Simple Guitar Pedal Front Panel Drilling Guide Moderators: adafruit_support_bill, adafruit

[HarpDude]

The lead guitar in our classic rock band dropped out suddenly during a live performance. We struggled to quickly find the problem. The guitar solo for Comfortably Numb was coming up soon. The guitar player eventually found a bad cable in the guitar's pedal board chain, fixed it, and went on. It simply took too long to find the problem -- the pressure of a live performance, ya know -- so I designed a guitar signal troubleshooter that can be placed anywhere along the chain of guitar pedals and moved around as needed to locate lost signals. The troubleshooter is a no-load visible sniffer that provides a simple view of the guitar-level signal including peak and average levels. Great for troubleshooting between pedals in the chain. The design includes a swappable input buffer amplifier that attaches to the main internal PCB. This is the analog version; the Feather version is mostly designed and is next on the studio project list.

The reason for this post is to share a simple trick for accurately drilling holes in project front panels. Since the internal circuit for the troubleshooter pedal used a PCB of my design, I included a front panel drilling guide next to the main PC board in the design file that was sent to the board manufacturer. It was very easy to duplicate the alignment and spacing of the LED positions to match the main PC board for the guide -- just a quick cut and paste of the LED positions in the PCB design software tool.

The result was a very accurate strip of holes, sized perfectly for the pilot drill. After aligning the guide to the pedal case, hand drilling was a chinch (and I don't have a drill press). I was pleasantly surprised to find that the guide was no worse for wear after the first use and will be able to be used a few more times without impacting the accuracy of the holes. Happy camper.

If designing a PCB for your project, look for ways to incorporate panel drilling/alignment guides. They are easy to lay out in the PCB design tool and help to make the final project look more professional.

The guitar pedal troubleshooter's front panel drilling guide (center) was printed as a PCB along with the main internal board (right).

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[adafruit_support_mike]

That's a great idea! Thanks for posting.

[HarpDude]

Since the PCB vendor (ExpressPCB) has a lower-cost standard size (3.8 in X 2.5 in), most of my designs use as much board real estate as possible, incorporating guides and other bits needed for other projects.

Here's the guitar pedal design image and the resultant PCB. The bits on the right are a chassis breakout and test jumper for another project.

Guitar pedal main PCB design rendered in the vendor's design tool.

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The final product just before separating the individual boards.

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