building a automated focus rail

xmachiavellianx · Post by **xmachiavellianx** » Sun Sep 03, 2017 11:37 am

Any suggestions for either building one or using a stackshot at about 20x and below?

-Thank you

Deanimator · Post by **Deanimator** » Sun Sep 03, 2017 6:56 pm

Some people apparently use old flatbed scanners, something far beyond my talents.

ray_parkhurst · Post by **ray_parkhurst** » Sun Sep 03, 2017 8:09 pm

When you're starting out, it's much easier to just buy a stackshot, mjkzz, or WeMacro rail with controller and software. Building your own system, with ready-made rail, is possible. Building your own rail is quite a bit more involved.

The biggest obstacle is the stepper and how to control it. Most likely you will end up using a stackshot, mjkzz, or WeMacro controller to run the stepper, so starting with one of their rails seems natural.

Going one step further, better rails are available fairly readily. THK and Misumi make excellent rails that can be integrated with stackshot, mjkzz, or WeMacro steppers and controllers, and can give you higher resolution stepping. This is fairly involved and many rail types exist. It's easy to buy the wrong model, and will take some work to integrate into a working system, but ultimately will give a superior product.

elf · Post by **elf** » Mon Sep 04, 2017 12:42 am

It all depends on your skill level as a designer, machinist, and software developer

The first step is to write out a full list of requirements. Here's a few hardware and software items to start with:

Budget.
Minimum repeatable step size (with tolerances).
Backlash tolerance.
Maximum weight.
Studio or field setup with or without handholding capabilities.
Horizontal or vertical or both.
Vibration dampening.
Power requirements. Battery or mains.
Lighting/multiple flash attachment points.
Flash or natural light.
Diffusion attachment points.
Subject stage with XYZ movements.
Bellows capabilities. AFAIK, no commercial rails have this.
Panorama capabilities. AFAIK, no commercial rails have this.
Video capabilities.
Interface with Zerene Stacker, Helicon Focus, or other tethering options.
Image capture rate.
Touchscreen, Smart phone, Android or iPhone, and/or computer control.
Did I mention Budget.

If you can program in C++, it's actually pretty easy to write the software to control the rail. If you use an Arduino, there are libraries for controlling stepper motors and lots of help on their forums. I'm currently using a Teensy 3.2 which is a 32 bit Arduino derivative.