Motor control for turntable possible?

ESPHome
1

Hi!
I am new to both home-assistant - and i have stumbled upon esphome - which has got me thinking of all kinds of things that i want to automate.

I am a bit of an “audiophile” - and i like to listen to oldschool records.
My record player is upgraded with a dc motor - from a company called origin live.
That means my Turntable is driven by a DC motor. The specification of the motor is not named - but it is hear say that they are of type A-max 110173 from maxon.

I believe it’s a brushless motor.

Today i have an external psu - that goes into the Origin Live controlbox - and from there flows the current to the motor.

The control is really simple - as i only has 2 “modes” 33 and 45 rpm - they are “tuned” by 2 variable potentiometers - that i can turn in either direction - to control speed of the currrent setting.

the psu is 12

without knowing much about electronics - it seems that they simply change the voltage going to the motor - and depending on voltage - the motor will run in the “correct” rpms

There are no verification - so i have to manually adjust it to the right speed.

i dont know if there is more to it than this - if so - would i be possible to create an esphome (esp32) with some sort of motor controller board - where you can control the output?

because- then i could control the speed from inside home-assitant - and of course - turning it on an of etc.

Br
Ronni

2

How do you know when it is going the right speed? Simply by ear?

3

Some turntables have stroboscopic markings along their outer edge, with a small lamp to illuminate them.

4

They do. The original motor drive turntables had them, for this exact reason. But this has been converted to motor drive.

You could paint some lines on the outside, shine a light and measure reflexion, the rate would translate to rpm.

5

Hang on, I’m not certain how you’d get a rotating field from a brushless dc drive in the first place.
If you have a magnetic core (heavy) you’d need a rotating field and if you have a Squirrel cage you’d still need a rotating field. So this makes no sense.

Surely all you want is a switch to turn it on and another switch to select between speeds. The manual potentiometers remaining in place.

Though why you’d want to is beyond me, the act of removing a record from its sleeve, placing it on the deck, cleaning the disc and removing static is surely a pre-requisite to playing a record. I don’t see what an automated switch brings you apart from detracting from the magic.

I have a Sondeck, I wouldn’t go near this modification

Edit: In effect what is being talked about is a continuous ‘stepper motor’, where the current is switched between poles in the stator, the magnets (can be rare earth to reduce weight and increase efficiency) in the rotor. This would have a pulsating torque profile, but I assume that is catered for by the size of the flywheel (turntable in this case)
I still wouldn’t do this modification.

6

Hi All.
Thanks for your replies.
I think i will drop this project - for the time being -
i have a lot of other cool things that i would like to integrate :slight_smile: