Andrey Smirnov :: workshops

Theremin Sensors Circuitry

Analog T-Sensors, based on classical theremin heterodyning principle, where realized in 1999-2003. I used specialy developed circuitry to produce super sensitive control. There were two basic versions of sensors:
t-sensors to detect the distance, providing the audio output with the pitch related to the distance between the body and antenna; t-sensors to mesure velocity of changes (body movement near antenna, air flow, water drops near antenna etc.).
Sensor and receiver were separated and connected to each other with the long cable (25 m.) to work with the distant sensitive objects in the interactive installations, to analyse the motion of the dancers or performers on the stage etc. All controls were built in a receiver, normaly located near the operator's computer.
Main advantage - NO NEED IN TUNING ON THE STAGE. Any adjustment could be realized by operator even during the performance, which was very important for any interactive audio/video installations and live performance situation.
Most recent digital USB D-Sensors, developed in 2005-2006, are based on alternative Direct-Control principle.
Unlike any classical theremin designs and previous T-Sensors, they have one main advantage - NO ANALOG TUNUNG IS NEEDED AT ALL! After any change of hardware configuration system produce self adaptation and tuning by software means.
Any conductive media could be connected to the sensors as an antenna: metal objects, foil, water, human body, plants and vegetables, metal threads, thin plastic films with metallization, all sorts of Christmas stuff, conductive fabrics and clothes etc. to monitor variations of air flows, mechanical vibrations, changes of electrical capacitances of different conductive medias etc. And no need in screwdriver to fight with coils! Just plug and play. D-Sensors are ideal for live interactive performance and long term interactive audio/video installations to avoid any need in continuous maintenance by the personal.
We also could call them PLUG-AND-PLAY THEREMIN.

Theremin Sensor Kit

The Sensor Kit contains the basic universal D-sensor circuitry oriented on both USB and Analog systems. convenient in case you need to analyse the motion of the dancers and performers on the stage or to work
Any conductive media could be connected to d-sensor as an antenna: metal objects, foil, water, human body, plants and vegetables, metal threads, thin plastic films with metallization, all sorts of Christmas stuff, conductive fabrics and clothes etc. to monitor variations of air flows, mechanical vibrations, changes of electrical capacitances of different conductive medias etc. D-sensors are ideal for live interactive performance and long term interactive audio/video installations to avoid any need in continuous maintenance by the personal.

Analog Theremin Sensor#1

This sensor is convenient in case you need to analyse the motion of the dancers and performers on the stage or to work with the distant sensitive objects in the interactive installation. The sensor is providing the output voltage proportional to the velocity of changes (body movement near antenna, air flow etc.). Sensor and receiver are separated. They are connected to each other with the long cable (25 m.). All controls are located at receiver side.

Sensor:

U1 - 4049 or 4069 (six CMOS invertors)
Capasitors C1, C2 - NP0 class (temperature stable).
L1 - selfmade.
Prototyping board and plastic case are available at Chip and Dip store (in Russia) or any other electronic store.


Receiver:

It is important to match frequencies of sensor oscilator and receiver oscilator. They should have similar initial values. The relation of the frequency of receiver oscilator and it's inductance L1 will be as following: 6.8 mH (milli Henri) will give you approximetely 130 khz, 1.8 mH - 230 khz, 0,5 mH - 370 khz, 0.44 mH - 500 khz, 0.27 mH - 800 khz, 0.082 mH - 1 mhz.

Analog Theremin Sensor#2

This sensor is convenient in case you need to analyse the motion of the dancers and performers on the stage or to work with the distant sensitive objects in the interactive installation etc. This sensor is providing the audio output with the pitch related to the distance between the body and antenna. Sensor and receiver are separated. They are connected to each other with the long high frequency cable (25 m.). All controls are located at receiver side.

Sensor:

Q1, Q2 - high frequency transistor BC847, 2N2222, 2SC380 or any similar.
Capasitors C2, C3 - NP0 class (temperature stable).
L1 - selfmade.
Prototyping board and plastic case are available at Chip and Dip store (in Russia) or any other electronic store.

Receiver:

It is important to match frequencies of sensor oscilator and receiver oscilator. They should have similar initial values. The relation of the frequency of receiver oscilator and it's inductance L1 will be as following: 6.8 mH (milli Henri) will give you approximetely 130 khz, 1.8 mH - 230 khz, 0,5 mH - 370 khz, 0.44 mH - 500 khz, 0.27 mH - 800 khz, 0.082 mH - 1 mhz.

Q1, Q2 - high frequency transistor KT315 (Russian) BC847, 2N2222, 2SC380 or any similar.
Capasitors C5, C6 - NP0 class (temperature stable).
L1 - any stable coile with apropriate inductance.
U1 - uA776 or Russian KP140UD1208 or any similar operational amplifier. It is also possible to use uA741 if you remove R13.
C10 - NP type capasitor.
Power: any power supply +- 10 v (7810 & 7910 types).
Prototyping board and plastic case are available at Chip and Dip store (in Russia) or any other electronic store.

Learn More:

Theremin Sensors

Theremin Sensors Workshop

Dealing with Theremin Sensors: pinouts and connections

Multichannel interfaces

Theremin Sensors Circuitry

Theremin Coil construction

Tests and troubleshooting

Classical Theremins

Extra Links:

Watch video of lectures at Hangar, Barcelona, June 2007

Thereminvision

All service manuals and data sheets, sorted on make and model