Tuesday, 9 February 2016

555 Flyback Driver and Plasma Speaker Part II

In the previous post I discussed designing a 555 based plasma speaker. I have etched and drilled the PCB and mostly populated it.

Here is the previous post in case people missed it - 555 Flyback Driver and Plasma Speaker Part I

I'm missing a couple of key components so I haven't been able to fully test the circuit. Here are some photos of the PCB being constructed:
The design transferred to the copper clad board
The etched PCB before removing the toner ink

The next part to be getting on with whilst waiting for parts is to design an enclosure for the high voltage part.  I don't want anyone to be able to touch the arc but I also want to try to cause the sound to resonate so it can be heard.  I'm basically going to design a speaker enclosure without a paper speaker cone.

I could design and print an enclosure using a 3D printer but I prefer to laser cut enclosures because it's quicker and I personally really like the wood finish.  Don't worry only the high voltage arc will not be exposed to the wood - that would be bad and would cause charring and fire!

I sketched up a quick idea on a piece of paper which purely shows the kind of thing I'm looking for.

Simple enclosure Idea for Plasma Speaker
From there I went to Inkscape and using the tabbed box maker extension I created a 72 x 72 x 72 mm square box.  My plan is mount the HV probes in the box with a mirrored acrylic behind the probes to maximise the arc from a purely aesthetic view point with a wooden case all made with on a laser cutter and glued together.  From Inkscape I exported the files in DXF format into solidworks so that I can render them in 3D and so that I can add holes and other features.  I prefer to work in solidworks when designing enclosures.

Here is what I came up with eventually.  I also designed some holders for the HV probes which I'm going to 3D print.  I'm hoping everything will work out ok!
Plasma Speaker Assembly - ISO view

Plasma Speaker Assembly Front View

HV Probe Holder

HV Probe Holder - Side View

HV Probe Holder - Top View
What I need to do now is get all of these parts laser cut and 3D printed and get on with assembly.

That's all for now - Langster