Daily-ish goings on at Marmot Audio HQ.


For years I've struggled making circular scale graphics to use in Front Panel Designer. The often-suggested way is to created the graphic in an external program and then import it into FPD as a .HPGL file. However, the only package that seems to be able to do that is Inkscape. Apparently you can do it by installing a 'virtual Post Script' printer and then tricking the likes of Illustrator to use it to print to a file. I had a go at that but, frankly, life is too short.

I've abandoned Inkscape of late and have migrated all of my panel designs over to Illustrator. I tried exporting a drawing in every single format that Illustrator can chuck out but none of them are liked by FPD so that is a dead end.

Instead I thought I'd see if I could coax FPD's somewhat limited feature set into doing the job. As it turns out, it's object rotate function has a couple of nifty feature that make it quite useful.

Create the graphic that will be used to make up your circular scale:

 

he object becomes your top-centre division on your scale. Select the object and choose "Selection -> Rotate":

 Here's where you need to pay attention. Set the Rotation Point Y offset (DY, highlighted in green) to the radius of your circular scale. In my example I've used "-10.00mm" which will eventually give us a circular scale based around a 20mm diameter circle. The value is negative to rotate the objects downwards.  You then need to set the angle of Rotation (coloured blue). You need to calculate this yourself based on the overall angle of rotation of the control/scale (for example, most Alpha potentiometers have a rotation angle of 300 degrees) and the number of divisions you want. I'm using -20.00 degrees here which will give 18 divisions (360 / 20). For some reason, negative rotation values make the object rotate clockwise which seems counterintuitive to me.  The important bit is the "Apply action to copy" setting. You need this on so that Inkscape will rotate a  copy  of the object rather than just rotating the original.

Here's where you need to pay attention. Set the Rotation Point Y offset (DY, highlighted in green) to the radius of your circular scale. In my example I've used "-10.00mm" which will eventually give us a circular scale based around a 20mm diameter circle. The value is negative to rotate the objects downwards.

You then need to set the angle of Rotation (coloured blue). You need to calculate this yourself based on the overall angle of rotation of the control/scale (for example, most Alpha potentiometers have a rotation angle of 300 degrees) and the number of divisions you want. I'm using -20.00 degrees here which will give 18 divisions (360 / 20). For some reason, negative rotation values make the object rotate clockwise which seems counterintuitive to me.

The important bit is the "Apply action to copy" setting. You need this on so that Inkscape will rotate a copy of the object rather than just rotating the original.

ou should end up with something like this:

Here's the handy part! With the cloned object still selected, choose "Edit -> Repeat Rotate"

And Inkscape will repeat the rotation you just setup. Do this as many times as you like/need until you end up with something like this:

 Note: it's even quicker if you remember the Repeat Rotation shortcut key, in OSX it's CMD+R

Note: it's even quicker if you remember the Repeat Rotation shortcut key, in OSX it's CMD+R

So, that gives us one half of the scale. To make the other half, select the original object again at the top. Choose "Selection -> Rotate" again but this time set the Rotation angle to a positive value, here in my example it's 20 degrees (highlighted in red). Don't forget to set the DY value (green) and make sure "Apply action to copy" is still selected.

Use the "Edit -> Repeat Roate" command again to populate the other half of the scale and you'll end up with this:

ou can then group them all together (drag-select, SHIFT+G) and then drag the group to line up with your drill hole:

Lovely!

In my example I used a circle so it's not obvious that as well as rotating the position, the object itself is rotate to orientate correctly to the circle. This works with any kind of object, even text (though you have to do each letter individually!)





| FPD Front Panel Designer scale circle circular array DIY panel modular

Published on by Neil Baldwin.

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Been working on this for quite a while and am so happy to have got it into a state where it's actually presentable.

It's a Sonic Potions LXR drum machine in a custom acrylic case that is opaque with cut-outs and coloured acrylic inserts for the different coloured indicators - all the LEDs are actually white. The LCD is also covered with a clear panel (actually fluorescent blue!). The current to the LEDs is still not right and needs reducing but you get the idea. I was really keen to find a solution that would break the need for a transparent (or semi-transparent) case.

I'm also in two minds about painting in the engraving. The top panel is made from a special acrylic that is metallic grey but when engraved should show through black but I couldn't get my laser cutter to cut it deep enough.

I've also made a top panel from frosted white acrylic (again with coloured inserts for the indicators) which gives a very different look. I'll post pictures of that one assembled once I've sorted the current-limiting on the LEDs as you get a lot of light bleed through the semi-transparent material.

Transient
Transient
Transient
Transient





| Sonic Potions LXR acrylic custom case perspex custom case

Published on by Neil Baldwin.

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While most of you were enjoying the sunshine, I was busy packing up the latest batch of Elektron stands!

9 news sets, winging their way to customers in London, Birmingham, Sheffield, Belgium, Sweden and Chicago!




| Elektron End cheeks stands acrylic Monomachine Analog 4 Machinedrum Octatrack AR Analog Rytm

Published on by Neil Baldwin.

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Forgot to post this: I modded a client's Metasonix D1000 drum machine recently to bring the filter resonance controls to a more accessible place on the front of the case (they're normally hidden away as trimmers on the PCB) This means you can manually modify the filter feedback to give the valve percussion monster some new skills on the drone front. He was so happy that he made me a demo of the results. So good!





| metasonix d1000 drum machine valve mod resonance

Published on by Neil Baldwin.

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Sometime last year, at the request of a client, I made this curious little box. The connectors on the top row can be connected to their corresponding lower sockets by putting something conductive in the slot in the middle and then setting the corresponding switches to either permanently on/off or pushing down for a momentary connection. It was built for my good friend Phil Julian/cheapmachines as a performance device.

 Johnny 5!

Johnny 5!

Because it essentially 'short circuits' the top and bottom rows of connectors I nicknamed it "Johnny 5". And of course, who doesn't love that 80s robot-based buddy film / love story with it's charming racial stereotypes and it's feel-good theme song courtesy of El Debarge (that bassline!)

Anyway, Phil contacted me last week to ask if it would be possible to change Johnny 5 from mini-jack connectors to banana sockets!

But wait! No disassemble Johnny 5!

 Nooooooooooo!

Nooooooooooo!

Ignoring pleas for clemency I set to work hacking out those mini-jacks (which due to the common ground bus I'd painstakingly built....Phil), drilling out the holes and installing the banana sockets, Jonny Five is reassembled and winging his way back to the big city.

Reassemble, Ste-pha-nee!

I'm sure he looks a little happier with his red eye makeup!

And just because, here's that famous scene....




| diy performance modular short circuit disassemble johnny five

Published on by Neil Baldwin.

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