electronics design.
 

Wendy

Joined Mar 24, 2008
23,415
I haven't forgotten this thread, just putting some thought into how to do the comet trails. The actual sequencing is easy.

The attached drawing is a doodle. It doesn't work.
 

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adamcswant

Joined Mar 23, 2011
34
I'm glad you haven't forgotten about me. Thanks for all the help you've been so far. I've started to tinker with the arduino and it seems like small scale comet trails would be easy... but large scale is a whole different story.
 

Wendy

Joined Mar 24, 2008
23,415
That is what I'm finding. Basic switching for a color is two chips, both cheap, and 4 transistors. Adding a comet tail entails 4 transistors per channel (16 total). Not expensive, but more complex than I like. Part of the problem is the mismatch in power supplies. 4 transistors (per group) interfaces it. While typing this it has occurred to me how to get this down to 3 transistors per channel. I'll have a schematic up shortly.

On a slightly different subject I think you're going to need several of these for a interface between the table and the electronics.

http://www.radioshack.com/product/index.jsp?productId=2103229

http://www.radioshack.com/product/index.jsp?productId=2103983

http://www.radioshack.com/product/index.jsp?productId=2103982

http://www.radioshack.com/product/index.jsp?productId=2103228

I figure you'll need 13 connect points, 1 ground and 4 per color for the sequences. You don't have to use these, they just seemed ideal for the job to me.

As usual I'll state Radio Shack is not the cheapest source. They make great references though, and if you have trouble finding them anywhere else RS does have them.
 

Wendy

Joined Mar 24, 2008
23,415
OK, here is the first drawing. Some of the parts will have to be test selected for best performance.

If the delay is too long GR14 or GC1 will need to be decreased, if it is too short GC1 will need to be increased. Their is a good chance it will work well first time.



I don't like the number of parts for the driver, but it isn't as bad as I was thinking it was going to be.

This is one of four driver stages for the Green ring. Next step is to draw the actual sequencer, which will be much simpler.

Do you have any friends to help with this sucker that have a back ground in electronics? This is a perfect candidate for a a home brew printed circuit board.
 

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adamcswant

Joined Mar 23, 2011
34
How many Volts should the 47uf capacitor be? I'm going to take a wild guess, thanks to a quick google search, that QG11, QG12, QG13 are transistors...? What kind of transistor are they?
 

Wendy

Joined Mar 24, 2008
23,415
Low power switching types, 2N2222A (NPN, QG11, QG13), 2N2907A (PNP, QG12). It is what I usually use. The fancy numbers are because we are going to be repeating circuits over and over, and there is a code in the designation to say where the part goes. GR11 = Green Resistor <sequence 1><resistor 1>.

If you need help getting parts I have a deep stock. QG13 may need to be a power transistor. Odds are the 2N2222A will be OK, as it is within its voltage requirements. The part may get a little warm, but that is all I expect it to do. There are several reasons for that, most of the time it will be on (which will let it run fairly cool), and the time it will run hottest it will very brief.

You will need a 35V or 50V capacitor, 50V is better. Vcc on that schematic is 24VDC.

I may have to breadboard this myself to make sure it works.

One note about heat. I had a console when I was a maintenance tech that would die over the weekends, the normally temperature controlled test bed would over heat. The problem was the machine was left on over the weekends, and it generated heat under a table with deep edges. This trapped the hot air, and when no one was walking around the air sat stagnant and everything overheated. I mounted a simple fan under the table, they would turn it one for about a minute until the cooler got it under control, and turned it off again. With people walking around the table it stirred up the air where everything stayed cool.

You need to think about how this will stay cool. It doesn't need much air flow, but it needs some. If the air can't go anywhere it becomes an oven. You may not need a fan, but if it is in an inverted cup, hot air floats.
 
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Wendy

Joined Mar 24, 2008
23,415
OK, Sequencer done...



This is a fundimental decision point, any changes you want to make as far as the electronics now is the time. I drew 3 different sequencers, but you only need one. I think 3 would look better, but the first could drive all 3 LED rings at the same speed. It is up to you. The next 11 pages will be the LED page rehashed for the various clusters. I'm adding an extra page for the parts list in the front, so both finished drawings will be touched up a little.

I don't know if you use XP or not, but Windows Picture and Fax Viewer does a really nice job of printing these out. I will zip them up (14 files is a lot to load on an attachment) and put them up as an attachment on a later post.
 

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