Since the first version of the software is now complete I was thinking this might be a good occasion to summarize the features and functions of the Bi-Onda TT motor controller as they are now implemented. I must admit I had an idea for a new feature last night but I will keep this on the back burner for now. Gotta stop somewhere.
So let's take a look at the feature list.
- Dual DDS sine wave generation.
- Adjustable frequencies with a resolution up to 0.01 Hz.
- Micro controller DDS generation, 16MHz quartz clock, interrupt driven
- Chebyshev low pass filters
- Power Op-amp amplification up to +-15V with transformer boost to 120+VAC
- Adjustable output levels
- LCD 16x2 character backlit display
- 33.3 & 45 RPM speed generation
- EEPROM storage of calibration settings
- Remote expansion header to allow incorporation of all, or some, operating buttons into the turntable, parallel to the buttons on the Bi-Onda.
User selectable operating modes:
- Continuous always-on mode with single or dual sine wave out as mains source
- Switchable on-off mode with dual sine wave, phase shifted for direct drive of motor coils
- Calibrated sine output for 33.3 and 45 RPM operation
- Speed selection
- Speed adjust with selectable resolution: 1.0Hz, 0.1Hz, 0.01Hz (during play and in CAL mode)
- Incr Decr speed buttons
- Motor acceleration startup (spin-up)
- 33.3 RPM Calibration
- 45 RPM Calibration
- Phase Shift adjustment (1.4 degree steps)
- Operating Mode selection
- Acceleration Mode (on or off)
- Acceleration Parameter Adjust (start frequency, frequency step, step delay)
This should pretty much cover most needs as a power source upgrade or for custom turntables. The one thing left to do is determine the total power handling capacity based on the components (op-amps, transformers, etc.) currently in use and possible alternatives to drive motors with lower voltage requirements or motors with higher wattage ratings.