Frequently Asked Questions

Basic Questions on the Open.Theremin

Q: What is an Arduino and where to get it?
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. Genuino is a different brand name used in Europe for Arduino and Genuino UNO can be used as well. You can buy Arduinos/Genuinos in online stores all over the world. See here for a list of stores:

Q: What type of Arduino should I get for the Open.Theremin shield?
A: The Open.Theremin is a shield for the Arduino.UNO, the most popular Arduino. Genuino is a different brand name used in Europe for Arduino and Genuino UNO can be used as well. The older Arduino Duemilanove should work as well. For the following Arduinos the software is not compatible (they do fit mechanicaly though): Arduino Leonardo. Arduino Mega. Avoid Arduino clones with ceramic resonator.

Q: What kind of antennas can I use?
A: As the Open.Theremin is quite flexible and can be easily tuned electrically 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 Open.Theremin?
A: Yes, this is possible. Thanks to Vincent Dhamelincourt who developed a MIDI implementation for the Open.Theremin V3. For code and instructions see here.

Questions on ordering kits.

Q: Do you sell kits?
A: Yes, I do sell assembled and tested Open.Theremin V3 shields. I produce in small batches. Please check the Small Batch Store for availability. The design is open source so you can also make modifications and improvements or even build the boards your self. I do not sell Open.Theremin.UP / RC / LC anymore and I do not sell plain circuit boards or parts.

Q: I don't have a paypal account, and I am not interested in having one, that's why I wanted to ask if a bank transaction also would be possible?
A: If you click on the "Buy Now" button in the store you will be redirected to the pay-pay website. There you can choose to pay with a debit or credit card without a pay-pal account. Would this work for you?

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: What kind of coils can be used?
A: The coil for the resonator circuit can basically be any 1000uH coil that fits. I noticed that some coils have a bigger temperature drift than others. Coils embedded in plastic seem to be more stable. From Reichelt L-PISG 1,0M might fit. To reduce temperature drift you could try to isolate the coil with some hot glue or similar.

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: Is my soldering ok?
Check your soldering. All pins need to be soldered properly. Make sure you have not shorted any pins. Also make sure that you plug in the shield to the Arduino correctly. All boards were tested and working properly before shipping.
For a good introduction to soldering and on how a good solder joint should look see "soldering is easy" by Mitch Altman.
Use this "Soldering Joint Quality Chart" I made to see if your soldering is ok. The first two is what you are aiming for.

Q:  Why do I have strange tone vibration on low frequencies (like buzzing flies, around note E).
You may be using a Arduino clone with a cheap ceramic resonator instead of a quartz crystal. Replace your Arduino with an original Arduino. Or then try to replace the oscillator yourself as shown here. (Thanks to Sergey Anokhin for figuring this out.)

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.

Notes to be clear

Open source hardware pioneer Limor Fried uses to said "being obscure is the enemy" of OSHW projects and I agree with this. This is why if you feel something is missing or if you are stuck with a problem, don't hesitate and please just ask.