Author Topic: OpenTheremin v3 for Tesla Coil  (Read 1331 times)

Offline profdc9

  • High Voltage Engineer
  • ****
  • Posts: 232
  • Karma: +11/-0
    • View Profile
OpenTheremin v3 for Tesla Coil
« on: May 29, 2018, 07:01:20 PM »
So I built my theremin and while it works, it is not the greatest.  As predicted, the RC-based theremin is a good noisemaker but is hard to control.

So instead, I am going to modify OpenTheremin v3 to directly be an interrupter.  I laid out the board for thru-hole, which I have attached.  A picture of the board is here:



Since there are no thru-hole varactors anymore as far as I can tell, I used four 1N4001 in parallel which roughly has the same capacitance as the varactors used in the OpenTheremin (BB914).

I also got rid of the Arduino and just put the Atmega328 on the board itself, as well as the power supply, so it is self contained, and I added a circuit to output the MIDI.

Dan

Offline Mads Barnkob

  • Administrator
  • High Voltage Expert
  • *****
  • Posts: 1179
  • Karma: +17/-0
  • Denmark
    • View Profile
    • Kaizer Power Electronics
Re: OpenTheremin v3 for Tesla Coil
« Reply #1 on: June 01, 2018, 03:16:23 PM »
Did you get any videos done of using the RC theremin on a DRSSTC?

Did you use the MIDI "hack" that someone else already made for the OpenTheremin?
http://www.kaizerpowerelectronics.dk - Tesla coils, high voltage, pulse power, audio and general electronics

Offline profdc9

  • High Voltage Engineer
  • ****
  • Posts: 232
  • Karma: +11/-0
    • View Profile
Re: OpenTheremin v3 for Tesla Coil
« Reply #2 on: June 01, 2018, 04:12:22 PM »
I haven't got any video yet, I am behind in my work because I have been playing too much :) but maybe this weekend if the weather cooperates I can get some video.

I added a couple of things to the board.  One is an output for the MIDI using the TX of the AVR (which does double duty as if the ATmega328p is flashed with the Arduino bootloader, you can use a serial port interface to flash the mega as well).  I also added a LM386 to the board so you can get a low power amplified output directly from the board, and you don't need an external amplifier if you just want to use it as a portable Theremin.



The revised project is attached.

Dan

Offline profdc9

  • High Voltage Engineer
  • ****
  • Posts: 232
  • Karma: +11/-0
    • View Profile
Re: OpenTheremin v3 for Tesla Coil
« Reply #3 on: June 28, 2018, 04:01:13 AM »
Hello,

I built an OpenTheremin v3 based on only thru-hole parts.  The PCB is below.



It works, but I had to experiment a bit to find diodes that work as varactors.  Unfortunately, there are no available thru-hole varactors anymore.  I figured out that I could use three 10A10 diodes in parallel in place of the varactor.  I'm sure it wouldn't work for RF, but it seems to do ok for the Open Theremin.  I had to use three 10A10 diodes and then add 50-100 pF of capacitance in parallel with that, and then the autotune works.  I modified the board so it can take large diodes in case these are needed as the varactors.

The board I laid out also includes MIDI output (hooked up to a DIN-5 connector) and a small amplifier (LM386), as well as putting the ATMEGA328P on the board so an Arduino Uno is not required.  There is also a place for a IFE97 fiber optic LED which will be used for generating an interrupter output.  It should be possible to modify the standard OpenTheremin v3 to have an interrupter output, as I'm just going to retask one of the LEDs as the interrupter output (the green one).

Probably the 10A10's are less temperature stable than the BB914 diodes but after 15 minutes or so of being turned on the calibration stabilized.

One question I have about the OpenTheremin is that it seems like the volume is muted by putting one's hand closer to the volume antenna.  Is this the way it is supposed to be?

Anyways the Kicad project is attached.

Dan





Offline futurist

  • Global Moderator
  • High Voltage Technician
  • *****
  • Posts: 116
  • Karma: +0/-0
    • View Profile
Re: OpenTheremin v3 for Tesla Coil
« Reply #4 on: July 01, 2018, 03:00:17 PM »

One question I have about the OpenTheremin is that it seems like the volume is muted by putting one's hand closer to the volume antenna.  Is this the way it is supposed to be?

Yes, it should work like that

Firmware has debug mode and I think it's still not documented, but it might help you to see if everything is working correctly. If you open the serial window in Arduino IDE and set 115200 baud rate and then start the calibration of your theremin you should get the calibration data.  Calibration range is from 0-4096 and you can check if your oscillators are in the range

Did you test it with your DRSSTC?


High Voltage Forum

Re: OpenTheremin v3 for Tesla Coil
« Reply #4 on: July 01, 2018, 03:00:17 PM »

 


* Recent Topics and Posts

post Re: My first DRSSTC on bricks
[Dual Resonant Solid State Tesla coils]
Laci
Today at 08:35:24 PM
post Re: How To Make a Stencil For Spray Paint With Cheap Hand Tools
[General chatting]
johnf
Today at 07:53:35 PM
post Re: Duty cycle when driving a CRT TV flyback transformer
[Transformer (ferrite core)]
John123
Today at 02:52:58 PM
post Re: Royer oscillator (ZVS) driven Jacob's ladder, E80 core transformer
[Transformer (ferrite core)]
John123
Today at 02:42:19 PM
post Re: Full bridge much "weaker" than half bridge?
[Solid state Tesla coils]
nick
Today at 11:17:36 AM
post Re: Royer oscillator (ZVS) driven Jacob's ladder, E80 core transformer
[Transformer (ferrite core)]
davekni
Today at 04:51:08 AM
post Re: Duty cycle when driving a CRT TV flyback transformer
[Transformer (ferrite core)]
davekni
Today at 04:26:22 AM
post Re: How To Make a Stencil For Spray Paint With Cheap Hand Tools
[General chatting]
AndreiRS
Today at 01:21:35 AM
post Re: Using same winding on separate rails?
[Transformer (iron core)]
Twospoons
December 11, 2019, 10:49:04 PM
post Re: A dynamical arc model v2
[Dual Resonant Solid State Tesla coils]
Uspring
December 11, 2019, 05:28:46 PM
post Re: Full bridge much "weaker" than half bridge?
[Solid state Tesla coils]
Fumeaux
December 11, 2019, 03:11:42 PM
post Re: Royer oscillator (ZVS) driven Jacob's ladder, E80 core transformer
[Transformer (ferrite core)]
John123
December 11, 2019, 02:22:10 PM
post Re: Duty cycle when driving a CRT TV flyback transformer
[Transformer (ferrite core)]
John123
December 11, 2019, 02:09:19 PM
post Full bridge much "weaker" than half bridge?
[Solid state Tesla coils]
nick
December 11, 2019, 01:10:57 PM
post Re: Possible use for large inductor (laminated core)
[Transformer (iron core)]
kamelryttarn
December 11, 2019, 08:48:36 AM
post Re: SGTC MK1 - An Accomplishment in Progress
[Spark gap Tesla coils]
davekni
December 11, 2019, 06:08:48 AM
post Re: SSTC low voltage at gate transformer and heating drivers
[Solid state Tesla coils]
davekni
December 11, 2019, 05:38:17 AM
post Re: Duty cycle when driving a CRT TV flyback transformer
[Transformer (ferrite core)]
davekni
December 11, 2019, 05:01:31 AM
post Re: Using same winding on separate rails?
[Transformer (iron core)]
John123
December 11, 2019, 01:52:43 AM
post Re: Using same winding on separate rails?
[Transformer (iron core)]
klugesmith
December 11, 2019, 01:41:04 AM
post Re: Worlds Weirdest Microwave Oven, From A Weapons Factory - The Husqvarna Cupol
[Transformer (iron core)]
klugesmith
December 11, 2019, 01:37:13 AM
post Re: Using same winding on separate rails?
[Transformer (iron core)]
John123
December 11, 2019, 01:19:58 AM
post Re: SGTC MK1 - An Accomplishment in Progress
[Spark gap Tesla coils]
jturnerkc
December 11, 2019, 01:14:32 AM
post Re: Using same winding on separate rails?
[Transformer (iron core)]
klugesmith
December 11, 2019, 01:04:08 AM
post Re: SSTC low voltage at gate transformer and heating drivers
[Solid state Tesla coils]
babass
December 10, 2019, 11:24:50 PM
post Using same winding on separate rails?
[Transformer (iron core)]
John123
December 10, 2019, 10:52:50 PM
post Re: Duty cycle when driving a CRT TV flyback transformer
[Transformer (ferrite core)]
John123
December 10, 2019, 03:35:40 PM
post Re: Why did 4HV die??
[General chatting]
John123
December 10, 2019, 03:21:07 PM
post Re: Duty cycle when driving a CRT TV flyback transformer
[Transformer (ferrite core)]
Mads Barnkob
December 10, 2019, 03:04:28 PM
post Re: Duty cycle when driving a CRT TV flyback transformer
[Transformer (ferrite core)]
John123
December 10, 2019, 02:57:45 PM
post Re: Possible use for large inductor (laminated core)
[Transformer (iron core)]
kamelryttarn
December 10, 2019, 11:23:48 AM
post Re: SGTC MK1 - An Accomplishment in Progress
[Spark gap Tesla coils]
Mads Barnkob
December 10, 2019, 10:27:54 AM
post Re: Worlds Weirdest Microwave Oven, From A Weapons Factory - The Husqvarna Cupol
[Transformer (iron core)]
Mads Barnkob
December 10, 2019, 10:20:17 AM
post Re: Possible use for large inductor (laminated core)
[Transformer (iron core)]
Mads Barnkob
December 10, 2019, 10:16:32 AM
post Re: SGTC MK1 - An Accomplishment in Progress
[Spark gap Tesla coils]
davekni
December 10, 2019, 06:04:28 AM
post Re: Duty cycle when driving a CRT TV flyback transformer
[Transformer (ferrite core)]
davekni
December 10, 2019, 05:28:54 AM
post Re: Possible use for large inductor (laminated core)
[Transformer (iron core)]
davekni
December 10, 2019, 04:12:29 AM
post Duty cycle when driving a CRT TV flyback transformer
[Transformer (ferrite core)]
John123
December 09, 2019, 10:52:59 PM
post Replacement guide for Windows Media Center
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
MRMILSTAR
December 09, 2019, 08:29:16 PM
post Re: Sense coil fabrication?
[Induction launchers, coil guns and rails guns]
Uspring
December 09, 2019, 04:23:33 PM
post Re: Possible use for large inductor (laminated core)
[Transformer (iron core)]
MRMILSTAR
December 09, 2019, 03:59:02 PM
post Re: SGTC MK1 - An Accomplishment in Progress
[Spark gap Tesla coils]
jturnerkc
December 09, 2019, 03:41:42 PM
post Possible use for large inductor (laminated core)
[Transformer (iron core)]
kamelryttarn
December 09, 2019, 09:43:11 AM
post Re: SGTC MK1 - An Accomplishment in Progress
[Spark gap Tesla coils]
davekni
December 09, 2019, 12:53:57 AM
post Re: CW multiplier resistor string suggestions
[Voltage Multipliers]
davekni
December 08, 2019, 09:57:51 PM
post Re: CW multiplier resistor string suggestions
[Voltage Multipliers]
MRMILSTAR
December 08, 2019, 05:28:09 PM
post Aethra CCD Webcam Teardown - From Back When Streaming Was Expensive!
[Electronic circuits]
Mads Barnkob
December 08, 2019, 01:33:30 PM
post Platter resistance & inductance
[Induction launchers, coil guns and rails guns]
klugesmith
December 08, 2019, 11:41:00 AM
post Re: CW multiplier resistor string suggestions
[Voltage Multipliers]
davekni
December 08, 2019, 06:50:11 AM
post Re: CW multiplier resistor string suggestions
[Voltage Multipliers]
plasma
December 08, 2019, 12:00:00 AM

Sitemap 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30