See-through shielding for showing off interior artwork?

[EBK]

I have an unusual question regarding what is really more art project than pedal design, but here goes....

When I get my workshop set back up in a month or so, I'd like to build a pedal or two in a visual style somewhat similar to that of Peter Vogel (search Google for "peter vogel sound sculptures" to get an idea). 

I would like the pedals to be fully functional, and that means a shielded enclosure is a must.  Ideally, I would light up the inside of the enclosure and have some sort of window through which the "artwork" could be seen. 

Could I reasonably get away with a normal grounded Hammond enclosure with a sizeable hole cut out of the top?  Would I be better off with some sort of metal mesh, and if so, how coarse of a mesh spacing could I use?  Are there other solutions that would provide adequate shielding with good visibility?

Any suggestions would be appreciated.  Thanks for your indulgence.

[vigilante397]

There is a company called Snakes Pedals that uses hammond boxes upside-down and replaces the bottom plate (now top plate) with plexiglass so you can see inside. This would probably be one of the easiest ways to do it. Though their intentions in transparnecy are a little different, as you can see here:

[EBK]

Found this sheet of Indium Tin Oxide coated PET:
https://www.adafruit.com/products/1309

Maybe it could work.  (Maybe it's overkill.)

[vigilante397]

If you're thinking of just cutting a little window in the top something like that could work, but if you're planning on replacing a whole side with it and mounting a switch/other hardware on it you're going to want something a lot thicker.

[EBK]

If you're thinking of just cutting a little window in the top something like that could work, but if you're planning on replacing a whole side with it and mounting a switch/other hardware on it you're going to want something a lot thicker.

Yeah, I definitely understand.
My initial thought was to make a large window using cast acrylic sheet and retain enough metal to securely mount the stomp switch and other controls.
If I used something like the conductive film it would be placed behind the acrylic and taped to the enclosure using copper shielding tape.

[vigilante397]

Yeah, I definitely understand.
My initial thought was to make a large window using cast acrylic sheet and retain enough metal to securely mount the stomp switch and other controls.
If I used something like the conductive film it would be placed behind the acrylic and taped to the enclosure using copper shielding tape.

Ah, I see what you mean. In that case I think it's a bit of overkill with the conductive film. There is enough metal already to form a perfectly reasonable ground for the vast majority of circuits. I very seriously doubt you would notice a difference with or without the film.

[EBK]

That is what my suspicion was as well.  That is why I initially phrased my question as "how big of an unshielded hole can I get away with?"
I can always try it and see.  Should be easy enough to experiment with an enclosure and a piece of foil for a lid.

I still have my Engineering Electromagnetics textbook on my shelf.  Maybe I should crack it open for a refresher.

[kaycee]

I've built several with clear acrylic windows and had no problems. A Fuzz Factory and a Repeat Percussion, both on tagboard have been fine. I cut viewing holes in Hammond boxes and super glued the windows inside.

[vigilante397]

I thought I remembered seeing something like that before. Dug through and found yours, really excellent looking build

[samhay]

>"how big of an unshielded hole can I get away with?"

It likely depends on the type of circuit. If it is not super high gain, the answer is probably as big as you want.
As a sanity check, build the circuit and 'rock it before you box it'. If the noise is not objectionable without any shielding, then some shielding is probably not going to make it any worse.

[davent]

Leevibe's stunning Class of '77 . Circuit was cast in resin then installed in enclosure cutout. This pic just scratches the surface.

Details here. http://www.madbeanpedals.com/forum/index.php?topic=19000.msg183942#msg183942



dave

[EBK]

Leevibe's stunning Class of '77 . Circuit was cast in resin then installed in enclosure cutout. This pic just scratches the surface.

Details here. http://www.madbeanpedals.com/forum/index.php?topic=19000.msg183942#msg183942



dave

So beautiful.

[bool]

Thats a top-notch league build.

[digi2t]

Speaking of "see-through sheilding", how about some see-through sheilded cable for the input/ouput leads?



Or better yet...



If you're gonna show off... then show off!  Right!?

[duck_arse]

.... "gut shot", or it didn't happen. I don't see any guts .....

you could always build a dummy. look-a-like or look-a-totally-unlike pcb, mount the real one inside all shielded, and then put the dummy with window over the top (so to speak). 'have your guts and neat it too.'

[EBK]

.... "gut shot", or it didn't happen. I don't see any guts .....

you could always build a dummy. look-a-like or look-a-totally-unlike pcb, mount the real one inside all shielded, and then put the dummy with window over the top (so to speak). 'have your guts and neat it too.'

That sort of gave me an idea for another pedal: A window appearing to show every wire from every switch, pot, and jack connecting to a single LED (no board and no other parts), which lights up when the effect is activated.  The real circuit board would be hidden from view.  I may have to build that one first!

Or, a variation on that theme: A window showing a bunch of loose parts unconnected to anything, just free to rattle around.

[MrStab]

for a second i thought there was some Los Pollos Hermanos situation going on, but with ghanja and pedal companies

[midwayfair]

See-through .... SHIELDING?!

[kaycee]

I thought I remembered seeing something like that before. Dug through and found yours, really excellent looking build

Thanks for the nice words  Leevibe's is in a whole 'nuther league though, beautiful.

Here's the others, Buzztone and Repeater. The Fuzz Fac has two colour change LEDs with trims to make them splutter as they change, lighting up inside.

[amptramp]

There are a lot of manufacturers of shielded windows:

https://www.chomerics.com/products/display/index.html

Chomerics was the go-to company for most of my career in avionics.

Another choice would be wire mesh screening.  Gives anything an old-school (piston engine era) avionics look but is also compatible with a steampunk look:

https://www.twpinc.com/wire-mesh-material/copper/rfi-shielding-mesh

You can test the circuit in the box with the window hole cut but no window in it, but you can never be sure you are getting the worst-case interference if you are testing at home.  Run an electric drill, spiral fluorescent light and a computer beside it to make sure you are not just in a quiet ambient.