Frequently Asked Questions

Questions on ordering kits.

Q: Do you sell kits?
A: Yes, we do sell assembled and tested Open.Theremin shields. Boards are produced in small batches. Please check our online shop for availability. The design is open source so you can also make modifications and improvements or even build the boards your self. We do not sell Open.Theremin.UP / RC / LC and OpenTheremin V3 anymore and we do not sell plain circuit boards or parts.

Q:Will there be extra duties or taxes for my country
We ship worldwide. Specific duties and taxes for you country may apply and are to your responsibility.

Q: How long will shipping take to my place
Shipping time varies a lot and is dependent on the country, the season and the custom checks. All theremins are shipped within 1 week by Swiss Priority mail. Please expect 1-2 weeks extra for the shipping. We had theremins that arrived in Japan in 4 days. German custom seems to be rather rigorous and may delay the shipment up to one week.

Q: Is there a tracking number for my shipment
There is no tracking number with the free shipping orders. If you prefer registered shipping with tracking number, this costs extra 6 Euro. Please choose the "registered shipping" option for you order.

More technical questions & trouble shooting

Q: The volume antenna does not seem to work
Make sure the theremin is grounded well. This can  be a reason for the volume antenna not working well. See the instructions for different grounding methods.

Q:  Why do I have strange tone vibration on low frequencies (like buzzing flies, around note E).
Some USB adapters are of poor quality and produce noise on the power lines. If you experience noise in the audio signal try with a different USB adapter.

Q: How can I upload a new software version to my OpenTheremin?
Find a detailed instruction on how to update the software on your Theremin here.

Q: Is the software on my OpenTheremin up to date?
You can check the installed software version and the code settings by reading the "Calibration Diagnostics" - see how in the next question.

Q: The pitch or volume antenna does not seem to be calibrated properly?
You can check the calibration data using the built in "Calibration Diagnostics" - here is how to do it.

Q: I have a cracking sound on the audio after updating the software of my OpenTheremin . Why?
What you hear is the gate signal on the second channel of the audio. See here for more info on GATE and CV. You can remove the cracking sound by turning off the gate. To do so change the following lines in the file build.h to: #define GATE_ON 128 #define GATE_OFF 128

Q: Can I used different antennas?
A: As the Open.Theremin has an automatic calibration it can adapt to different types and sizes of antennas. You can use almost any electrically conductive material as an antenna. The boards are optimized and tested for aluminium rods, 6 mm diameter and 50 cm long. Thicker, thinner and slightly longer and shorter antennas should work well also.

Q: What if I want to increase the distance between the antennas.
A: You can just put a piece of wire from the antenna pad on the circuit to the antenna is self. The wire should not be too long (<50 cm) as it adds to the length of the antenna. Best is to use stiff wire to prevent the wire from moving around in your case and thus changing the signal.

Q: How can I reprogram the wave lookup table?
A: If you open the open.theremin software with the arduino programming environment (IDE) you should find one tab named "theremin_sintable.c" that contains the values for the wave form. There are 1024 values that define the wave, each can take values between 0 and 2048. Just change the numbers and upload the software to the theremin.

Q: is MIDI possible with the OpenTheremin V4?
A: Yes. A special code developed by Vincent Dhamelincourt adds MIDI functionality to the OpenTheremin V4. For code and instructions see here.

Q: What does Arduino compatible mean?
A: Arduino is a widely used single-board micro-controller to make using electronics in multidisciplinary projects more accessible. The hardware consists of an open-source hardware board designed around an 8-bit Atmel AVR micro-controller. Many projects and product are based on the Arduino witch makes the board a well documented and easy to use standard in open source electronics. The OpenTheremin V4 is based on the open design and the software and bootloader are compatible with Arduino UNO. For more information see