Introduction: The Much Larger Board of Many Ping-Pong Balls
First Prize in the
LED Contest with Elemental LED
Step 1: Things You Should Know
Firstly - I sell (or try to sell :-) ) kits. Unfortunately, I am a Brit (not actually unfortunate, just impractical). This means shipping abroad is expensive. Very expensive. This means that for this, I cannot sell the wood parts, or anything that is not the electronics. If you buy a kit you get all the network cables, PCBs, ICs, Components, and LEDs. If you want to get the boards fabricated yourself, never fear, they have been open sourced under CC-BY SA V3.0 Unported and Eng+Wales. As for the laser cut wood panels, the DXF files are released under the same license. All you have to do is send the files to your local friendly CNC turner or Miller, pay him, and get some nice identical panels (though without my blog etched onto them :-) ), and you can pick any wood you like, and save yourself about £150 in shipping (no joke, that is what it would cost).
Secondly - The stand and frame are the only things that were manufactured by hand. There are no CNC files for these. In this instructable I will go over how I made my stand and frame, then an alternative method without requiring a full on workshop, then a guide on how to design your own if neither of these are to your liking.
Thirdly - Ah the joys of copyright. Initially I found another project, a matrix of the same size, and used their computer-side code. I then modified it, as allowed, ported it to my hardware, and added animations for my specific purposes. The problem is, that due to their licenses, I cannot redistribute my modified code. I do have my own original code, but it is still in the pipeline, and not ready for others to use it, its a bit of a "poke it with a stick" type program. Never works first time, until you kick it. Aaaannnnyyway, I digress; there is a solution to the problem, in that instead of giving out the modified code, I modified my electronics design to work with the code, without modifications or porting. Unfortunately, the electronics are worse because of it, but until my code is ready, that's just the way things are. (The code is from solderlab.de)
Step 2: Thou Shalt Need...
Tools for the main stuff...
Glue Gun (preferably with glue :-) )
Drill with 5mm bit
Soldering Iron (with solder, a WET sponge, stand, and a de-soldering sucker if you think you will make errors)
Possible tools for the stand and frame...
Pop Rivet Gun
You can get them all here
Electrical Stuff... You can get a kit of all this stuff here
512 Common Cathode LEDs
74HC595 Shift Registers
Stand and Frame will be listed when we get to it.
Step 3: Glueing in the Balls
IF YOU WANT TO PAINT THE WOOD PANELS, NOW IS THE TIME TO DO IT!!!!!!!!
This is the fairly self explanatory bit, but there are a few nice build tips here, so it is quicker and looks even better. The picture of the board is the one generated from the CAD program for the last one, it's not identical, but you get the general idea. After you cut it / buy one from me, this is what will be staring you in the face.
The next step is, surprise surprise, glueing on the balls. When I built this one, I did the balls in lines of 4, by getting the board upside down, then putting the balls under it, wobbling the board around until they aligned with the holes, then glueing them. This was inefficient and ineffective. You then had to wait for ages as the hot glue dried, before you could lift it again to get the next ones under. When building my new, bigger one (not yet finished), I had a new method, which is much quicker. Here goes...
For this way you need to find any flat object the size of the board, be it a bit of Ikea flat-pack furniture that to this day you cannot find where it was meant to go (this was me), a bit of wood, or some strong cardboard, or whatever.
1. place the board RIGHT SIDE UP, so that you can see the side that you want to be the front (probably the side without burn marks, or if you want to stain it / cover it in stickers.etc, then that side.
2. Place all 64 ping pong balls (note, make sure that they are all white with no markings, unless you want them for style) on the board, in the holes. They should sit neatly on top. If you are going to stylise it, then this is how it will look when glued.
3. Place whatever flat thing you have selected on top of it so that it covers the whole board. Them, holding it firmly, flip it. The rear side of the board should be facing you, on top, with the flat thing on the bottom, with the balls sandwiched in between. Looking at the board from above you should see the balls through the holes. If you need to, adjust some so that they fit neatly.
4. Glue (with the hot glue gun) round the edges of the holes, touching the balls. The seal should go all the way round. It will secure the balls to the board, without the glue being visible from the front. On some balls, you might see bubbles rising through the glue, and possibly hear a strange deflation sound. This is because the hot glue has melted a bit of the ball, and as it is under pressure inside it, some of the gasses escape, causing the bubbling. This is not a problem, but take it as a hint to more on to glue the rest of the circumference, or if finished, the next ball.
Repeat this for all 8 of the panels.
Then it's time to drill the ping pong balls. You can use any sort of drill or dremel, but you need a 5mm bit.
I won't bother going into the details. If you can't use a drill then this project probably isn't for you, but here are a few tips:
-- Too much pressure can break the glue seal and the ball could fall out, this is not a good thing.
-- If you use cheap balls like me, you will get lots of plastic scrap round the edge of the hole. Depending on whether you want it inside the ball or outside, you can use either direction on your drill, the friction is enough to make the hole.
After you have done all the panels, it's not a bad idea to lay them all out so that you can see if there are any problems, and get an idea of how it will look. I have attached a picture of mine when I did that.
IF YOU DON'T KNOW HOW TO USE A HOT GLUE GUN - READ THIS
Ok, solid glue tubes go in, melted glue comes out, melted glue solidifies.
Just put the glue stick into the back of it, then plug it in (turn it on if it has a switch, many don't).
Wait a bit, then put the tip on the bit that need glueing. Pull the trigger, hot glue comes out.
You can slowly pull the trigger, and drag it, to glue a large area, OR ROUND THE EDGE OF A HOLE ON AN LED MATRIX
Step 4: SOLDER TIME !!!!!!!!!!!!!!!
Yes. By now you will have all the panels, ready for LEDs. You will have spent probably a day on this up to now, and are feeling sorry for yourself. Just wait till after the soldering. If you have never soldered before, it could take over 100 man hours. With experience that time will shorten.
In reality this is probably too much work for one person. I taught some people how to solder, and then they helped me do the soldering, splitting the work. Thank you nice people :-D
I used bare copper wire, as it is SSSOOOOOOOOOO much quicker than stripping sheathed wire, but if you can't find any....
Step 1 - Arrange the panels face down so that they all tile. You now know where they all go. Mark each panel with an UP direction. Some are obvious, but the three identical corner pieces can e confusing, and you need to know which way to do the wire grids
2 - Put all the 64 leds in the holes in the ping pong balls. Make sure that they are all orientated the same way, otherwise it will not work. Bend the longest of the 4 pins on the LED down towards the bottom of the board, so that they are at about 45 degrees. You are not doing these immediately, but they need to be pointed in the right direction. On one side of this pin there will be one pin, and on the other, 2. The pin on the side of the longest pin with only one pin is usually the red one, but that doesn't matter. Bend it to about 30 degrees from the wood to the side it is on. On the other side of the longest pin there should be 2 pins left. Bend the outermost of these out to the side it is facing, and slightly down towards the bottom of the panel. Leave the last pin facing upwards.
| | | | Here is a crude picture of the LED pins, so from the left
| | | | 1 goes to the left and slightly down to the bottom
| | | | 2 is left vertical
| | | | 3 is bent down towards the bottom
| | | | 4 goes to the right
Do this for all the 64 leds
3. SOLDER 'EM
Everybody has a different style, some people weave the copper wire under and over the pins in the line, some go over them all, but tighten the wire by bending it over the sides of the panel. Just go with whatever works for you.
LEAVE EXTRA WIRE, AND DON'T CUT IT OFF, YOU NEED THIS LATER ON
FIrst do the "Red" pin (the one with a side all to itself). This is a column, so the wire should go top to bottom, and get all the 8 pins in that line.
Next do the other extremity pin. This is also a column. After you have done both of these, tape over them with insulation tape. You should cover all the wires in the "led area" (ie ignore the extra wire), and the pins. Any of these can cause a short.
Thirdly, bend the vertical pin to the side it is on. It should be over tape. This is also a column. Tape over it as before.
The last pin (bent down towards the bottom) is a row, the wire should go from side to side, getting all 8 pins. This needs taping as well.
STEP 4 - Test it. Get a power supply and stroke the negative lead (black) over the wires that come out at a side, and the red positive lead over the wires that come out of the top or bottom. You should see light, this is as good as testing gets at this stage. Make sure that the power supply is low power (minimum forward voltage of the LEDs) as not to damage the LEDs. If you are worried, you can use resistors, but if you stroke quickly you will not need them (providing you have the PSU set to a low voltage.
Tips for collaboration.
Not everybody has to solder, have 3 people soldering, one putting in LEDs and bending pins, and one taping / cutting wires. (this is a vague ratio, most people won't be able to get 4 more volunteers, but just play with it.
Step 5: PCBs
Now time to populate and solder the PCBs. Everything is marked in the silkscreen, so there is very little to say here.
Now time to solder the PCBs to the Panels. There is a slot for Pin Headers in this board revision. It is quicker to solder in female pin headers and just put wires into that, but it is less secure (but secure enough for me). Just solder wires from the extra bits on the panel, and take them to the right hole. There is a list at dashroom66.com. REMEMBER, THEY ARE ADDRESSED FROM THE FRONT.
Step 6: Giving It Legs
Ok, I did timber T-bar stands, but anything will work, somebody suggestive tank traps, which is quite a good idea.
Anyway, of you want to go with my way (T-bar), then this is how you do it.
1. Cut a bit of 2x2 timber to the desired height, and a bit for the bottom (based on height, maybe about 1500mm ??)
2. Cut a MDF (or other wood board) into a triangle, reasonably large (this is all the structural support)
3. Mark the center of the small bit, and line it up with long bit.
4. Glue the MDF triangle to the timber, then screw the MDF to the timber
5. Paint it if you want to (can be bothered)
Step 7: Das Frame
This is where I had at my disposal a full workshop, and person who can actually make stuff, unlike me, who just goes to CAD. Most people won't have both of these, so I have posted an alternative method.
The way mine was done.
Mounts added to the side of the T-Bar stands, separated by the height of a panel.
Then we made 2 flat-bar crossbars, hooked onto the mounts, with wing-nuts holding it tight. We did the same for the bottom one.
Extra pieces of flat-bar were welded between them at the ends to stop it falling over (can be disassembled into the flat-bar rectangle and the two stands (plus the panels, obviously) )
Then we cut some small pieces of thin flat-bat, and bent them into hooks, and fixed them to the panels with a pop-rivet. The panels then hook over the steel frame, as shown.
Ok, if you don't have that stuff.
Just make the rectangle out of timber, with more vertical supports. Put screws into it and drill holes into the panels so that they will hook over. Put a bolt through the frame into the stand, with a wing-nut. I'd go with 2 on each side.
Step 8: Bringing It All Together
Put the frame on the stand (2 man job)
Hook on all the frames
Chain up the panels with the network cable (into the PCBs)
Add in the controller (An arduino uno with a protoshield, it's just a really really simple breakout you have to make, the table is on dashroom66.com, really, it's SOOOOOOO simple, just solder off some wires from some pins.
Run the software, and then just roubleshoot, you're done
We have a be nice policy.
Please be positive and constructive.