Hi!

I have a couple of MyFocuserPro focus controllers, but need to get a new one. And I would like a small, simple controller. I really like the Tic-focuser (github.com/sebo-b/TicFocuser-ng) butit is based on a controllerboard that only is sold in the US, as I understand it, making it quite expensive to buy for an European. And of course, the controller would need to be INDI-compatible.

Any suggestions and great ideas?

Magnus

www.rigelsys.com/focuser.html

Website is a bit 1990s but the products are good. Designed to fit stock focusers too and if he doesn't have an adapter he's a machinist and can make it happen for you. I use one on my C11 Edge and it's awesome (no crayford req'd). I also own his rotator; it's really simple and much cheaper than the mass-produced Pegasus ones.

He does have INDI drivers.

Hi Magnus,
I bought a Tic-500 controller for about 25€ on Ebay. Yes, it's more expensive than in the US but it was still OK. I'm European too
Then I built myself a focuser:
MagneTicFocuser

CS
Lucas

Hi Lucas!

Great, that looks very interesting! I must admit I am not an engineer and a bit unsure about both the mechanics and the electronics here. Part of my current problem (beside ageing controllers) is that my latest camera (QHY268m) plus OAG and filterwheel stresses my current stepper motor too much and it fails at times. You seem to have experienced similar problems with your first 5:1 planetary gear motor. Maybe I should also go for a 27:1 gear instead - however, that gives me more steps in the ciritical focus zone that I would like. So two questions: have you calcualted your number of steps in the critical focus zone, and do you have any idea of how much torque is really needed (I can not figure out how to calculate that)?

For the controller: I found one on EBay, sold from UK. Including shipping and tax, that would be about EUR 50. Yours sound cheaper - got a link for it?

Magnus

]Hi Magnus,

no, I didn't do any step count calculations. EKOS does this very well. Torque is not a problem with the 27:1 gearbox. Even with only 1mA at 12V there is more than enough torque for such setups. My camera is hanging upside down on the Newton and the focuser has no problem with it.
I bought the controller here: Tic T-500https://www.ebay.de/itm/132580666482 (20,12€)

CS
Lucas

You don't say what kind of computer you're using. If you're using a Raspberry Pi or compatible, you could try the Waveshare Stepper Motor HAT. It plugs straight into the GPIO header on the Pi, and you just wire a stepper motor directly to it. You just need to rig up a way to mount the stepper motor to the telescope's focuser. As a bonus, it eliminates the need for a separate 5v supply for the Pi.

Vote 2 for the Waveshare if you are using the RaspberryPi.

I got it and a stepper motor from a local electronics shop and it cost me ~$50 to add autofocus to my rig.

Kavin & Radon,

That's interesting! I do have Raspberries at my scopes, running Stellarmate. Didn't know about this HAT, was only thinking Arduino.

So this HAT goes on the R-Pi, and directly connects to the motor - how then do I control it with Ekos? Some separate driver would be needed, wouldn't it?

And: how do you handle this mechanically? Using the same R-Pi to control the focuser as for running everything else, or a separate on? If the same, you'd need to place it close to the focuser, right - any good designs for that? (including then of course some kind of case for the R-Pi + HAT that is dew safe and cools the R-Pi)

Magnus

I build several simple focusser.-controllers based on Arduino-NANO from this source: github.com/fehlfarbe/arduino-motorfocus
Used always the simple stepper-motor.

Cheers
Hardy

Hi Hardy!

Yes, that is really interesting! I think I've seen that before but could not find it now. Simple and straightforward, it seems! How do you set things like motor speed and such on it - does the INDI driver allow that...?

Also: the small and simple stepper motor - is that sufficient for heavier loads? I have only used Nema 17 motors so far.

Magnus

Yes, it connects directly to the Pi.

I already had a case with space for a HAT, since this is a fairly common thing it is easy to find cases with space for the hat. The connection points are also all in the same location so you can easily find universal cases that support it.

The Waveshare motor hat connects directly to the same Pi that runs kstars/EKOS. It can drive 2 stepper motors at the same time, and has multiple connection options either via a standard connector, terminal blocks, or headers.

The HAT takes 12v input via a barrel connector, so it is easy to power alongside cooled cameras or other 12v things like dew heaters. No more need to have a 3amp usbc input to power the Pi as the HAT will power it directly.

You don't need to have the Pi near the motor, it uses a 4 wire connection and so you can easily get a wire long enough to place the Pi somewhere other than on the scope, mine is about a foot away from the focuser, but it could be farther.

Kevin has made a driver that will handle everything you need. It lets you set the stepping speed, motor backlash, etc.

It was super easy to setup for me, just put the HAT on the Pi, plug the wire from the stepper motor into the terminal block and then set the delay in the driver. The motor is connected to the fine focus shaft on my focuser and has no issues with torque. I removed the fine focus knob and used a coupler to connect the shafts. I did design and 3d print a bracket to hold the motor and connect to my focuser, but you can pick up a commercial metal bracket that can be adapted.

You do need to build the driver as it is not included in the Stellarmate OS, but, it is a very simple procedure, and all of the steps are outlined on the driver's page. You do need to figure out how to wire the motor into the HAT, in my case the motor was not labeled the same as the HAT, which was the only annoyance.

Once the driver is setup, you just use it like any other driver in kstars/EKOS.

Hi Magnus,

the mini-stepper has an internal gearbox and has power enough if you will use a dual speed focusser (I use a Skywatcher 200PDS/1000 as well as a SVBONY 80/560mm APO).

www.thingiverse.com/thing:5160482
www.thingiverse.com/thing:5147337

I`m using the 5V version of the motor but there are also 12V versions. The stepper-driver boards let you select internal 5V or external 12V.There is some information about different versions of this stepper in the web, but cannot find them anymore.

The Arduino sketch starts smoothly and speeds up and slows down smoothly at the end. If you change the code on 1 line you can change the speed.
I patched an old version of the code, added a speed-switch and I'm able to select 2 different speeds as well as manual mode by pressing one of buttons.
But meanwhile I have seen that is not neccessary to have different speeds.However it is not possible to select different speeds in INDI.

The Moonlite protocol is used not allowing different speeds.If you have found the correct focus position it will not be neccessary to go long ways with focusser, especially with the Newton you need a close focus position when starting auto-focus.
Otherweise auto-focus will not work.

Cheers,
Hardy