Synth Project: Creating Front Panel Layout and Wiring Plan

Knob

For the Synth-DIY Experimenter Board project I needed to create my own panel layout and wiring plan.

I chose to do this with a 2D vector drawing package called Inkscape. This was my first time using Inkscape and it performed well except for some minor deficiencies.

You can find all the files I created with Inkscape in the Saund-Box-Files repo up on GitHub.

Inkscape Setup

For this project I’m trying to fit the panel on to a legal size page (14″ x 8.5″) so I created a new Inkscape file with a legal page size in portrait orientation and using inches as the units:

Screen Shot 2014-11-30 at 11.06.18 PM

And setting a rectangular grid of 1/16″ with major lines every 1/8″:

Screen Shot 2014-11-30 at 11.05.55 PM

Would have liked to set the grid to every 1/32″ interval but Inkscape only allows values up to 4 decimal places to be entered:

Screen Shot 2014-12-01 at 12.49.17 AM

With this setup I could work explicitly in inches and know that everything is to scale.

Finally, divided the file up into the following 7 layers:

Screen Shot 2014-11-30 at 11.01.07 PM

Templates Layer

In the Templates layer I created and managed all the graphical elements needed for the panel. This broken down into three main areas: Panel artwork, components and front panel trim:

Screen Shot 2014-11-30 at 10.59.19 PM

One of the big issues I had with Inkscape was its inability to specifying an anchor point for each graphical object. This was a problem for non symmetric objects like the dial markings and the potentiometer components as their bounded center points do not match with their placement center points (i.e. the crosshairs).

Did manage to work around this problem by adding “invisible” boundary lines that have their opacity to 0%:

Screen Shot 2014-11-30 at 11.19.39 PM

Hacky but it worked.

Tip: When placing objects use the “clone” feature (i,e, Alt-D) rather than copy and paste:

Screen Shot 2014-12-01 at 8.08.45 AM

This way if you decide to edit or modify an element then all its clones will update automatically.

Boundary Layers

Before doing any work I first created bounding regions for the art (the blue box) and the components (the red box). This helps ensure that there is enough space around the edge of the panel for mounting on to an enclosure. As I was trying to pack in as much as I could on to the panel I had the mounting area be only 3/8″. Hopefully that is enough.

Screen Shot 2014-12-01 at 1.06.48 AM

Art, Trim and Component Layers

With the template and bounding regions done it was just a matter of laying out the panel. Due to cramped space it ended up being quite a puzzle. Still after a few iterations I did managed to settle on a layout that worked well:

Screen Shot 2014-12-01 at 1.07.45 AM

For most of the art and design I duplicated what Ray Wilson did for his build of the Experimenter Board.

Availed of the alignment tool extensively to manage placement of elements as the lack of custom anchor points for object meant the grid was not as effective:

Screen Shot 2014-11-30 at 11.07.18 PM

Used the Components layer to ensure components fit inside the enclosure space behind the panel and with each other:

Screen Shot 2014-12-01 at 1.09.35 AM

Used the Trim layer to ensure artwork was not placed too close to mounted components such as switches and banana jacks:

Screen Shot 2014-12-01 at 1.07.57 AM

Also used it to color code the banana jacks. Yellow for output and blue for input.

Coloring Layer

Used the Coloring layer to help with choosing colors for the knobs and LEDs.

Screen Shot 2014-12-01 at 1.09.06 AM

Settled on: Yellow for adjusting output levels; blue for adjusting input levels; red mainly for frequencies and rate settings; green for all other module parameter adjustments.

Creating the Wiring Plan

Once the layout was finalized I created a new wiring plan document from the layout document and did the following steps.

Reorganized the Layers

In the new document I selected and deleted all of the layers except for Art, Components and Component Boundary. Note that deleting the layers themselves does not delete the layers’ contents. You need to explicitly select and delete all content in each layer first, otherwise they get assigned to another layer.

Then added two new layers, Signal Wiring and Power Wiring, renamed Art to Front and ordered all the layers thus:

Screen Shot 2014-12-01 at 10.15.11 AM

Flipped the Layers, Labeled Components

Next I horizontally flipped all the objects in all layers to create a “from the rear” view of the panel.

Note: To do the flip correctly in Inkscape you need to use the select tool to drag a box around all the objects in all the layers, i.e. make all layers visible. The Select All (Ctrl-A) command only works for the currently active layer bit it’s important to select all the objects in all the layers to do the flip properly.

Once flipped I set the Front layer to 10% opacity which helps to provide some orientation for the components without cluttering the drawing. I then labeled each component, in the Components layer, with its designation and value (if it is had one):

Component Layer

Did the Signal Wiring Plan

In the Signal layer I added legends for all the wires going from the panel to the PC board, along with a short piece of wiring graphic so I can specify what color wiring to use for each. I also drew in any on-panel wiring for the signals. Initially I’ve made all the wires blue but at a later date will color code with actual wire colors being use so as to make it easier to wire it all up and debug. Also added, for this layer, legends for the power wires, i.e. GND, +12V and -12V:

Signal Layer

Created the Power Wiring Plan

Once the main signal wiring diagram was complete I used the Power Wiring layer to figure out the best routing for the GND, +12V and -12V lines.

Power Layer

Again, used matching wire colors to minimize errors and help with trouble shooting.

And that was pretty much it.

Conclusions

Inkscape is not a bad package. I particularly like how the line tool works when doing the wire routing. However, if I was going to be doing a lot of panel design I would definitely look for something more suitable. A package that lets you programmatically do the layout would be most ideal as, for the most part, a lot of the spacing between elements needs to be consistent. In fact, using something a kin to how HTML and CSS works would be perfect.

I’m amazed how enjoyable it was doing the panel layout and wiring parts. I like doing jigsaw puzzles so go figure. It also helped me better understand the synth modules – surprisingly – and I’ve now become over all much more confident about executing the project successfully.

Another benefit was being able to generate a texture of the panel for SketchUp. This made it a breeze to replicate the panel in 3D so I could better design the synth’s enclosure, particularly with regards to figuring out the depth of the panel once the PC boards are mounted. I’m finding SketchUp to be an invaluable tool for the DIY’er.

Here are some renderings of how this is all going to turn out:

SB Cabinet Front

SB Cabinet Back

One other interesting aspect about this whole process is having to commit to a final design. Been tempted to add one or two more modules, like an echo module and a simple sequencer, or mod the current module somewhat (like adding a sin wave to the oscillator). Of course being limited to 8.5″ x 14″ rules out any such additions to the current panel but I was toying with the idea of adding a second panel. Can see how this hobby gets out of control pretty quickly… and I’ve only built the power supply so far. Sheesh!

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5 comments

  1. roberto feliz · · Reply

    hi man… awesome work… i am wondering if you can share the template of the panel’s components… i am tryinh to build some panel of mine but i can not imagine that….. thanks.

    1. You can access all the files I created for this project on GitHub: https://github.com/solderspot/Saund-Box-Files

  2. Hello,

    I liked you work a lot.
    I was trying to load this in Inkscape, but had no success.

    My Inkscape version is 0.91.

    Which version have you used?

    Thanks, Alberto

    1. I was using v0.48.5 r10040. I’ll look into updating the files when I get a chance.

    2. I installed the latest Inkscape version (v0.91 r13725) and it was able to load the files with no problems.

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