Building a surface-mount EW Theremin

Posted: 3/5/2014 10:40:35 PM
arpuffer

Joined: 3/5/2014

Hey, folks

Years ago I wanted to get myself a Theremin, but they were too expensive.  Presently I find myself in my 5th year as an Electrical Engineering student.  I've done some designs, laid out PCBs, and it just occurred to me that I can just build my own instrument at this point.

Here's the kicker:  I want as many components to be surface mount as is possible.  I've got the tools for assembly, the only questions are for getting the Bill of Materials together, specifically inductors.

I'm keeping the TOKO coils in my design, but I'm trying to figure out what is acceptable inductor-wise for the rest of them.  I'm not particularly well-versed in inductors, but it seems like some of you guys are very experienced--hopefully the community has some ideas there!

Posted: 3/5/2014 11:45:37 PM
Chobbs

From: Brooklyn,NY

Joined: 12/1/2009

Others may have more input, but id recon that you will definitely have to go thru-hole for the antenna inductors.

Posted: 3/6/2014 12:12:39 AM
arpuffer

Joined: 3/5/2014

http://octopart.com/sdr0503-103jl-bourns-96010

This is one of the surface mount options.  Same inductance, same tolerance, much lower Q value (though I'm not sure how much Q matters here).  Max current is also lower, but I'm not sure if it's at the point of being too low.



I'm totally cool with going through-hole as needed, but looking for surface mount wherever possible.  Until I get some feedback on the surface parts, the through-holes stay on my bill of materials.

Posted: 3/6/2014 12:38:23 AM
RS Theremin

From: 60 mi. N of San Diego CA

Joined: 2/15/2005

arpuffer,

If cost was an issue early on you can purchase a new EWS board for $96.

Successful theremin building is not as easy as it appears at first. Every component is selected and positioned with purpose. It is an excellent way to test your understanding of the electronics and what you have learned.

The theremin will kick your ass at first seeming to test your persistence and the designers worthiness. (-'

Good Luck on your journey

Christopher

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