My Interactive LED Table

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LED table

A few months ago I saw this Interactive LED Table on a bunch of blogs and instantly knew I must have my own. I contacted the people over at Evil Mad Scientist about their kits, and put in my order. That was in October, and I have been slowly building my table since then.

Monday, the electronic parts to my table came in the mail, I was thrilled, and since then, I have been assembling it. It looks pretty as you can tell from the above image. You can skip the whole walk through process and view the final table here. Or after the click you can get the whole step by step process it took to build it:

Step 1: Design of the Table

The first thing I did even before I placed my order was see if I could design a good looking table. I made a rough sketch on paper of what I was thinking, and mike took it to Sketchup

Sketchup model Sketchup model different angle

It consists of two 1×4 pieces of wood together in a 45° angle and another two inverted at a 50° angle. They hold up a tray of 1×3 46 inches long, by 31 inches wide which holds the LEDs.

After I decided I could make a good design, I put in my order for the 6 Panel kit with Black PCBs and the standard blue/white mix of LEDs for $400 not including shipping.

Next up was building it:

Step 2: Building the Table

Step 2 A: Building the Legs

At first I wanted to make the whole table out of MDF and paint it black. While at Home Depot looking at MDF, we passed the pine section, and I said, “wait, pine is nicer, and in the end, will be $5 cheaper too, lets use that.” So we got some 1×4 pieces of pine and brought them back to start working on them:

Because the 1×4 we got wasn’t exactly 1 inch by 4 inches, but rather 3.5 inches, we had some major issues getting the angles to match up, and ended up realizing it too late. So we had to make another few cuts, but we got it in the end. After We counter sunk the screws to hold the two pieces of pine together it was time to fill in all the screw holes and cracks with wood filler:

After allot of sanding and a few more coats of wood filler in the cracks, it was finally ready to get some stain on it.

sanded legs

I choose Minwax Cherry 235 as the shade of choice for my table. I gave everything 3 coats of stain (I like it dark, but didn’t want to go to a deeper shade of stain). Then 2 coats of Minwax Polyurethane

legs with poly on

Step 2 B: Building the Tray

The tray was harder then we anticipated. Ideally, I would have liked to have the ends of the tray a tongue and groove joint being held together by just wood filler. Unfortunately, not having a true dovetail jig, or a bit large enough was a problem. So instead, I just opted to screw the sides together, and fill them with wood filler. No big deal, and it’s not hard later on to make a new tray if I wanted.

For the bottom of the tray we used 1/8th inch thick MDF. We cut a groove 1/2 inch from the bottom of the 1×3 pieces 1/8th inch wide. The MDF was a major pain in the ass to get in there. And once we got it in, we determined we were never gonna take it out cause it wouldn’t have gone in nicely again. So I glued it in place, and filled the screw holes, and corners with wood filler:

underside of tray cornor of tray

After some more sanding, and another coat, it was time to stain and polyurethane it. The tray took four coats of stain because it was very light compared to the legs.

tray getting ready to stain getting ready to stain the tray

cornor of tray stained tray stained

finished tray

As you can see, I put down some paper to try and keep the stain from the sides off of the MDF bottom. That failed miserably. So on the last coat of stain, i ran the brush around the edge, under the paper to get an even color around the edge.

None of that would have been necessary had we done measurements on paper, and not in our heads. It turned out the tray was 2 inches too wide to hold the PCBs, so they had to be centered, and therefore, you would see edges. Oh well.

Step 2 C: Cross Braces

Because we wouldn’t know exactly how wide the tray would be until we built it, we couldn’t make the cross braces until then. So i put the legs on the floor, and rested the tray on top of them, took a piece of wood, and measured it, then did it again, and bam, two cross braces.

measure for cross brace measure for cross brace

Sand the edges off alittle, stain and polyurethane it, and that’s done.

Step 3: Putting together the LED part

Step 3 A: Putting the Resistors In

This was the most anticipating part of the whole process. Waiting for the circuit boards and LEDs, and everything else to come in from Evil Mad Scientist felt like forever, (however, it did allow me to work alittle to pay it off, so that’s ok too).

LED parts parts express stuff

The package came the morning of Monday November 26, 2007. I got it at lunch, and could barely pay attention in classes the rest of the day. At 4:30 when I was done, I began my (long task) of soldering…

First we put the microchips into their respective spots on all 6 boards, and stacked them on top of each other, they looked really good like that:

stacked PCBs

Next I took the first board, soldered on the power connector, and the switch, then soldered in all 4 microchips. While I was at class, Mike got bored, and inserted the various resistors into the board, all 59 of them. He left it for me to solder on.

cutting leads off of resistors bottom of first board

It was at this time that I noticed that one of the microchips was in backwards. Lovely. That set us back about an hour desoldering it, and we ended up just clipping it off, and using one of the extra chips they provided us and out it on.

Step 3 B: Matching, and putting in the LEDs

testing LEDs

Matching the LEDs was a major pain in the ass. 270 whites, and 270 blues to go through to get 40 whites and 40 blues that went well together in groups of 5 is the exact opposite of quick and fun. However, it was probably the most important process of building it.

matched LEDs mismatched LEDs

As you can see, the LEDs in the image on the left are dimmer, but all on. This is how they are supposed to look. One of the LEDs in the right image is burned out, and that’s why the other LEDs are brighter. Matching the LEDs was a process that took about an hour to 90 mins per board. It was painful.

80 LEDs matched

Now it’s time to put the LEDs into the board:

empty board top

And turn it on to test:

top of first board lighted up bottom of first board lit up

Step 3 B i : Repeat above x5

One board down, it took an estimated 4.5 hours to complete it. Now only 5 more to go. Looks like I’m in for a very long night/week ahead of me.

adding resistors soldering the resistors on board 2

board 2 finished adding the second board

movement accross the boards the boards with the lights off

The second panel went much quicker then the first one, partly because Mike and I put the resistors into all the rest of the circuit boars, and solidered them in at once. Then I matched another 80 LEDs and inserted them. Mike soliderd those in while I matched another 80 LEDs. We had a nice process going for those two panels:

LEDs leads LED leads

connecting the pannels inserting jumpers

3 pannels on in the dark movement accross 3 pannels

With 3 panels you start to get the effect of just how awesome it is.
I guess I forgot to take a picture of 4 panels, oh well, you can imagine what it would look like I’m sure.

5 pannels

Here’s a tease video of the 5 panel test:

6 pannels 6 pannels dark

all the leads clipped off all the leads clipped off 2

Look at all the leads clipped off of all the LEDs and resistors. By my calculations, it’s 2,316 individual points to solider. Yup, that was alot.

Step 4: Attach the Legs to the Tray

Originally, I had planned to use 3 inch bolts to attach the legs to the tray, with the tray in between the two legs. However, after getting the opinion of a few of my friends, it was determined that it would look better with the tray resting on top of the legs. This was easier said then done. We originally were going to rest the tray on top of the legs and be done with it, but, we forgot about the weight of the glass, all 85 lbs of it.

The idea changed into cutting the legs and making a slit in the MDF tray and inserting them inside. This is where the extra 2 inches on the inside of the tray served us well, because otherwise we would have had to do it the original, not as nice looking way.

cut legs cut legs

Next we had to cut notches out of the MDF in the tray to slide the newly modified legs through. This is where all that extra glue I used came back to haunt us:

cutting slits in the MDF cutting slits in the MDF

finishing up the slits Tray with slits in it

Now it’s time to bolt the legs to the tray:

screwing leg holes screwing holes 1

table on the floor table on the floor

That looks good doesn’t it?

Step 5: Putting the PCBs into the Tray

Oh we are so close to finishing it we can taste it.

mike putting boards in

At this point our lack of thinking ahead comes back to hand us again, and we’re stuck spending far longer then we should have screwing the boards into the tray. But we got it done:

standoffs on boards screwing in the boards

We used 1.5 inch screws to go through the bottom of the tray and hold up the boards. We figured out that it was better to have the LEDs closer to the glass so that they were brighter, it also was able to keep the boards off the bolts (which were now 3/4’s of an inch too long), but we put some electrical tape around them anyway.

Around the edge of the tray we put 1/2 inch wide speaker gasket to keep the glass from sliding around. I think it gives the table a beautiful, finished look as well.

speaker gasket full table with speaker gasket

Step 6: Put The Glass On

Last step, put the glass onto the table. I got the glass from Glass Tops Direct, which conveniently for me, is located in Long Island, NY, not very close, but close enough to save almost $100. I got the 36×48 inch 1/2 inch thick rectangle.

the final table

That’s it, the whole construction. Here’s a tally of the cost:

Item Price
6 Panel LED Kit from Evil Mad Scientist $420
36×48 inch half inch thick glass $140
Soldering Iron, Solder, extra tips,
black glue sticks, and speaker gasket from
Parts Express
$35
Wood:
8′ 1×3(1), 6′ 1×3(1)
8′ 1×4(2) 6′ 1×2(1)
4’x8′ 1/8inch thick MDF
$30
Stain and polyurethane,
big pack of foam brushes
$12
Nuts & Bolts:
1/2 x 3 inch (6)
Washers (6)
Nuts (6)
3/4 inch 6-32 screws & nuts
$12
Total: $649.00

Considering they go for over $2,000 already made I would say it was totally worth it to make it myself. It was a learning experience.

Now, without any further interruptions, here are the final photos of what it looks like (with and without glass) and a video or two of it in action.

final table no glass final table, no glass

LEDs on the table view of the table

floor view of the table

side view of table with glass corner view of glass

side view of table at glass level corner view of table at glass

table in the dark long view in the dark

paper towels paper towels in the dark

paper towels in the dark 2 paper towels in the dark 3

And here’s a video of what it does in the dark:

Many thanks to Windell at Evil Mad Scientist for his quick communication, and for just coming up with this awesome table idea.

33 responses to “My Interactive LED Table

  1. Pingback: MAKE: Blog
  2. Hey people, great job and the result is spectacular. I have the only question: why some LEDs on your boards seem to be replaced by resistors? Did you simplify something or what?

  3. Windell has a bit of broken code on his order page, and sends NASTY, MEAN replies when asked about ordering this so-called open source LED table.

    I tried to spend hundreds of dollars to get this table but Windell has a very bad attitude towards anyone who asks if this is really open source.

    He has not fixed the ordering page, he refuses to understand that I want to buy this product, and seems to think that he can get away with calling this open source (see the headline at the top of this page on his site- http://evilmadscience.com/majors/46-tables )

    Windell, if you’re reading this, I no longer want to give you my money. You really should read your emails before sending out your automatic nasty-grams!

    Never again will I attempt to give you hundreds of dollars OR help you fix your broken site. You deserve whatever loss of business you get from this.

    Signed,
    Three-time AttemptedBuyer

  4. Really!? They treated you that badly?
    Our corporate office main lobby can get by with some other kind of artistic gadget. The main wall can be covered in plasma screens for less cost.

    V.I.P

    1. I don’t have the schematic for the boards, you would have to ask Evil Mad Scientist for that, but they have newer boards that are less expensive, and you can buy one at a time now.

  5. I don’t know about the schematic for these tables, but there is one available for one a LOT like it at: http://www.instructables.com/id/Infrared-Proximity-Sensing-Coffee-Table-Module/ Basically the same setup but without the fading and blinking. I’m sure most of that can be added in if you tweak the code (available there) and schematics (also available there).

    It’s always nice how a EMS puts themselves out as “open source this” and “open source that”… but they still have yet to bother release’ng the schematics and the source. Last excuse I heard was they were tweaking the code or something like that, and didn’t want to release it till they had it just right. Either that have it right now, and refuse to release it. Or they’re just selling stuff with broken code… either way, no bueno.

  6. Hi
    thanks for your step by step page , but i really need the circuit diagram of ” Interactive LED Coffee Table”
    I searched all google but didn’t find the original schematic , can you help me?

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