IT'S ALIVE! Barn door tracker gets electricity.

A video diary of the digitization of my barn door tracker. This shows how added a threaded stepper motor to the rig for automatic tracking. It also shows DIY doesn't always go as planned.
Arduino: prourls.co/cR7B
Motor Driver: prourls.co/040V
Stepper Motor: www.sparkfun.c...
Arduino code: gist.github.co...
3D models:
Motor mount plate: www.thingivers...
Threaded rod sheath: www.thingivers...
Intro by the very talented Martin Macpherson: martinmacpherso...
Music:
Almost Original (Instrumental) by Joakim Karud / joakimkarud
Music provided by Audio Library • Almost Original (Instr...

[@leonaka6539]

great video. I like that you showed the issues while building it. Very real life!

[@BenjaminEagan]

Thanks! It never goes as smoothly as you think, so I try to capture some of the pain as well.

[@johnkemas7344]

I see your Arduino code (I believe )takes into account tangential error from using a fixed drive rod as opposed to a curved rod. Easy to do with a stepper motor! I build mine with a pivot on the top drive rod to base mount and a pivot on the bottom mount also. Removes much but not all of the tangential error. Nicely done! I have isolated the drive stepper from the rest of the rig with soft shock motor mounts and a shock shaft coupler to help reduce vibration. Seems to work well.

[@mesample1705]

The stepper will vibrate a bit which will look like a focus issue in frame. Also attaching the stepper to the bottom board and adding mass will reduce this symptom. I believe someone comment to your previous video taking 30 second frames, registering stacking those in software such as DeepSkyStacker will eliminate some of the remaining star trail due to polar misalignment. Your next step with be to add dithering which reduces color mottle. Great ideas you put into your design. Thanks for sharing.

[@BenjaminEagan]

Thanks for the advice Michael! Good suggestion...It would be cool to sync the shutter mechanism with the stepper so the motion doesn't add blur. Now I will Google dithering and mottle 😀

[@mesample1705]

@@BenjaminEagan , I encourage you to read Dave Trott's web articles. He includes formulas and a graph comparing theoretical tracking error of each design. davetrott.com/inventions/double-arm-barn-door-drive/ There is another website which shows effect of micro-stepping on a stepper's holding tongue.

[@cpirius]

FYI, don't unplug the stepper motor while the motor driver board is powered, it can kill the motor driver chip.

[@clonkex]

Came here to say this. I was horrified when he just unplugged it!

[@renderuthis]

I could not endure to watch the video but you need to rewrite what you said. what did he do with it plunged in? You know it has to be on to work.

[@in-finite5483]

Suggestion= The easy way is to flip the model and add an inflated balloon between the board and a nozzle . Calibrate the releasing air/water to desired rate. What do you think?

[@BenjaminEagan]

It’s an interesting idea, but the rate of deflation/draining wouldn’t be constant. So I doubt it’s that simple - but I’d love if you prove me wrong.

[@amoghdeshpande505]

Which motor driver is used here? The link isn't working

[@melongeed]

Loved the camera on the chair, this is actually really cool good guide

[@youngstone99]

What driver are u using could u share the code aswell?

[@Thomate1375]

Yeah but aren't there some cheap star trackers for that price that could be at least as good qs this diy tracker?

[@BenjaminEagan]

Not that I know of, at the time of making this the cheapest tracker started at around $700. If cheaper ones have come out since I might have to pick one up myself.

[@jamesray9009]

well they have some in the 500$ range now but here it is 3 years later and I'm looking at ways to build one.. I have 3d printers and tons of parts Im thinking about using aluminum extrusion.. I would really like to know if you had continued with it

[@johnbig-bootay2825]

Hey Ben. Did you ever get it out to the field? I'm using someone else's code with mine, but it still comes up with star trails if I stack a bunch of 25-second exposures. I'll give your code a try and report back.

[@BenjaminEagan]

It worked with poor light conditions but then the rod got stripped and started to skip. So I'd like to redesign with a regular stepper just for robustness

[@johnbig-bootay2825]

This is one that I've built based on a design I found on Thingiverse. I'm probably going to hold on for a new moon then head West to a dark area to do more testing. instagram.com/p/BldSzkGFpiw/?taken-by=aussiemandias