Tuesday, July 17, 2018

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

Several years into the DIY thing and I still trying to figure out how to make low-cost, low quantity, high quality front panel silk screen art.

Still can't solve that one!

Update! I am using Front Panel Express as well for this--see the post here, it's about $40-50 USD for a single 1-U Frac, that's not what I call low cost, but they make great stuff....

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

That's what this post is about.

No, I don't work for these guys. This isn't an ad or promotion. This is however the best way to make low cost one-off front panels that I have found to date. it's $1-$2-$3 USD per panel, pretty affordable.

Still with me?

Next, go out and get this stuff: "Lazertran." You can find it online direct from the manufacturer, 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. As of 12-16-19, with tax and shipping it's about $3USD per sheet.

There is one Lazertran version for laser printer and another for inkjet. Before you Begin! Make sure you have the right printer. There is a list of printers that work on the Lazertran website in the faq section, go here. Hewlett Packard B+W printers (which is what I have) supposedly all work; mine does. I have also read (here) that older Lasers work better than newer ones.

I set my HP 402DW to "heavy paper 130g" so you set up the printer to use card stock; your printer might be different. Lazertran is a bit on the thick side so set your printer accordingly.

I only have tried the process here 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: the required safety stuff. Please be safe! This process involves putting paper and metal into an oven and cooking it for a few hours. You have to be sensible or you wouldn't survive a week of DIY.....So please, don't be a bozo about this--be careful while handling hot materials, you could burn yourself.

In addition to staying safe, 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 250+ F 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.
  • Paper towel for smoothing out tiny bubbles
  • 800 to 2000+ grit wet/dry sandpaper.
One more thing: all the temperatures in this post use the Fahrenheit standard. I know it's downright colonial for me to do that, many of you use Celsius, and most of the time I try not to be a stupid American who thinks the world only exists from Hawaii to New York. I didn't want to constantly post 2 numbers. If needed Here is a good site to translate between the 2 standards.

OK let's go:

Prepare your metal work. For Lazertran decals to look decent, your front panel has to be extremely smooth--the decal will tear and hang up on any burrs or rough edges, form bubbles over oil and dirt, and generally look crappy. I thoroughly wash the panel with dish soap, then sand it with 800 grit wet and dry sandpaper, then a 1200 grit sanding pad then wash it again.

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 $2-3USD 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 or PNG and then use that as the background in Illustrator or whatever graphics program you use.

Eagle BRD file of a Fracrack 2u panel

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 inkjets can't print white and I don't see that Lazertran is supported for most or all color laser printers. B&W printers assume the background is white and treat white artwork as clear so it can "show through".

I imagine from model making that CMYK colors may appear a bit faded or washed out so flat white paint on the panel before decaling may help. 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.

OK, 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 Lazertran docs say to use a hair dryer, but I use my oven as I've had better results. For this pre-bake-your-decal-sheet process, preheat your oven to 225 degrees F. and then put in the decal for about 6 minutes.  

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

Update: I have gone back to using a heat gun for this. Specifically I am using my hot rework station to bake the decal vs. the using the oven; 3 minutes of blowing the rework nozzle at the decal at 475 degrees seems to do the trick. Probably not what Sparkfun thought of when they put the HAR device on the market?

Charred Lazertran.  Mmm Mmm stinky!

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 over bake the sheet....then the decal won't come off, so keep checking on your decal during this pre-bake. I have best results when the backing paper is charred to about the point you see in the photo above.

Next, cut out the decal along the panel lines:

if you can, cut out each drill a bit larger than needed (say 100-200 mils)--you will get less bubbles if you lay decals down on flat continuous metalwork vs. having them covering up drills.

Then soak each decal in warm tap water for about a minute--less if you can. Warning: Soak for as short a time as you can; if you soak the decal too long the decal 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. 

UPDATE: I finally figured out what the issue is with disintegration! 

Since about mid 2019 Lazertran put a protective opaque coating over the "decal side" of their decal paper. You need to peel off before running it through your printer.  I was having about 30% failure rates with disintegration and I couldn't figure out why. 

After looking at the failed sheets under a microscope I discovered removing the opaque protective sheet was also removing the decal material itself. The two look alike so it's hard to tell! So: Be super careful when removing this protective sheet. 

The decal material has a slightly matte/bumpy look when you first peel of the protective layer, but becomes shiny after the "heat the decal" process described above. If the decal doesn't get shiny when you heat it up you probably removed the plastic decal material by mistake; and your decal will be butt and disintegrate. Face!.

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,  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.   


Preheat a cookie sheet to about 225  degrees and before the initial bake, remove the sheet and put it on your counter.  Then, put the metal panel w/ decal face up directly on the sheet. I have seen some bubbles I missed immediately bubble up at this point. They can be pushed back down with a quick stab with your fingers. Yes, a 225 degree metal cookie pan is hot , so be careful, but this "prebake, prebubble" step is completely essential.


With the decal now fully debubbled, set you oven to 170 F and put the decal in there for 2 minutes.  

Important: After 2 minutes remove your cookie sheet, 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, thus repeating what you did in the "Prebake."

After about 10-15 minutes the big ones are with you to stay.....so set your timer and do this check.

(I have done Lazertran bakes in a pan, on tinfoil and on a cookie sheet--after trying different things, baking on cookie sheet seems to work best....)

After the two minute check, try another check at 10 minutes; after that you're past the bubble popping stage. 

Keep the oven at 170 F 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 190 F for an hour, then 220 F for an hour. OK, 250 F for an hour, finally 275 F for an hour.  

Don't go over 275--the decal might burn if you do.  Not 100% sure about this--I have gone to 350 F without issues, but other times going above 275 will make the decal turn brown.

When all this is done, remove the cookie sheet from the oven, and let it cool.  Next remove the panel from the sheet with your tongs. After your 4+ hour bake, if everything went OK, you end up with a pretty darn good looking panel, not quite pro silk screen looking, maybe a few blemishes here and there, but close.....with some practice you can get really close.  

Look Ma! No Photoshopping!....if you are careful with lazertran the results can be very clean.

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!

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 off. 

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

I have experimented with clear coating, but am not sure that improves things any.

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 Lazertran. 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. 


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 change those values, overall, part values are not critical for this circuit; from messing with this micro circuit the caps can be different values for instance and the VCF will still work. 

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 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:


( 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.

ProMicro HID Keyboard Emulator

Quick one this time. The Arduino ProMicro (examples here and here ) is based on an Atmel 16u4 MCU and has HID keyboard emulation ready to go...