DIY Motorized roller base

[Dirk Rösler]

How about just constantly or periodically varying rotation speed ever so slightly?

[Henrim]

How about just constantly or periodically varying rotation speed ever so slightly?

I have thought that too. I'm going to experiment with that if I get uneven results.

[Ari]

FWIW, mine only goes in one direction, and results are always great in Jobo tanks.

[Jordan]

I have always wished someone would build something like this for the expert drums. I would happily buy one as I'm sure many would.

[Ari]

I have always wished someone would build something like this for the expert drums. I would happily buy one as I'm sure many would.

I use a Unicolor and Simma-roller with Expert tanks, they were each under $50.
Not to take away from the splendid work Henri has done, but the motorized bases are very affordable if you can't (like me) or won't build your own.

[Colin Graham]

Very cool project. What size stepper did you use? A 125 oz/in NEMA 23 like this one- https://www.sparkfun.com/products/10847?

I did something similar, but with a DC gearmotor and a PWM board with reversing rocker switch and pot. I had a hard time deciding between an Arduino and the 'dumb' controller board, so looking forward to seeing how your project turns out.

[Jordan]

Ari,
I agree that those are viable options and actually work pretty good. I do have a processor that I use now with one of the newer motors. However, I find it's really not all that necessary over the motor bases other than being a bit more convenient. If someone could just offer something in between the motor base and full processor it would be ideal.

I use a Unicolor and Simma-roller with Expert tanks, they were each under $50.
Not to take away from the splendid work Henri has done, but the motorized bases are very affordable if you can't (like me) or won't build your own.

[Ari]

Ari,
I agree that those are viable options and actually work pretty good. I do have a processor that I use now with one of the newer motors. However, I find it's really not all that necessary over the motor bases other than being a bit more convenient. If someone could just offer something in between the motor base and full processor it would be ideal.

Got it, Jordan; that makes sense.

[Drew Wiley]

It's always been my opinion that the standard Jobo motors have less than ideal gear ratios. They run too fast with insufficient power for larger solution volumes.
I don't know why any developing process needs that kind of RPM, and for some things it's a distinct disadvantage. 30 RPM is plenty fast, though I tend to rev
the speed up for rinse cycles. Dual-direction rotation is sometimes helpful, and I too have that feature on my roller drives. But one distinct improvement over any of em that I employ is that one out of the four rollers is eccentric, so that it very slightly rocks the linear direction of the drum with each rotation, hence minimizing the risk of streaks along the plane of rotation. Some processes are more finicky than others, so it's helpful to have various options on the drive system.

[onnect17]

I think 30rpm is on the low side. Actually, the CPE2 plus eliminated the 25rpm speed and left the 75rpm only. Not sure I would use an Arduino for this project. Perhaps a good DC motor and a 555 would do.

Also take a look in the torque capacity of the motor (if not geared). The load is considerable big for sustained operation.