Author Topic: OpenTheremin v3 for Tesla Coil  (Read 1883 times)

Offline profdc9

  • High Voltage Engineer
  • ****
  • Posts: 242
  • Karma: +12/-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: 1457
  • Karma: +24/-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
https://www.youtube.com/KaizerPowerElectronicsDk60/join - Please consider supporting the forum, websites and youtube channel!

Offline profdc9

  • High Voltage Engineer
  • ****
  • Posts: 242
  • Karma: +12/-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: 242
  • Karma: +12/-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: 147
  • Karma: +3/-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: LSI Nitrogen Laser tear-down and Homemade TEA Nitrogen and Dye Lasers
[Light, Lasers and Optics]
LesWright
August 06, 2020, 10:20:12 PM
post Re: LSI Nitrogen Laser tear-down and Homemade TEA Nitrogen and Dye Lasers
[Light, Lasers and Optics]
Weston
August 06, 2020, 08:45:59 PM
post Re: Cathodes in Compact Fluorescent Lamps
[Light, Lasers and Optics]
klugesmith
August 06, 2020, 05:41:04 PM
post Re: Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
Jun
August 06, 2020, 03:53:58 PM
post LSI Nitrogen Laser tear-down and Homemade TEA Nitrogen and Dye Lasers
[Light, Lasers and Optics]
LesWright
August 06, 2020, 03:28:14 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
AstRii
August 06, 2020, 12:59:03 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Mads Barnkob
August 06, 2020, 10:51:43 AM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
UB_Serpent
August 06, 2020, 08:40:57 AM
post Re: compact midi interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
TMaxElectronics
August 06, 2020, 03:22:38 AM
post Re: Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
davekni
August 05, 2020, 11:48:55 PM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
davekni
August 05, 2020, 11:37:13 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
AstRii
August 05, 2020, 08:01:11 PM
post Re: Fun with wireless power
[Solid State Tesla Coils (SSTC)]
Lightning On Demand
August 05, 2020, 06:34:08 PM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
Uspring
August 05, 2020, 12:56:32 PM
post Re: Fun with wireless power
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
August 05, 2020, 12:55:52 PM
post Re: Bipolar high voltage multiplier project - more than 70cm hot arc discharge
[Voltage Multipliers]
Teravolt
August 04, 2020, 09:21:09 PM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
johnf
August 04, 2020, 09:16:55 PM
post Re: Does anyone know how this site works.
[General Chat]
thedoc298
August 04, 2020, 05:53:03 PM
post Re: Does anyone know how this site works.
[General Chat]
thedoc298
August 04, 2020, 05:51:03 PM
post Re: Fun with wireless power
[Solid State Tesla Coils (SSTC)]
Lightning On Demand
August 04, 2020, 05:17:26 PM
post Re: Fun with wireless power
[Solid State Tesla Coils (SSTC)]
Max
August 04, 2020, 02:14:56 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
August 04, 2020, 02:08:07 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
futurist
August 04, 2020, 10:48:35 AM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
UB_Serpent
August 04, 2020, 10:02:39 AM
post Re: Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
Jun
August 04, 2020, 08:47:07 AM
post Re: Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
Jun
August 04, 2020, 08:43:00 AM
post Re: Does anyone know how this site works.
[General Chat]
Mads Barnkob
August 04, 2020, 08:33:47 AM
post Re: Does anyone know how this site works.
[General Chat]
MRMILSTAR
August 04, 2020, 05:09:26 AM
post Does anyone know how this site works.
[General Chat]
thedoc298
August 04, 2020, 01:54:49 AM
post Fun with wireless power
[Solid State Tesla Coils (SSTC)]
Lightning On Demand
August 03, 2020, 11:55:41 PM
post Re: Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
Teravolt
August 03, 2020, 09:17:40 PM
post Re: Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
MRMILSTAR
August 03, 2020, 08:30:38 PM
post Re: Budget USB cameras
[High Speed Filming]
missoum0514
August 03, 2020, 06:56:08 PM
post Re: Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
Jun
August 03, 2020, 05:23:15 PM
post Re: Is my xray transformer a ferrite core and how would I drive it?
[Transformer (Ferrite Core)]
nielsquake
August 03, 2020, 05:02:26 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
August 03, 2020, 04:31:04 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
futurist
August 03, 2020, 10:05:59 AM
post Re: Is my xray transformer a ferrite core and how would I drive it?
[Transformer (Ferrite Core)]
Mads Barnkob
August 03, 2020, 08:21:26 AM
post Re: Is my xray transformer a ferrite core and how would I drive it?
[Transformer (Ferrite Core)]
nielsquake
August 02, 2020, 11:45:38 PM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
davekni
August 02, 2020, 08:10:47 PM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
Uspring
August 02, 2020, 07:27:33 PM
post Re: Corona lockdown thread, tell about your situation
[General Chat]
Uspring
August 02, 2020, 07:14:17 PM
post Re: Is my xray transformer a ferrite core and how would I drive it?
[Transformer (Ferrite Core)]
nielsquake
August 02, 2020, 06:58:34 PM
post Re: current limiting to parallel resonance circuit
[Beginners]
davekni
August 02, 2020, 06:49:59 PM
post Re: Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
Jun
August 02, 2020, 05:10:12 PM
post Re: Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
MRMILSTAR
August 02, 2020, 04:55:14 PM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
UB_Serpent
August 02, 2020, 04:20:13 PM
post Re: How much is the voltage used in Corona Discharge tubes for ozone Generation?
[Transformer (Ferrite Core)]
UB_Serpent
August 02, 2020, 04:05:12 PM
post Dual MOT tesla coil
[Spark Gap Tesla Coils (SGTC)]
Jun
August 02, 2020, 01:07:54 PM
post current limiting to parallel resonance circuit
[Beginners]
plasma
August 02, 2020, 07:13:54 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 
SimplePortal 2.3.6 © 2008-2014, SimplePortal