Bit more soldering

Soldered three more pillars yesterday, and did another eight tonight. On average it takes around 11 minutes to solder one pillar. Not bad. Only 2 mistakes in the last batch: one LED was inserted into the jig incorrectly (or I marked the wrong lead) and one bad solder joint.

Here's the result of my labor so far:

24 done, 40 more to go.

Stackable!

Received a bunch of spacers today (HTS-310) and they fit the cathode boards perfectly.

The whole construction feels pretty solid, very little flex. That's a good thing, since putting in the cables requires quite a bit of force. Speaking of cables, that's one more extra time consuming job...

Not much time spent on the cube lately. I'll probably be able to find a couple of free hours this weekend (yay for second Easter day). I did spend some time on some other stuf.

That's more like it!

So I'm done with bending leads on those LEDs, in multiple ways... I've done about 500 now and am calling it quits. I'll bend the rest when I need them.

It's finally soldering time again! Six done tonight in a bit over an hour. Average soldering time for one pillar is now about twelve minutes instead of twenty. Not having to bend those leads before putting them in the jig really makes it go a lot smoother. Anyway, 13 down, 51 more to go...

Soldering also seems to go faster, I think I'm getting the hang of it :)

Moar LEDs!

Phew! 400 done, just a bit over 100 to go until I have 512 perfectly shaped LEDs. That's one bag and a dozen :)

Bending LEDs

Another weekend well spent :)

I've soldered three more pillars and straightened around fifty wires. I've also started bending the leads on all LEDs, a really boring job, but doing this beforehand will make the soldering go much faster. As it turns out, bending one LED costs about as much time as soldering one. And the more I can do in batch, the better!

Here's what I started with: around 600 LEDs

And the result after an evening on the couch, watching TV while bending leads.

200 done, 400 to go :)

I've marked the green cathode with a marker on each LED, that lead will have point up when the LED is inserted into the jig. It's pretty easy to spot the correct lead by just looking into the package, but more on that later.

All leads are at a 90 degree angle of each other and the LED sits perfectly flat on a flat surface (my hand isn't flat obviously).  It takes about 30 to 40 seconds to bend the leads on one LED, I could've done this faster but I'm a bit of a perfectionist, and I was watching TV :) It costs about 1 hour per 100 LEDs, but hopefully it'll save some time when soldering.

The great thing about this project is that it's easy to spend anywhere from 15 minutes to a few hours on it; you can just grab a box with all the tools/parts, do some work, and put it away when you're done or out of time. Cleaning up and getting started only takes a minute or two.

In other news, the PCBs I've ordered have been shipped last Friday! They'll probably arrive somewhere next week, but at least before the end of the month :)

Update 17-03: and a few more LEDs done, halfway there!

Cutting and stripping the time away

2.5 hours well spent. I've cut and stripped about 150 wires. I guess I still have a few wires left to cut and strip, but I'm not going to count them right now. I guess I'll find out when I run out of wires :)

I also just learned that the order for my boards have been sent to the fab. It's expected to arrive at OSH Park in about a week, not bad :)

4 down, 60 to go!

This project is going to take some time... I've just finished the fourth pillar and did some timing. I first cut, stripped and straightened 24 wires (for eight columns). This took about an hour, 7.5 minute per pillar. Then I started building pillars.

• Bend the legs on eight LEDs
• Trim the leads on the LEDs
• Insert them in the jig
• Insert the wires
• Solder the LEDs
• Trim the leads on the LEDs further
• Cut the wires
• Take the pillar out of the jig
• Test it using the test jig

That took well over half an hour for the first pillar, 30 minutes flat for the second, and 20 minutes for the third. I did things slightly different for the last pillar. Instead of trimming the leads after bending them I just inserted the LEDs in the jig. I start by slightly pressing the top wire down on the jig and trim the top leads (green) before soldering them. Then I solder the top leads. After that I trim the remaining leads (red and blue). I then slightly bend the leads so they (almost) touch the wires. This makes soldering a bit easier, and you don't risk damaging the solder joint when trimming the leads.

All in all it takes about half an hour to create one pillar. I must admit I'm not that experienced when it comes to soldering, so I might be able to shave a few minutes off on that. It also helps to do things in batches and minimize switching between tools; I've first cut 24 wires, then stripped them and finally straightened them, instead of performing 3 steps on 1 wire after another.

Anyway, at this speed it's going to take about a month to finish all the pillars if I spend one hour a day. Damn...

Jig: Mk. 2

Sunday afternoon, a perfect moment to spend some time in the man cave :)

I decided to build another jig, since the first one is, well... crap. The main reason for that are my lack of skills. Fortunately there are plenty of tools to compensate for it, and my old man has a shed full of 'em :)

Starting with a nice jig to compensate for my horrible skills with a saw (it even says "no skills required" on the box, perfect!)

 Finally, 90 degree angles! I decided to make the columns in the jig 10mm deep, that will leave 15mm of space left for putting the LEDs in. I want the columns to be about 14mm wide, so there will be around 11mm of space between the LED pillars when they're installed. Unfortunately the wood is 22mm thick. Sawing that off would be a pain in the behind, so enter tool nr 2:

Yes, it's an electric planer. At the highest setting it turns 2mm of wood into a large pile of dust. So after using it four times I end up with a 14mm wood instead of 22, and a work bench covered in wood particles. Nice.
Back to the hand saw, 8 columns of 10mm done. Time to put some holes in them.

Since they're 14 mm wide, I've drawn a line 7mm from the top, and a vertical line right in the center. For the drilling, enter tool nr 3:

It's my trusty Dremel in the Dremel Workstation. Perfect for drilling some perfectly vertical holes.

Spot on, right through the center! That's just a 3mm drill, but the hole needs to be 5mm. I enlarged the holes using my cordless drill. The existing hole will guide the larger drill, so the hole remains in the center.

Then it's simply a matter of drawing a few lines on the base plate. The lines are spaced 25mm apart and there are two lines crossing them to mark the sides of the colums. Those are 14mm apart and 15mm from the edge.

Add glue, apply pressure. This is the fast drying type, takes about 15 minutes to cure. Tightening and loosening the clamps needs to be done carefully. Add the center clamp first, then the outer ones. Don't tighten them completely right away, but tighten each one a bit and move to the next. Removal is done in reverse order (center one last).

In the mean time, I created a small jig for bending the LED's legs.

Simply insert the LED, bend the legs, and press another piece of wood on top. Easy! The front and back plate are done as well:

The outer holes are 14mm apart, the center hole is 7mm above the outer holes.
After the glue has dried, it's time to drill a couple of holes from the bottom into the colums. Again, I used the Dremel for this to make sure the holes are perfectly vertical and spot on down the center of the colums.

Let's put in some screws. It's important to put a load of pressure on the columns so they won't start to rotate when you put the screws in. Clamping the whole thing down seems to work pretty well. The front and back plate had the same treatment.

And after about 3.5 hours it's done! Let's put in some LEDs!

 Nice! Works like a charm, now let's cut the three wires so we can pull the pillar out of the jig.

No problems there, plenty of room!

That's usable, may need a bit of bending, but not bad!

And it works!

Compared with the one from the first jig (at front). The space between the LEDs and the cathode wires has become a lot smaller (20mm to 14mm) and the distance between the LEDs has been reduced from 30mm to 25, awesome.

The next step is rigging up a framework to test a pillar. I'll probably just use one shift register to turn on each anode sequentially while sourcing one of the cathodes. After cycling through all anodes it'll move to the next cathode. So it'll first light up all reds, then all greens, then all blues and then all reds again, all in a matter of a few seconds.Guess I'll wire up an AtTiny on a protoboard to make it a semi permanent setup, I just need to get my hands on a dozen alligator clips :)

Creating a jig

Probably the most important tool when constructing the cube is the jig. It hold the wires and LEDs in place when you solder them, making life a whole lot easier. This jig is used to create a pillar of LEDs; 8 LEDs stacked on top of each other with all their cathodes connected.

I've bought a piece of wood, about 44 mm wide and 20 mm thick, and cut it into pieces. I've cut off eight pieces of 20 mm to hold the LEDs, and two pieces of 80mm to go on each end. The bottom part is about 250 mm. In the 8 "columns" I've drilled 5mm holes, 1 cm from the top. The distance between the hole and the edges of the columns determines the distance of the wires to the LED.
I've drilled three 3 mm holes on both ends to hold the wires. The position of these holes should match the top and sides of the columns, so the wires will touch the columns.

This was just a prototype I made to figure out the what works and what doesn't. I recommend taking your time for designing and constructing the jig, as it will eventually determine the quality of your cube.

Plan your cube; think about how large you want it to be. I'm going for a 1 inch spacing between all LEDs. This means that the front of a jig column should be one inch away from the front of the next and previous  jig column. The width of the columns shouldn't exceed 20mm, this leaves just 5 mm of space between the pillars of LEDs. As you can see, the design of the jig determines the dimensions of the cube. And make SURE you keep plenty of room between the bottom LED and the end of the jig, you'll need this extra wire to install the pillar.

Things that went wrong:

• I'm not that great with wood, I used a hand saw and a portable electric drill. The result is far from perfect. Next time I'll use an electric jig saw for cutting and my Dremel workstation to drill straight holes.
• Use glue. The columns rotate a bit, so next time I'll glue them first, then drill holes from the bottom before screwing them in place. This should keep them perfectly in place.
• Make the columns thinner. The space between the columns is a bit too small to comfortably put the LEDs in and out; they tend to get stuck.
• Make the columns narrower. Right now I'm creating pillars that are 20 mm wide, I think I'm going with 12 or 15 mm instead, so I'll have more space between the pillars.

 Here's the result of my first test with the jig:

 Not too shabby. I had to put quite a bit of force on it to get it out of the jig so it's a bit bent. A few more lessons learned:

• Make sure you have plenty of clearance between the columns, one of the LEDs got stuck.
• Make sure you bend the legs of all LEDs equally, or they might push the wire away making it difficult to solder other LEDs. I'm probably going to create a jig for bending the legs as well.
• Place the LEDs before you place the wires, it's much easier that way.
• When done, cut the wires at the top of the pillar first, then pull the pillar back so the LEDs are freed, then cut the wires at the bottom of the pillar on the outside of the jig, this gives you another extra cm of wire.
• Straightening the wire is done by inserting them into the jig, tie their ends together and rotate the bunch. This will put tension on the wires and that will make them nice and straight. Don't put too much tension on them or they will break!

And a few things to keep in mind:

• Test your LEDs before you put them in the jig, make sure they work and that the brightness is the same as the others; you really don't want to replace a LED when your cube is already constructed.
• You can use a wire stripper to strip the wire, but I like to use a snap off knife. Just place the wire on a surface, place the knife on the wire and hold it almost parallel to the wire, then gently pull the wire along the knife and half of the insulation will be stripped away in one go. You can peel the other half off easily.
• The wire I got is pre-tinned, and it looks great! Much better than bare copper in my opinion.
• You can straighten the wires a bit before inserting them in the jig. Use two pliers to grab both ends of the wire, then tug on them gently a couple of times. Don't do this too hard or too often because the ends will suffer from metal fatigue and break.
• WASH YOUR HANDS! You're not going to get lead poisoning from breathing fumes, only lung cancer. But the lead does get on your hands, so make sure you wash your hands thoroughly before you eat, drink, rub your eyes, scratch your <insert bodypart>, etc. Also clean your working surface and don't put food on it.
• Don't breath the fumes, it's not exactly healthy. Using a small 12V computer fan is enough to blow most of the fumes away from you. Keep your mancave/shed/living room well ventilated.

That's it for now, once I'll have my final jig done I'll add another post on this subject.