Hello,
I am currently working on a theremin project. This one exactly:
<LINK_TEXT text="
http://interface.khm.de/index.php/lab/ … ng-device/">
http://interface.khm.de/index.php/lab/interfaces-advanced/theremin-as-a-capacitive-sensing-device/</LINK_TEXT>
There is a schematic and breadbaord diagram if you scrolld down. The author has also mentioned this: “Care must be taken in the choice of the parts L1 and C1. C1 must be a ceramic capacitor NP0 type (zero temperature coefficient) and L1 a high Q inductor suitable for high frequency such as a Neosid 00612299 but for the first test a standard 10uH Choke will do also the job.”
I ordered this item:
http://www.mouser.com/ProductDetail/Kem … NqjGH0g%3d
Datasheet:
http://www.mouser.com/ds/2/212/KEM_LF00 … 417258.pdf
So my first question is this, will this inductor be applicable for this circuit. Can it work. The datasheet doesn’t help me much.
My second question is, how the heck do i put this on a breadboard. It has 4 pins and im not completely sure how it works. Any help will be appreciated.
Urs Gaudenz out of Germany I consider #1 in the world for theremin building using an Arduino.UNO You might want to keep an eye on his website. [Open Source Uno Theremin
I am unable to help much with your approach as I myself am more old school analog interested in developing the classic opera sound. The classic theremin does something unique which cannot be done with a keyboard. If you want to make triggered sounds most likely the keyboard will be easier.
At the high frequency your design operates most likely “will not” work assembled on a experimental proto type plug in board. The oscillator sections need to be hard wired on a generic pcb. A coil called a choke is still a coil and will work if the uh value is correct.
Speaking of theremin opera Be Amazed using a “Talking Box” digital add-on for a [remarkable sound.
Theremin building is addictive and dangerous as I began with long black hair some time ago and now look like the white haired professor from “Back to the Future”. So be careful. :o
Christopher…damit I need a nap!](https://www.youtube.com/watch?v=a2cQ7NYM_Wc)](OpenTheremin V4)
4 MHz isn’t exactly “high frequency”, so building something on a breadboard should work OK. However, building it “dead bug” style on an unetched PCB will give better results.
An air wound coil will give best Q, winding on a powdered iron or ferrite toroid would be second best (and most convenient), and a small molded inductor would be my third choice.
Also, the part you ordered is not a simple inductor, which is a 2 port device. It’s designed to be used as two inductors sharing a common core, used in EMI/RFI suppression on something like an AC power cord.
Ah, I see. So would this work: http://www.mouser.com/Search/ProductDet … 7-2150-24K
If not, could you link me to a high q inductor that i can use on mouser.
I like your choice of coil or similar [this might be better.
A common expression in theremin building is you must pass through 10,000 reasons why it won’t work effectively before you have success. The theremin approaches the metaphysical realm and will kick the ass of non believers. :roll:
You want to keep all the oscillator wires as short as possible on a generic PCB. The plug in experimenter boards have too much inner electrode capacitance for effective oscillator operation.
The hand sensitivity of a theremin effect is in the femto farad range which is less than 1 picofarad. The experimenter boards have 3 to 5 pf between rows which is a lot in this application.
Good Luck you are going to need some.
Christopher](http://www.mouser.com/ProductDetail/API-Delevan/1025-44KTR/?qs=sGAEpiMZZMsg%252by3WlYCkU90U%2F30FuCqI4hw2ab82Mxg%3D)
So how important is Q to the circuit? Values for the two datasheets linked above are under 60.
Page 15 of this Micrometals document shows 45 turns of #26 wire on a T50-2 toroid to have a Q over 200 and inductance around 11 uH.
I haven’t checked to see if Mouser carries Micrometals products, I know they carry Fair Rite.
http://www.micrometals.com/downloads/Q% … ue%20H.pdf
Dave