The Free MagicQuartz Arduino Version
Here is the MagicQuartz Arduino version! It is free (but closed source) and based on standard Arduino hardware, which is available everywhere. To build it, you do not need to buy anything from me. The Arduino version is fully functional, except for some technical limitations:
- No autonomous operation – requires a computer to work. Of course I want you to buy the “real” DIY kit :-), but the serial communication with the PC really makes things much easier and cheaper. However, as the real version, it also resumes to the last mode of operation after a power breakdown. This allows you to – theoretically – operate it without a computer, after it has been set up. You only would need the computer to change the speed or mode of operation. I can’t guarantee, however, that this works in the long run.
- No power monitoring: less security features, does not adjust the voltage to load changes.
- The first motor shield version generates only about 180V with a very poor sine wave quality (but it works surprisingly well). The second breadboard version is capable of delivering 220V with a high-quality sine wave.
- Limited precision: not clocked from a quartz crystal, but from a ceramic resonator and it does not use the advanced GCD Time Interleaving Algorithm, therefore it does not provide a 1/10,000 Hz/RPM resolution. This is a technical restriction that is necessary to keep the serial communication with the computer intact.
Also be aware of some serious hazards:
- Please use an USB isolator between your computer and the Arduino. If you don’t, the whole circuit may blow your computer’s USB port or the whole computer (e.g. in the unlikely event of a failure of the amplifier chip). You can find such isolators (e.g. based on the ADUM4160 chip) on eBay.
- Never ever use a lithium battery (e.g. one of those USB powerpacks) to power the Arduino. In the unlikely event of a failure, it may explode.
There are two variants that you can build. The first one is based on the Arduino Uno in combination with the official Arduino Motor Shield. It is easy to build because it is basically “plug&play”. However, the sine wave quality is rather poor. If you want want to evaluate how well the real MagicQuartz will work with your turntable, I recommend to build the breadboard version. It is also very easy to build – and much cheaper.
Follow these two links for the two variants: