Birth of the Smoke-O-Tron Enclosure

Before… Before shot.

After… Smoke-O-Tron, powered up!

My friend Dan built the electronics for a temperature controller for his electric smoker.  I figured since I have the CNC mill, it was a moral imperative for me to do some nice enclosure work for him to make the project look slick.  Dan admitted his initial attempts at the case work with a Dremel tool were lacking somewhat, so about a month back he passed the guts over to me so I could have a go at it.  It took a few attempts to come up with a design I was satisfied with and execute it well enough to consider it done, but I chalk all of that up to gaining experience on the machine.   I was pleased to finally be able to present the finished product to him last night!

The electronics originally fit into a waterproof PVC Carlon box.  The lid had been previously attacked with a Dremel, but I figured if I cut out a large window and made an insert for it, we could salvage it as well as end up with a nifty look.  So, I started out by CNC milling out a roughly 4.7″ square from the lid.  I then made a clear polycarbonate insert, just slightly smaller by about 0.010″, so it would slip fit inside and stay in place with a flange.  The polycarbonate insert received some decorative milling on the front panel, and some functional drilling on the rear panel to provide mounting and a place for the knob to pass through.  The insert also got an engraving treatment with some text using the new high speed spindle mount that I built last week.  Since getting engraving working well, I had tried a few experiments of back painting engraved text.  I did the same for the Smoke-O-Tron, using some water-based Rust-Oleum hobby paint.  I made sure the see-through LCD window was well masked off with the original paper that came with the polycarbonate as well as some supplemental electrical tape.  I sanded the back of the insert, avoiding the LCD window, with 220 grit in my random orbit sander, and applied a couple of coats of black spray paint.

The main electronics consists of the main PCB and a small character LCD.  After one misguided attempt of doing blind tapped holes in the clear insert (ugly and visible), I came up with the much cleaner “mezzanine” approach.  This is often done in front panel work in devices, especially when varying heights have to be accounted for.  The particular scheme I chose a completely clean front panel look with no visible screws.  The electronics mount to both sides of a small polycarbonate plate, and the plate itself is mounted to the PVC enclosure by way of some custom-length standoffs.  The standoffs also serve to sandwich the front panel PVC insert in place.

I also made a quick shaft adapter/extender for the encoder wheel, which adapts from 6mm to .250″ and provides a long enough shaft extension that passes through the mezzanine, front panel insert, and into the knob.

All in all, I’m fairly pleased with the end product.  It looks slick, and I have learned a few new techniques for future projects.  As usual, here is a video which details the making of the enclosure, and a bunch of pictures as well.

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