Many of us have Premotec, McLennan etc 230/110v ac syncronous motors driving our TT's. The professional controllers are expensive (and possibly rightly so). So a good (free) flexible controller design with PCB layouts is possibly long over due.
The last good one I saw used PIC controllers and was 10 years ago.
Now we have Aduino boards (and other brands) that are cheap as chips.
Has any one done any design work with these. Seems it will be easy to have a display, controls etc.
Assuming the audio output is fed to a couple of chip amplifiers, should be simple to control frequency (speed) voltage and phase shift, with or without step up transformers.
I would be keen to follow this up (need controller for new TT)
but dont have the nouse to ensure all componets will work together without creating smoke.
I'm sure there will be at lot of interest for this project!
If this is already done could someone point me in the right direction.
The last good one I saw used PIC controllers and was 10 years ago.
Now we have Aduino boards (and other brands) that are cheap as chips.
Has any one done any design work with these. Seems it will be easy to have a display, controls etc.
Assuming the audio output is fed to a couple of chip amplifiers, should be simple to control frequency (speed) voltage and phase shift, with or without step up transformers.
I would be keen to follow this up (need controller for new TT)
but dont have the nouse to ensure all componets will work together without creating smoke.
I'm sure there will be at lot of interest for this project!
If this is already done could someone point me in the right direction.
There's a bunch of ways to make a design. I've seen at least a few designs (though not necesarily using a microcontroller) mentioned around here. For hardware to drive the motor, the most basic is a small audio power amp feeding a transformer (a filament transformer may work, or the transformer from an uninterruptible power supply should surely work) to get the voltage up to power a 120V motor. You could use high voltage transistors, probably MOSFETS, and a 150V supply to drive the motor directly.
For the signal, I've read others here use an ipod with the desired frequency recorded on it. You can generate the desired frequency with Audacity or other audio editing software, and either convert to mp3 and transfer, or play the tone through the computer's sound output and record it directly on the ipod.
There's a bunch of ways to program a microcontroller to generate the frequency, but this is The Best Way:
Numerically controlled oscillator - Wikipedia, the free encyclopedia
A (nearly completely) hardware solution would use a direct digital synthesis chip, normally used for RF signal generation. These are just a hardware implementation of direct digital synthesis. I recall that Analog Devices makes several models of DDS chips. These can generally set frequency to a resolution of 0.001Hz or so, depending on internal register size and the crystal frequency you use. It still needs a microcontroller to load up the registers with the desired values.
This is just one of a long list of projects I've wanted to do. The same ideas can be used to generate three-phase signals for a direct drive turntable, and that's on my list too.
For the signal, I've read others here use an ipod with the desired frequency recorded on it. You can generate the desired frequency with Audacity or other audio editing software, and either convert to mp3 and transfer, or play the tone through the computer's sound output and record it directly on the ipod.
There's a bunch of ways to program a microcontroller to generate the frequency, but this is The Best Way:
Numerically controlled oscillator - Wikipedia, the free encyclopedia
A (nearly completely) hardware solution would use a direct digital synthesis chip, normally used for RF signal generation. These are just a hardware implementation of direct digital synthesis. I recall that Analog Devices makes several models of DDS chips. These can generally set frequency to a resolution of 0.001Hz or so, depending on internal register size and the crystal frequency you use. It still needs a microcontroller to load up the registers with the desired values.
This is just one of a long list of projects I've wanted to do. The same ideas can be used to generate three-phase signals for a direct drive turntable, and that's on my list too.
3GGG's AC Sync motor control
Does anyone know if 3GGG is still around?
In 2010 his brother designed and built a wonderful controller for sync motors. Does anyone have a copy?
I scanned all of 3GGG's threads, there were some final pics posted of his TT (beautifully built 3GGG) but I could only see the first pic so dont know if he posted the controller diagram amongst those.
Does anyone know if 3GGG is still around?
In 2010 his brother designed and built a wonderful controller for sync motors. Does anyone have a copy?
I scanned all of 3GGG's threads, there were some final pics posted of his TT (beautifully built 3GGG) but I could only see the first pic so dont know if he posted the controller diagram amongst those.
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