2 x 2 SMD LED Matrix – Revisited

Okay, I’ve revisited this light to lower the power and increase the life expectancy of the circuit. This was a pretty easy fix, really. 9V was too high, so I removed the 9V snap and replaced it with a 2 wire to Dupont female connector, then I took an unused USB cable from a dead mouse and gave that a Dupont male connector. The USB connected directly to the PC should give a supply of about 5.1V, that’s a 3.9V reduction (more or less) so the excess energy won’t go into the generation of heat.

2 wires connected to a Dupont female connectors and placed in a 2 pin block.

USB cable with two Dupont male connectors in a 2 pin block (also some heat shrink to make it a little tidier).
Both the male and female connectors have a little pointer in the case, on both sides, I’ve used this to indicate positive.

Circuit connected to USB with the Dupont connectors.

Drawing about 5.1 V, the light is still bright enough to read by and it doesn’t get very hot at all. Yes, it still generates some heat from excess energy through the circuit, but the temperature is MUCH lower, so the circuit shouldn’t burn itself out now.
To give you an idea of the amount of light coming from the circuit, I’ve covered the LED with my thumb and you can see the light passing through my thumb still. This is the same as when you put your fingers over a torch, the red light shines through (blood, apparently, soaks up the green and blue light spectrum, so red gets through as a red light diffused by skin, connective tissue, blood and ligaments).

Next, in the lifecycle of this little project, will be the mounting of the circuit in some semi-transparent resin … I guess that’s as far as I’m going to take this project. After that (or before that … who can tell?), I’m going to work on an SMD pulsing light circuit. I’ll probably go with the NE555 version of the pulsing light circuit. Anyway, that’s it for now. Enjoy!

2 x 2 SMD LED Matrix

Today my new 48W Soldering Iron Controller arrived in the post. For just $28.45 on eBay, this is essentially the same iron that is being sold elsewhere for up to $50. The iron came from Sydney, so I’m protected by Australian Consumer laws, so I didn’t feel like it was very risky. Turns out, I’m right. The soldering iron seems to work just fine.
I turned my hand to two projects with the new iron.
In the post today, I also got my new 16x2 character LCD “LCD HD44780 1602 16x2 Character Display Module Blue Blacklight For Arduino” that I also bought on eBay (for $3.42 AUD). The LCD needs to have some header pins (16) soldered in so that you can connect it up to a solderless breadboard. This was no problem at all with the new soldering iron. The solder flowed very well and the iron heated up fairly quickly. I’m happy about that. No pictures of the LCD yet, I’m going to post separately on that later on.
The main thing that I wanted the temperature controlled iron for was so that I could try my hand at some SMD soldering.
A while back, I posted an article mentioning the SMD version of a 4 x 4 through hole component LED matrix (4 x 5 LED PCB) where I said that I was going to have a go at SMD at some later date … well, today is the date.
The circuit is simply a rework of the 4 x 5 matrix using SMD instead of through hole components. Also … it is only 2 x 2 (4) 0805 Super Bright LED, rather than 20.

You can see that my soldering isn’t all that neat, but on a circuit this small, it is neat enough. There are 4 x Super Bright White LED and 4 x 120Ω resistors. The SMD form factor is 0805, so they are about 2mm x 3mm in size (more or less). I also have a 9V battery snap soldered in to the circuit. 9V is a probably a bit high and I don’t have much hope that the circuit will last very long before it burns itself out. After a minute or two of power, the circuit is uncomfortably hot, it may be that I can sacrifice some lumens and increase the resistor size to give it a more comfortable lifespan.
I wanted a small light that I could attach to my magnifying glasses to help illuminate my work. I plan to mount the light in a white resin plug to diffuse the light somewhat …now I’m concerned that the resin will not be much use if the resistors burn up. Meh.

When powered, the LED are indeed Super Bright.
While I was soldering the LED in place, the technique that I used with these fiddly components was:

1. lay the component down on the work mat
2. Using the multimeter, work out the correct orientation for polarity
3. Pre-solder the pad on one side
4. Hold the component onto the solder with some spring tweezers
5. Apply heat.

When the solder is hot enough to flow, the tweezers squeeze the component down to the board and the solder holds the component in place. After that, it was just a matter of soldering the other end down and then using some solder wick to tidy the job a bit.
I was thinking later that I could have used a small heat proof straight-edge to align the components in a more tidy way.
I need to get some more hydrogen peroxide and hydrochloric acid so that I can make another couple of boards, I’ve run out (pooh).
I’m still going to go ahead and mount the circuit in resin. But the next version of this circuit will use a smaller power supply and/or a greater sized resistor.
I need more practice at SMD hand soldering, but for now, I’m happy with the results.

MAX7219 – Experimentation – Driving 2 LED

After receiving my delivery of MAX7219-ENG chips from eBay, I’ve been struggling to understand how to use this useful chip. Most of the information that I’ve found on the Internet shows how to connect the chip to an 8x8 dot matrix display, which is great … but … I can buy the dot matrix display with a driver board (including the MAX7219 chip), so why would I want to?
Maybe my intended use of the chip is a bit wrong … but, whatever. It will probably do what I want it to do.
The goal with this bit of experimentation is to connect the MAX7219-ENG to two LED and to write a simple Arduino sketch to run the MAX7219.
What I came up with is as follows:

The Arduino is connected to the MAX via pin 9 (data), 10 (clock) and 11 (latch). I’ve also got 5V and Ground from the Arduino connected to the breadboard.
Pins 4 and 9 of the MAX connect to Ground.
Pin 19 connects to the 5V rail directly and pin 18 connects to the 5V rail via a 10kΩ resistor.
The two LED connect to the Digit drivers and Segment drivers.
Green LED connects to D0 (pin 2 of the MAX) to the cathode and SEG DP (pin 22 of the MAX) to the anode. The blue LED connects to D1 (pin 11 of the MAX) to the cathode and SEG A (pin 14 of the MAX) to its anode.
That’s pretty much all there is to it. Adding LED is a matter of Digit driver pin to cathode, Segment driver to anode. But that means we are really only driving a maximum of 8 LED per MAX7219. It would make more sense to build the LED into an array, but for this experiment, that’s what I want.

The above images show the Arduino Uno connected to the MAX7219 and 2 LEDS. I’ve taken shots from different views so that you can see how the project relates to the breadboard schematic above.
The sketch is pretty straight forward. Just remember that there is no array of LED to control, so we’re only interested in 0 and 1.

#include <ledcontrolms.h>
LedControl lc = LedControl(9, 10, 11, 0);

void setup()
{
Serial.begin(9600);
lc.shutdown(0, false);
lc.setIntensity(0, 8);
lc.clearDisplay(0);
}

void loop ()
{

for(int i = 0; i < 16; i++)
{
lc.setLed(0, 1, 1, false);
lc.setIntensity(0, i);
lc.setLed(0, 0, 0, true);
delay(30);
}
delay(1000);
for(int i = 15; i > 0; i--)
{
lc.setLed(0, 1, 1, true);
lc.setIntensity(0, i);
lc.setLed(0, 0, 0, true);
delay(30);
}

delay(120);
}

And, here’s the project running…

ARDUINO and MAX7219 controlling two LED

The sketch doesn’t do quite what I want it to do, but for the sake of the experiment … it works.

What I wanted it to do was for the green LED to cycle low to high and then the blue LED to cycle, kinda a glow and fade oscillation. I’m OK with it, I will spend some more time working out what I did wrong with the sketch sometime later.

Simple NE555 Pulsing LED – In A Box

Now that I’ve made the pulsing LED and soldered it all up on perfboard, I want to make an enclosure for it, ideally, one that diffuses the light and looks cool.
I have some 0.75 mm white PVC sheet at home that I’ve had for years and years (I used to use this for making table-top war-gaming scenery). The PVC sheet should be sturdy enough when it is glued into a solid shape and thin enough to allow light through and to diffuse it.
What I’m aiming for is, simply, a box to put the board in. I’ll probably use some hot melt glue to adhere the board to the PVC and I’ll cut a hole through one of the boxes walls to pass the power connector through.

When the circuit is powered, the light will pulse and the PVC will spread the light through it’s walls creating a glowing, pulsing box.
Last night, I cut the PVC and glued up all but one side of the enclosure (I’ve left the side with the power hole unglued) and I gave it a test run. The result was fairly pleasing … but quite plain.
I’m confident that the enclosure will do what I want it to do (glow and pulse). So, now I’m going to think about how to make it look Lovecraftian. The obvious approach is to cut up more PVC to make some faux pierce-work pieces to apply to the outside of the box. Alternatively, I could design and print out some black and white imagery and glue it inside the box. The thinking there is that the parts of the image that are black would prevent the light passing through the enclosure. Maybe a combination of the two.

Pulsing red LED in a custom PVC box. Now it just needs decorating.

I’ll return to this thread at a later date. I need to do some design work on the box to make it more worthy of being called Steampunk. For now … it’s just a glowing, pulsing box.

Simple NE555 Pulsing LED Perfboard

Following on from the previous post (Breadboard Version), I’ve soldered the circuit up on a small bit of perfboard (about 25mm x 35mm).
For this build, I’ve mostly used the bent leads of the components to join the bits together, along with a minimum of jumper leads.

I’ve placed the labels for the components as close to the component as possible … this is the under-side of the board.
As with the previous post … here is the top view of the board.

My biggest hassle with this circuit was that I forgot to link the input voltage to the collector of the transistor. I had a bit of a swear at myself for that, after I went over the circuit with my multimeter to give it a continuity test. I had rushed the build and I was totally ready to swear some more.
This version returns to the original design with a 100 uF electrolytic capacitor. I ran the solderless version for a while last night and decided that 100 uF was better. Oh well, you live and you learn.

Perfboard version of the Simple NE555 Pulsing LED

The video just shows the circuit with power, going through a couple of cycles.

Simple NE555 Pulsing LED Breadboard

Here’s a simple pulsing LED circuit that I found online (by MrBeta)
I’ve made some virtually unnoticeable changes to how Mr Beta describes the circuit on his instructable, however, I hope that the photographs and video are more clear. I have had some trouble with this circuit and I’ve usually abandoned it after a couple of minutes.
This time, however, I persisted and worked it out.
Initially, I was after, pretty much exactly, this effect. A simple pulsing LED. The idea was to use this circuit within a Steam Punk prop (such as in a ray-gun). This component was going to be part of more LED jiggery pokery and I had moved on to achieving something similar as part of an overall Arduino controlled LED array (multiple LED doing various things simultaneously). Anyway, I’ve been thinking more about this circuit and, since I have a bunch of SO8 555 chips, I’d work on making this with SMT rather than through hole … another planned exercise for when my SMT LED and Resistors arrive (oh, and I’ll have to get some SMT transistors and capacitors).
The project requires:

• NE555
• 33k ohm resistor
• 470 ohm resistor
• 33 uF capacitor
• LED (I’ve used spooky green)
• 2N2222 NPN transistor

I’ve put this together on a solderless breadboard and photographed it from every angle and put some labels on the pictures to make it easier to reproduce.


And here is a video of the pulse. MrBeta used a 100uF capacitor, but that was a little bit too slow for what I wanted. The 33 uF capacitor gave me a much more satisfactory cycle.

Simple Ne555 pulsing LED

Anyway, that’s it for now. have fun!

LED Desk Light – 4 x 5 Matrix – PCB – Part 2

I’ve completed the etch of my 4 x 5 LED Matrix PCB and there are two gaps in the circuit.

The trace gaps are marked with red boxes. The gap in the negative trace was found using my multimeter using the continuity test function and verified visually. The gap in the connection from the LED cathode to the resistor can be plainly seen. This gap was where there was a missing trace in the laser printout that I “fixed” using the permanent marker, clearly, the marker wasn’t permanent enough. I think that it would have been OK if I had gone over that resist line a couple of times. Well, that’s a good lesson for me.
To fix the break, I intend to over-solder the negative trace gap and to solder in a jumper on LED 8.

My next task will be to drill and solder in the power at the bottom right of the PCB and then connect LED 1 along with it’s resistor. That should be proof enough that the trace is working.
After that, it will be a matter of plodding on with the remaining LED and resistors.
Now that I’ve populated the PCB and given it power … I can see that there were some other problems with the traces. LED 11 and 16 are non-responsive. When I test them with the multimeter, they respond, but not when the board is powered. Oh well … it’s a prototype.


With that done … I’m going to try another board and see if I can work out the bugs in the traces before I populate it. What a pain in the butt.
I’m going to order some SMD resistors and LED and get on to the SMD version of the 4 x 5 LED Light.

LED Desk Light – 4 x 5 Matrix – PCB – Part 1

Now that I have completed the perf-board prototype of the 4 x 5 LED matrix, it’s time to start work on the printed circuit board version.
I’ve laid the board out, pretty much the same as for the perf-board version, although I want to try something slightly different with the positive and negative traces so that I don’t have to use any jumper leads to do the column joins.
The new layout is below

The above is the bottom layout in mirror reverse. You can see that all of the positive traces connect at the bottom of the columns and the negative traces connect at the top. It’s no longer simply a bent parallel line of LED, but an integrated parallel circuit. I think that this layout will work, theoretically, but I’m not sure if it will, practically. Note the missing trace in the middle of the board!
I also found out that I can make Fritzing lay out the resistors in a horizontal alignment by changing the pin spacing … simple, really, and something the Fritzing team already though of.

This makes the Fritzing layout very similar to the perf-board layout.
I’ve printed the bottom layer out and transferred it to my single layer F4 copper clad board.
The transfer is OK

although it is a little bit … bitty. I still need to print this out on some decent paper. However, with the traces “mostly” there, I can go over the circuit with my trusty permanent marker.

Using a ruler and reading glasses, it becomes better.
The pads are probably a little bit blobby, but that’s OK too. This is still just a prototype. I think I need a finer permanent marker … or better eyes.
From here, I’m going to etch the board. But that’s a job for tomorrow night.

LED Desk Light – n x n matrix – Je suis fini

Yay … I’ve completed the LED Desk Light 5 x 4 matrix!
That wasn’t so hard. Well … now that I’m sporting a bright shiny new pair of +3 reading glasses (for the princely sum of $15AUD).
The reading glasses made the soldering very easy. Much easier than the desk magnifying glass. I was finding that the focal length of the magnifying glass was too short, and so, the depth of field/operating space was much too limited. The reading glasses give me a much better nose to soldering iron length.
Anyway, enough of me whining about my aging eyes and on to the show and tell.
The main action takes place on the underside of the perf-board.

As I described in the previous post (here) the matrix is really just one parallel run of LED and resistors. I’ve linked the LED anodes with red jumpers and the resistors with black jumpers. The 2 pin header is at the top right of the perf-board and the series runs from there to the left, then down and to the right, down and to blah, blah, blah … as seen in the following image.

Soldering the jumpers on was a little bit of a pain, the distance between the leads is fairly small so a) stripping the wire was annoying and b) holding the jumpers in place with alligator clips was a pain. Still … all done now, I can move on.

The top side of the perf-board is much more attractive. All of those 5mm LED and their resistors all aligned nicely in a grid. Very nice and uniform. Just to the right, you can see the 2 pin header and the 2 pin Dupont connector that I made up for the 5.7V AC Adaptor. I’m pretty pleased with the adaptor modification. I may have to do a little re-work on the circuit to include a switch, but that can come later. You can also see how the resistors worked out using the paddle pop stick as a bending jig, and also in the horizontal alignment.
Finally, you want to see it all lit up, right? Well, here it is.

All lit up like candles on a birthday cake. It is quite bright but only has a 25^o viewing angle. I’m thinking about making a project box with an opaque white cover to work as a diffuser. That should work.. I also need to think about how to mount the light on a stand so that it casts it’s light down (or up if I want). Again … later.
All up, I’m happy with the prototype and I’m going to start planning the SMT edition of the light. All I need to do is find some suitable (and cheap) components on eBay. On reflection, I think I’ll use the 0805 rather than the 0603 it’s enough of a difference in size to make it easier on me and still small enough to make it worth while.
Oh and … in case you are wondering, the perf-board is 50 x 70mm in size.

LED Desk Light – n x n matrix

I’ve decided that it’s too dark at my desk using just the overhead light for illumination. Hell, I’m getting old and my eyes aren’t much good in the dark anymore.
What I’m building is a very simple matrix of LED lights soldered to a perf-board. The idea is very simple, a matrix of LED connected in a parallel circuit that kind of snakes around to make a 5 x 4 (20) LED configuration.
I’ve designed a simple 2 x 2 LED circuit that I will simply extend in both the X and Y axis to make my 5 x 4 circuit. The circuit was designed using Fritzing.

I’m only using this as a design guide, since I’m going to be making it up on perf-board rather than PCB, and I’m orienting the resisters vertically, rather than horizontally to conserve space on my perf-board. The main reason for that is that I want to set my board up in as little space as I can (with a reasonable amount of space, that is) and using through hole components.
The circuit uses 20 x 5mm Ultra Bright White LED, 20 x 150 Ω resistors (120 Ω is the right size … but I don’t have any of them) and 2 x 90^o pin headers to attach to power (a 5.7V AC Adaptor). I used a LED Design Wizard (http://led.linear1.org/led.wiz) to help me to design the matrix based on the properties of the LED that I am using (Forward Voltage = 3.3V, Forward Current = 24 mA and a source voltage of 5.7V AC).
Later on, I’m planning on making the same thing using surface mount technology (SMT) with 0603 components.

That’s going to be a bit of an adventure in surface mount by hand for me. I’ve never done any SMT stuff before and this is a simple enough circuit. But that’s for later (I still have to order the parts, and then wait for up to a month for them to arrive).
So far, I’ve soldered up 4 LED and 4 resistors. My LED are spaced about 5mm above  the perf-board and I’ve made myself a spacer that will allow me to position the LED consistently above the board. The spacer is nothing more than a paddle pop stick that I’ve cut down to size. The spacer fits between the LED legs and, when I’ve bent the LED legs, the fit is snug. The spacer allows me to orient the LED rows while I’m soldering and then (with a little wiggling) I slide the spacer out and use it on the next row. I can also use the spacer to set the resistors up, too.
Now that I’ve done the first 4 LED (2 x 2), I can see that I should have started the first row off one row in from the edge so that I can better accommodate the column jumpers. I’ve also noticed that the silk print on the cheap perf-board is not very well laid out. The grid is 5 x 5 then 5 x 6 then 5 x 5 so it doesn’t end up even. Oh, well … I’ll survive. It just looks a bit wrong.

Above is a picture of the LED matrix showing one row of LED aligned using the spacer. This is how the LED legs will be bent evenly so that the LED are all set to the same height above the perf-board.

And here is a view of the matrix showing the 4 LED that have been soldered to the board. These 4 LED were soldered without the spacer (before I had the idea to use the paddle pop stick as a spacer, at least). You can also see the silk screen grid on the perf-board a little better. Let’s play “Count the Holes!”. The horizontally aligned resistors save me a little space.

Finally, here is the under side of the perf-board showing the beginnings of the solder grid. The height of the LED above the board has the advantage of setting the length of the leg under the board to the anode of the next LED in the column. This makes it a little easier when I’m soldering and I don’t have to cut any of the anode leg off. The cathode leg of the LED is a different matter, it gets soldered to the resistor and then chopped off. I’ve bent the negative side of the resistor so that the leads from the resistor forms the negative line. The positive and negative  columns then get connected to the next positive or negative column, respectively, with some shielded jumper wire … but we’ll get to that later.
When soldering the LED into the perf-board, I use a heat sink clip on the upper side of the LED to avoid overheating the component. I start by heat sinking the unsoldered anode and then soldering the anode from the previous LED to it. The solder has some trouble forming a good fillet, so I leave the iron against the copper pad and make sure it gets a decent amount of solder flowing in. Some of my soldering is a little messy, but, hey … it’s a prototype, so I can cope with it.
When the anode is soldered, I then solder in the cathode (with the heat sink attached on the other side) and clip the lead where it will intersect with the lead from the resistor. Then it’s a matter of soldering the resistor in place, cutting the crossing lead from the resistor (the one that attaches to the LED cathode) and bend the other lead down into it’s column.
So far, so good.

LED Lamp – Part 5

Today, I de-molded the lamp head from the plasticine.

There was some cleaning up to do as some of the resin leaked through the CD and made a mess on the under-side of the lamp. This would be visible, so I wanted to make it look better. It would also make it difficult to attach the disc to a riser. I picked the resin off with a sharp knife and an awl.
The cast wasn’t 100% successful as the mold was not sitting flat in the ice-cream container. The disc is about 13mm on one end and 10mm at the other side … meh.
Then … I connected it to the USB power supply (5.1V) and it looks pretty snazzy.

It throws a decent amount of light too.
With the disc turned over, so that the LED are facing downward, it looks pretty good too. The clear CD acts as a bit of a light-pipe, the cast blue light is pretty satisfying and the light coming through the resin looks nice too.

I need to figure out how to attach it to a riser and stand. I was originally thinking of casting a riser using the resin with the wires passing through the middle of the cast. That would involve pouring half of the mold, letting it set a little, laying a tube through the centre of the riser and then filling the mold with resin. I should end up with a riser that has a void in the middle where I can pass the wires through. Then I was thinking of making a base with a switch in it that would hold the disc and riser.
An alternative idea is to affix a clip onto the disc so that the light could be clipped on to a shelf over the bed. For that I’d need to make a small switch enclosure.
I dunno what to do … but I’m thinking about it.

LED Lamp – Part 4

The next thing to do is to invest the circuitry in some resin. I’m using Barnes Easy Cast Clear with a mixture of red and white dye and some glitter to add some pink glittery specialness for my daughter (the lamp is for my daughters bedroom).
First, I made a mold using plasticine.

I redid the plasticine base, pushing the LED lights through the CD and into the plasticine. That way, the LED plug up the holes in the CD and there shouldn’t be too much leaking underneath the disc.
The plasticine was rolled out into a couple of strips that were then wrapped around the CD to give me a vessel to pour the resin into. I made sure that I sealed the seams in the plasticine so that the resin doesn’t leak there either. The two wires (positive and negative) that power the circuit were cut in through the plasticine wall and sealed up.
I made up 100ml of 2 part resin. In the first 50ml, I added the white and red dyes and the glitter. The colours and glitter were added here so that I could mix them in without worrying about the pot-life of the mixed resin.
I put the plasticine reservoir into a plastic ice-cream tub to make sure that any spills or mishaps were contained.
When I had the colour mixed thoroughly, I then added 50ml of the resin part-B and poured it into the plasticine reservoir.

The mixture is curing in the mold.
You can see some of the glitter.

The resin is about 15mm thick and should cure to an almost opaque pink.. I’m not sure how much of the glitter will be visible, I’m hoping that the light from the LED will illuminate the resin disc.
Well … here’s hoping. The MSDS for the resin says that it is cured in @1 hour and takes about 7 days to fully cure (unless you want to bake it in the oven … not practical here, I’m afraid).

LED Lamp – Part 3

The next thing to do is to solder the anode (+) side of the circuit.
I cut the shielding off the solid core wire so that I would have more flexibility when soldering … also, cutting out little soldering windows is not so easy.

This was a bit of a pain as I had to mark out each solder point on the wire, take the LED and resistor out of the plasticine and position the wire and LED on my soldering stand. Each time, I had to put the circuit back into the plasticine and mark the next solder joint. Still, with a little patience, I got there.

You can see the termination on the right hand side of the loop and I’ve let the wire trail off.
More wire stripping for the negative side of the circuit. I also cut the long end of the resistor leg down to a more manageable (approx.) 5mm length. Then I was able to solder the outer wire in to the resistors in place. It wasn’t necessary to use the soldering stand for this side because I didn’t need to be too careful about heat-sinking the resistor.

Once the outer wire was soldered in, I took the plasticine off the back, cleaned the plasticine residue from the CD and presto … the CD is all wired up.
Next is a quick test of the circuit to make sure the LED all light up and we are pretty much done with the light end of the build.

I also drilled two more holes in the CD near the perimeter for the two solid core wires to go through to the under side of the CD.
Fiat Lux … let there be light.

LED Lamp – part 2

Today I got to work on soldering up the LED.
I made a bed of plasticine to sit the LED in, this was done by rolling out some plasticine about 10mm thick and sitting the CD on top, then I pressed the LED into the plasticine through the holes that I had drilled through the CD.

That gave me a stable surface to work on where the LED are spaced properly.
Then I took each LED in turn and shortened the cathode (-) leg and soldered it to the 100 ohm resistor.

I used my modified USB cable to test each of the LED as they were soldered, to make sure that the LED was still working (I’ve burned some LED out by being sloppy with my heat dissipation before).

As the LED/Resistors were completed, I put them back into the plasticine so that I could see how I’m going for space.

I’m still going to have to shorten the legs on the resistors, but here is the build so far with the cathode end pointing in to the middle of the CD.

And here it is with the cathode pointing to the edge of the CD. I need to run a wire between each of the resistors in series. I’ll also need to run a wire between the anodes in series. I think that I prefer the cathodes pointing out, but I’ll need to see how I go when I wire up the positive lead.
Anyway, that’s the progress so far. I’ll do some more later on today.