Tuesday, July 17, 2018

DIY Synth and Electronics Pseudo Silkscreening using "Lazertran"--How To Do This!

I am still trying to figure out how to make low-cost, low quantity, high quality front panel silk screen art but can't solve that one out.

And: I have tried etching/fabrication services like Front Panel Express but find their CAD tools difficult to use and their services expensive for one-offs.

The good news: I have been using a water slide decal process to get me close to silk screen type front panel finishes using something called "Lazertran".

That's what this post is about. No, I don't work for these guys. This isn't an ad but is the best way to do this I have found to date.

So if you already have your metal work and want to get close to professional looking, one-off front panel art,  for about $1-$2 USD per panel, please read on.

Still with me?

First, go out and get this stuff: "Lazertran."  You can find it online direct, also at Blick Art, Amazon, and several other online suppliers.  Your local art store may also have it, or maybe can order it for you.

There is one Lazertran version for laser printer and another for inkjet. I only have tried this with the laser version. You can get legal sized sheets or 11 x 17 but here I use 8.5 x 11. I'm interested in knowing if the inkjet material works the same way as described below, if you know I'd be grateful for comments.

Before we go on: be safe! This process involves putting metal into an oven and cooking it for a few hours. I probably don't need to go over safety tips but will anyway--you have to be sensible or you wouldn't survive a week of DIY.....So please, don't be a bozo about this.

E.G.: Don't clean the panel with gasoline then put it in your oven. Don't touch really hot metal with bare fingers.  Don't use a chainsaw or small explosive device to open your stove door--just pull it open. Don't put plastic front panels in your oven (they will melt, burn, and stink up your house). And above all, never, ever listen to Barry Manilow's "I Write the Songs" in spite of how damn catchy it is.

Nuf said??



You will also need:
  • The metal front panel you want to use, ready to go. If you've painted your metal panel, make sure it will withstand a 300+ degree oven bake. So, high temperature paints, like those used for car engines, are best. I leave figuring out the right kind of paint to you.
  • You'll need an oven that goes to 300-350 degrees F. Most of us have those, or use mom's? Whatever. I imagine toaster ovens will do as long as you can control the temperature.
  • Scissors to cut out the decal. 
  • Computer software to design, modify and flip your decal--Adobe Illustrator is what I use but there are lots of programs for two-dimensional artwork.
  • Tongs or BBQ implements to handle your panel when it's hot.
  • A credit card for smoothing out tiny bubbles
  • 800 to 2000 grit wet/dry sandpaper.
OK let's go:

For Lazertran to work, the front panel has to be extremely smooth--the decal with tear and hang up on any burrs or rough edges, form bubbles, and look crappy. Also, make sure your panel is clean; the decal won't stick to oil and dirt.
Next this may be obvious, but: take careful measurements of your cleaned up panel. If you mess up your measurements you will have printed a $2USD Lazertran decal that won't fit your panel, and we don't want that.

If you really don't want to measure things: I have used a Ricoh flatbed scanner to scan a 1:1 image of the front panel(s) in question; then used the PDF output from the scanner as a background in Adobe Photoshop. Before printing I hide the background layer. As long as the original scan is really 1:1, this will work.

Another way: I first draw the front panel in a CAD program (Eagle in my case) to create a down-to-the-millimeter drawing of anything that needs panel art. Save it as PDF and then use that as the background in Illustrator or whatever graphics program you use.

Eagle BRD file of a Fracrack 2u panel

Illustrator will open PDFs and allow additional artwork to be easily added on top of the PDF background. I figure other graphic art programs will do the same? If so, the PDF background becomes an easy way to make sure the decal lines up with the panel since it's a 1:1 match. As long as the elements you see in the background are holes, drills, dimension layer outlines, and mills, they won't show up in the final panel, but can be used to design and align the decal.

About color decals: If you are doing a color panel you're in territory unfamiliar to me, I only do B&W, but keep in mind that almost all lasers and inkjets can't print white. They assume the background is white and treats white artwork as clear so it can "show through". I imagine from model making that other colors may appear a bit faded or washed out if it's like other water slide decals I've messed with. Just a guess.

For this tutorial I am fabbing a new one-off panel for a Triple Moog-like VCA clone for which I did a PCB board design, as well as the GCS/EFM/everyone-else Norton 3900 amp based Serge Waveshaper (hence the Serge logos--give 'em credit where it's due--this is a really cool bit of electrical engineering on Serge Tcherepnin's part--you can get details, boards, gerbers etc. for it everywhere, my version is here
Here's what I ended up with in Illustrator for the Serge module:


Before printing to your Lazertran decal paper, check your printer settings, print out a 1:1 of your  artwork, and lay it over the panel to see if everything lines up--you want to do this with normal paper before committing to Lazertran.

Here I've done that with cutouts of standard 8.5 x 11" paper--yep looks OK.



Now go back to your art program, select all the elements in your design and flip things, so it's 180 degrees flipped along the Y axis, like this:


Save the flipped file--we are going to need to print the flipped decal image to Lazertran.

Here's a semi hidden secret. You have to BAKE THE DICKENS out of the Lazertran sheet before you take the decal off the backing. Otherwise your decal will bubble during the baking process. The instructions say to use a heat gun for this pre-bake but that's never worked for me.  I have had to literally hold my nose and bake the decal sheet in my oven before I apply decal to metal.

For this pre-bake-your-decal-sheet process, preheat your oven to 200 degrees F and then put in the decal for about 5 minutes.  

 As the decal bakes you will smell a gross plastic burning smell. And when you take out the decal paper it will look like you tried to BBQ it:




The good news is--I learned this by trail and success??--the decal will still look OK even though the backing paper got charred. But you can overbake the sheet....then the decal won't come off, so keep checking on your decal during the prebake.

Next, cut out the decal along the panel lines:


…..and soak each decal in warm tap water for about a minute--less if you can. Warning: if you soak the decal too long the laser print may start to disintegrate.  I have seen this on occasion, but other times I have left the decal in the water for 5 minutes without issue. No idea why.



I didn't get a photo of this, but apply the flipped decal face down to the front panel by sliding it off the backing and onto your front panel.  

Line it up carefully.....

Now you've got to get rid of the air bubbles that invariably live under the decal you just applied. 

I have tried all different ways to "de-bubble" but the best way, the way I always come back to, is use my fingers to get the big bubbles out, then gently (!!) use a credit card edge to wisk away all the smaller bubbles. You will probably have to re-position as you go, that's not a problem, be gentle so you don't tear the decal.  

Again no photo for this--I was too busy trying to not ruin the decal and get rid of all the bubbles. But with a gentle touch it's not a problem.  

Hold the panel up to a light and see if you can see bubbles under the decal. If you can still see bubbles, gently repeat the process.

Last step before the bake, take a napkin or paper towel and carefully dab off whatever water remains on your panel. Then check for air bubbles again.

Once you're bubble free it's time to bake the decal onto the panel.   

With the oven still at 200, put the decal in there for 5 minutes.  Important: After 5 minutes remove your panel with tongs, and check the panel and make sure bubbles haven't formed.  If you have bubbles at this point you can quickly touch them to flatten the bubbles or pop bubbles with a pin, but in my experience after about 10-15 minutes the bigs ones are here to stay.....so set your timer and do this check.




(I have done Lazertran bakes in a pan, on tinfoil--I can't see any difference, so do whatever is easy..,) 

After the five minute check, and maybe another check at 10 minutes, you're past the bubble popping stage.  Keep the panels in the oven for another hour.  

Then increase to 225 for an hour (if you are impatient, half hour will do, but the more time you bake the better the decal looks at end), then 250 for an hour, then 275 for an hour.  At this point, you might see tiny bubbles in the decal, but they will bake out if you're patient. OK, finally 300 for an hour.  Don't go over 300--the decal might burn if you do.  Not 100% sure about this--I have gone to 350-400 without issues, but other times not. 

When this is done, remove the panel with your tongs. After your 4+ hour bake, if everything went OK, you end up with a pretty good looking panel, not quite pro silk screen looking, but really super close.  

And after a full bake if all went well, the finish is really baked on--I have had difficulty removing the decal with 500 grit sandpaper.  Yeah it's on there!

For clean up, you may need to take an X-acto blade and get rid of any remaining decal material that's sitting over a drill, outline, or cutout.  But for me after a few hours most of the decal that went over holes and milling has baked all the dookie off and any remnants are long gone.  

And....if you did end up with bubbles, you may be able to sand them off.

To finish things, I use 800/1000/1200 grid wet n' dry sandpaper to gently sand the panel to give it a more uniform look.  Don't be too rough--especially with the 800--but if you baked the decal on for hours it should withstand a lot of abuse.

Here's what I ended up with while doing this blog post:

OK that looks pretty good I think! 

We're now ready to finish things.  Bolt on the PCB, mount pots, knobs, etc.

Here is how my Serge Waveshaper clone looked when I was done.


Not too shabby?  You can get very fine details out of this process--the "1", "2", "3" by the jacks is 6 point font and is fully legible, and the "normals" illustration below the gain knobs is even smaller but came out just fine. You get the idea.

One  more hint:

If you're in the process of fabbing your panel, you might try experimenting with baking on the decal following the process above and then drilling out remaining holes and mill work.  

As long as you drill and mill carefully--a skittering drill bit will tear the decal, screw up your panel and possibly injure you--this works better than drilling/milling then applying Lasertran.  You can add x marks to your decal where you need to drill....this helps with panel symmetry and drill placement.  

OK that's it for now, give it a try and let me know what you think.  I am always working on improving this process.  Thanks.

   







Friday, July 6, 2018

QUICK ONE: Super Microvcf--8 components?

Quick one--

I am on a quest not sure why to find a VCF with the lowest parts count.  I could get one of those one Curtis chip clone solutions but that's cheating?

I created a long time ago a Vactrol VCF that's pretty low but I may have beaten it here....

I found this on the web.  8 parts!! It's from an old PAIA stompbox design.

I can sort of understand how it works I think, we are robbing current from the Op amp's feedback path, which changes the cutoff frequency.....but I was curious how it sounded, so I perf'd it.

I tried different cap values--anything from .01 to about .2 is worth a listen. The NPN can be whatever I figure, I used a 3904.  I used a 741 for the opamp since that seems appropriate for the era.

The 1MB values must be to not suck too much current out of whatever is feeding this filter I am guessing.  I didn't mess with those values, but overall, parts values are not critical; from messing with this micro circuit the caps can be different values for instance and the VCF will still work.  I mocked it up in everycircuit and it appears to be a lowpass of some stripe.

So how does it sound?  Well, strange. With a triangle wave going in it sounds to me like some of the filters you hear in really old japanese drum machines.  It's worth taking 15 minutes and perfing I think.

I may incorporate it into a Lunetta VCO sound maker I am building and then post some samples somewhere.

Here is the schematic:


Here it is on perf:



More later....in the meantime Don't breathe the fumes!

Tuesday, July 3, 2018

Creating Custom GUI Elements in Reaktor 6

Putting down the soldering iron this week to focus on software that lets you DIY your own FX plug ins--Native Instruments Reaktor.

With Reaktor 6 you can whip up synths and what not, I feel Reaktor synths usually sound a bit thin, but for recording projects, Reaktor is VST duct tape, used to solve simple and maybe not simple problems.

Need to flip L and R channels in a WAV file?  Reaktor can do that (it's easy).  Need to make a stereo WAV into a mono file and control overall volume of the result?  Easy.  Need to rerecord a stereo file as mono, add EQ and a tape delay, then use the whole Mishpucha as a VST in Ableton, and then loop it?  You can do this with different software, but Reaktor makes it really easy.  Those are some damn clever guys at NI. Audio duct tape!  Yeh!!!!

For instance: I did a session the other day where the DJ dude wanted a drum roll that started at normal speed and slowed down in a controlled manner. There are probably 100 ways to do this, but to see if I could work fast, I created a simple reaktor wav player-recorder and tied a slider to it, so when you hit a start button, it started playing, and the slider adjusted playback speed that fed into a Recorder.  Save what's in the recorder to stereo WAV after the sample playback is finished and dump the modded WAV into ableton. We are done!

And of course after the session was over left I couldn't help tweak the duct tape ens file:
  • The playback/record starts when the Manual "speed" slider is put at the top of its travel.
  • A "Counter" that allows you to dial in the frequency at which the playback sample slows down if you don't want to do this manually.
  • A switch to allow the sample to start slow and speed up vs. start fast and slow down (oh wait, haven't added that yet?  Damn, you are never done with Reaktor....)
  • A custom UI for this thing.  Makes me look like a cool DSP dude working for Ohmboyz?  Not really, this is more script kiddee than math wiz but I can pretend?
That's the thing about software right?

OK, in case anyone is interested, here's how to create custom GUI elements in Reaktor.  It doesn't change your synth, It doesn't change your duct tape, but it changes the look and feel.

It will turn an ens., instrument etc. from this:



Into this:


(Why?)

( I have fun with messing w/ this....no other reason....)

OK What do you need to do this?
  • A graphics app that can produce PNG files where you have good control of what graphic element goes on what pixel in a controllable manner.  Adobe Illustrator is what I use but lots of programs can do this.
  • NI Reaktor, the $199 version, not the free player.  Comes with Komplete. You can't edit things with the player but you can play things made with the editor.
  • Optional: Knobman, a totally great free Java based app that allows you to easily create elements like knobs and sliders to use in your plugins--like the ones we make here.
  • Some time to mess around and have fun with this mindless Audio DIY distraction.

First figure out the size of the ensemble background, (you can guess and tweak) for my sample player/recorder/speed tweak ensemble it's 1000 x 300 pixels W x H.

Using Illustrator, I created a background PNG and gave it a kind of blue meany color.


And then added some basic elements.  Yes you have to know some Illustrator basics to do this, but it's not that hard a program to use to make basic shapes like rectangles and whatnot.  As I always say: if I can do this anyone can do this!



Illustrator has a native format on Windows: *.ai.  Assuming you're using that, save the .AI file, and then file > export as PNG.  Make sure PNG backgrounds are saved as transparent.  If you use a different program (Linux GIMP comes to mind) your process for this will be different....but at the end of the day, you want PNG graphics with transparent backgrounds--those work for me anyway.

Hint: as you go, do many "saves as", use github for version control, or whatever.  And: Always save versions of the graphics file in its native format (.ai or whatever) as well as the exports of PNG files. So you want "slider1.png, slider2.png etc. as you tweak things more and more.  I can't tell you how often I have to go back to previous versions for whatever reason!

OK with a working PNG file, let's add the background to the ensemble.
  • Open the ensemble and click on the EDIT button, then unlock the panel: 


So, go from this:


To this:


We now see a grid of dots in the background.

We need to change the background image:

Click on VIEW tab > STYLE > Bg Image:


And choose the PNG image you just created.  You use open from file...etc--this is self evident?



Once selected you should see the new background with the original buttons and sliders. Something like this:



Next it's a matter of modifying the background elements and replacing each slider etc. with whatever new artwork you want.  You can change some, all, or none.  As Bob Ross used to say--it's your wet on wet.  Wait did he say that?

To change out elements, select by clicking on the component in the Reaktor editor and then click on VIEW tab > Image.  Select a PNG file and see how it looks.

Let's examine that a bit more closely:

to make the elements not slide all over the place, go to your ens and add an image element. Now choose some sort of graphic you can pin to the corners. I usually put small Phillips screw images in each corner of the background image, or fully transparent 3 x 3 pixel PNG files.  You may or may not want to do this but here I did.  It defines the boundaries of the plug in and makes it so things don't move all over the place as you work.

After inserting these corner images into the ens, turning them on but turning off their labels; you are usually going to want to not use NI labels, rather text you create from your graphics program.



Once your "canvas" is set, you can tweak each image and its properties.   For each PNG file you can drop into your Ensemble or instrument or whatever Reaktor widget, below where you see the link to change the graphic, there is another link for "graphics properties".  Often the default values work, but one value that may need adjustment:  Reaktor will need to know how many frames a graphic element has.  A single item, like a Phillips screw, obviously has one element.  But for a button, a switch, a knob, anything that is treated a more like a cartoon, you will have more.  For a simple switch, there are two, one with the button on, one with it off, get it?


This is a 60x30 PNG, with each ellipse exactly 30 pixels total on the Y axis, and 60 on the X axis; they are shoved together perfectly without any space or slop.  A slider can have 127 or 128 images.   You are answering the question: how many frames does my "cartoon" have?

In fact, you'll quickly find that this sort of thinking is needed when working with Reaktor graphics:
  • Know your pixel count at all times (put the pixel count into the PNG filename if that helps?)
  • Don't be sloppy about X and Y pixel count as you create your graphic elements. It takes me more time to get things right when sloppy vs. when I'm careful.
  • Same idea again. Unneeded spaces, incorrectly cropped PNG source files, misalignments, asymmetries, etc., will make your graphic element almost always look crappy.  Work clean and work slowly.
  • Always save everything you use, and even what you don't use, as PNGs or another compatible file format (PNG always works for me).  You want to build up a library of switch PNGs and whatnot and use 'em over and over.
  • Be conscious of how many frames any graphic needs. 
  • Be ready to experiment.
As I say "be careful about your pixel count" what does this mean?  How do you know if you are creating an element that is 50H x 25W pixels, with text at 10 x 10?

Managing pixels, rulers and guides varies from graphics program to graphics program, but in Adobe illustrator for Windows 10 it's pretty easy: 

Edit > preferences > guides and grid
Choose 10 pixels with sub every 10 (works for me anyway):


Say OK

Then make sure grids are turned on and elements snap to them:  View > show grid and view > snap to grid.  That tends to make things line up.

One tricky thing: dealing with a 2 position switch. In the ENS here, that's the MANUAL/COUNT switch.  For this I created this 20wide x 100high PNG file.


Note the spacing, it's not spread out equally--the top and bottom images need to touch.  Got that by trial and error.....

And then set image properties like this:





The final thing to discuss is the sliders. I  created these with Knobman.  There are good tutorials on line for this software, as well as several really good knob files including knobs, buttons, VU's etc. you can download for not a penny, but one thing to reiterate yet again is that the number of frames in Reaktor always needs to match the number of graphics elements created in Knobman; otherwise the slider or knob image jumps all over and looks really bad.

I created a knobman 180 x 40 sized slider with 0-127 frames which must be mimic'd here.




OK that's it for now. It's off to the 4th of July celebrations but when that's done and I have a few of these I'll try to post a few reaktor things on my site.


Synth Gates, Interrupts, and Arduinos; a Million and One Uses

Yes once again: more Arduino Control Voltage Fu. Continuing from last time ...I am focusing on another corner of the Arduino for audio wor...