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Topic: arduino theremin parts required and help (Read 783 times) previous topic - next topic

abhishekk

I am a newbie to arduino,though I had worked on few simple projects like 4x4x4 LED cube,LCD display etc. so I am well aware about arduino and how to use it.
Straight to the point,I had gone through an article about making an arduino theremin here : http://interface.khm.de/index.php/lab/experiments/theremin-as-a-capacitive-sensing-device/
There,the author had posted the working and all...
I want to know what exactly the parts are required,can someone post a list of what and howmuch the components are required,as the schematic diagram does not strike me.
His schematic is quite complicated,if someone could design another schematic using fritzing or https://www.circuitlab.com/ or anyother service and post it here,it would be great help.
He has explained all about how it works,but actually I still do not get it how could just a 5mm wire sense how near a hand is and...


MarkT

The crucial components are the inductor and its capacitor, marked "NP0" - which is a grade of ceramic
capacitor that is temperature stable (unlike most ceramic decoupling caps for instance).  The inductor should be
high-Q and probably an iron-dust cored inductor would be best - something designed for LC circuits in
RF design, not for a SMPS...  It also needs to have a self-resonant frequency well above 4MHz - 100MHz or so
would be fine.

The other components won't be critical compared the the LC - the principle of operation is that the "antenna"
acts as a variable capacitor in parallel with the fixed capacitor and thus hand position will vary the total
capacitance in the LC circuit, shifting its resonant frequency.  Some experimentation may be needed with the
feedback components in practice
[ I won't respond to messages, use the forum please ]

abhishekk


The other components won't be critical compared the the LC - the principle of operation is that the "antenna"
acts as a variable capacitor in parallel with the fixed capacitor and thus hand position will vary the total
capacitance in the LC circuit, shifting its resonant frequency. 


Very well,thanks, now I understand it.

But,could you post a list of components what are required exactly?

MarkT



The other components won't be critical compared the the LC - the principle of operation is that the "antenna"
acts as a variable capacitor in parallel with the fixed capacitor and thus hand position will vary the total
capacitance in the LC circuit, shifting its resonant frequency.


Very well,thanks, now I understand it.

But,could you post a list of components what are required exactly?


I could, but I'm sure you can do that too  ;)  [ you will need to identify a good component supplier though - I'd suggest Farnell or associates, but it varies by territory ]
[ I won't respond to messages, use the forum please ]

abhishekk



I could, but I'm sure you can do that too  ;)  [ you will need to identify a good component supplier though - I'd suggest Farnell or associates, but it varies by territory ]


What do you mean by "farnell or associates" ?
BTW,I made the schematic using circuit lab,here it is https://www.circuitlab.com/circuit/dx43y5/arduino-theremin/,values in the schematic are not so correct(ignore them).

Correct me if I am wrong somewhere about the required components:

  • 2x Resistors ,each of 100k ohm

  • Capacitor C1 of value 150p of type NP0

  • Capacitor C3 and C4 of value 10p

  • Capacitor C2 of value 100n

  • Inductor L1 of value 10uH

  • IC1 {unknown mystery}


What IC is to be used,I still do not get it,the values are correct? and the schematic I made is also right?
The antenna made of wire is to be connected from "ANT" to "F _OUT" nodes?
The Male header pins are to be connected to +5V,2 ground connectors,and Vin
What is to be connected to Vin,the F Out or what?

abhishekk

Can someone help me sort out this prob. ?

dc42

Your schematic has some wrong component values. You need to use the values from the original circuit at http://interface.khm.de/index.php/lab/experiments/theremin-as-a-capacitive-sensing-device/. It shows there that the IC is a 74HC00N.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

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