April 30, 2019 at 10:12 pm #98825
Well, thanks a pant load (once again) guys! I’m super stoked that this project is DONE!
If you don’t quite get what’s going on here, the start of the test runs all the steppers back to their start position…..technically these guys are supposed to be hooked up to camera sliders, pan and tilt heads, focus rings, objects that are to move on stage etc. When the test runs, the steppers jog to position #1 for the start frame, advance to the next spot for the second frame and so on and so on frame by frame as you animate. The steppers advance after each shot is taken but those shots are controlled by the animator. Once the puppets/props etc have been moved for the next shot you hit a capture button, the shot is taken and the steppers advance to the right spot for the next shot.
Accurate, programmable, repeatable and fine tuneable. With this set up I’ll be able to do complex camera moves and verify the shots will work and frame up properly before committing to the animation of the subjects on stage. Can’t wait to get this stuff hooked up to some gear!
FWIW – Stop motion animation is solidly placed on the “hobby” spectrum in my life and definitely not top priority. I’m still gathering and amassing gear for the “studio” which I have been doing slowly over the past six years or so. This $100 project has saved me THOUSANDS on commercial motion control gear. Literally. It’s a big milestone in my studio preparations. And one of the last big milestones….it may be time to start animating quite soon. Thanks again for the off-topic assistance! Beers all around!April 30, 2019 at 10:15 pm #98826
One other thing….holy heat generator Batman! The heat coming off that Arduino/Shield is ridiculous. I set my pots to ~750mV (steppers rated at 1.7 Amps). Should I hook up a cooling fan or should I dial down the pots a bit?May 1, 2019 at 1:27 am #98836
Nice! Open hardware and open source software For The Win!
You should post your modified file back to the source to hopefully give the next Kelly that little leg up.
Personally, I would turn down the current. You’ll see a big reduction in heat if you do and you’re not milling aluminum, you’re moving a camera. It depends on the mechanics though. If you’ve got poor mechanical advantage you might need the torque.
Have you seen this? https://www.v1engineering.com/forum/topic/mostly-printed-camslider/May 1, 2019 at 1:31 am #98837
Your 12V 3A power supply is also technically being over worked. 750mV is 1.5Ax4 is 6A at 12V.May 1, 2019 at 7:16 am #98876
Thanks. I’ll turn them down to 500mV. I’m not sure how often I’ll ever run four steppers at once but I’ll be sure to keep an eye on the power supply. What would be the point of failure? Would it kill the power brick (which is fine) or could it fry the Arduino/Shield?May 1, 2019 at 3:40 pm #98957
The point of failure is probably the PSU running at 9V instead of 12V or something. Eventually, something might get so hot as to pop (in the PSU).
Even if you’re not moving all the motors, if you have them enabled, they are each consuming 1A at 500mV. The current is on when they are stopped just to hold them in place.May 1, 2019 at 5:05 pm #98972
Your 12V 3A power supply is also technically being over worked. 750mV is 1.5Ax4 is 6A at 12V.
As I understand it, the output current to the motors doesn’t translate directly to input current from the PSU. The motor controller acts somewhat like a buck converter, transforming higher voltage lower current input into lower voltage higher current output, using the inductance of the motor itself.
It’s hard to predict the input current, especially since it changes once things are moving. Best to just measure it. But don’t be surprised if it’s much less than the current through the motors.May 1, 2019 at 6:36 pm #98987
So you know what the overarching wonder is that’s rolling around in my pea brain over all of this? At what point does the student become the teacher for me? I mean, how can I move from “following instructions” to paving the way? I fell down a rabbit hole late last night called “Otto Robot” and am now keen on playing with some nanos. These little computers or whatever the “proper” term is for them are so versatile it’s almost mind boggling. But without someone leading the way for me I’d just have a pile of boards around and no clue what to do with them.
The Moco project got me thinking – what if I wanted to build a stepper driven piece of home decor that required the stepper to give me 27 full rotations over a 12 hour period and then reverse over the next twelve hours? Where would I start looking to learn how to make that happen?May 1, 2019 at 6:48 pm #98989
“Otto Robot” and am now keen on playing with some nanos. These little computers or whatever the “proper” term is for them are so versatile it’s almost mind boggling. But without someone leading the way for me I’d just have a pile of boards around and no clue what to do with them.
I have a few otto kits here for any of my friends older kids that show interest in my nerd stuff. I used a few nano’s in my college senior project, in the PID, and I have 50 or so on hand. All the arduino’s are crazy versatile, robust, and well documented. Get a kit with switches, buttons, screens and sensors and just play around. Pretty mind expanding when you start to get it. Heffe taught me about interrupts, leveled me up a bit…
what if I wanted to build a stepper driven piece of home decor that required the stepper to give me 27 full rotations over a 12 hour period and then reverse over the next twelve hours? Where would I start looking to learn how to make that happen?
I would start with two things separately…time how to use it on a Arduino, and How to drive a stepper with a nano. Then add them together.May 1, 2019 at 7:03 pm #98990
what if I wanted to build a stepper driven piece of home decor that required the stepper to give me 27 full rotations over a 12 hour period and then reverse over the next twelve hours?
27 rotations and 200 steps per full step and 16 steps per full step = 86,400 steps per day.
24 hours, 60 minutes, 60 second = … what? 86,400!
Just run the blink sketch! Oh wait, you want just 12 hours.
If you’re ok with slop, you can use a lot of basic techniques to count. If it needs to be precise, because it’s a clock, then you’ll need an external source for a clock. Either ntp and wifi, a real time clock with a battery, or a GPS receiver.
As for becoming a teacher, it’s not really binary like that. You could help Kelly from just a few months ago and you’ll get more capable with each project. There is an enormous amount to learn though, so don’t be surprised if you are still following directions a few years from now. Personally, I have my engineering degrees, and a lot of on the job experience, and I’ve watched a ton of videos. I used to go through all the adafruit and sparkfun tutorials.May 2, 2019 at 4:31 am #99014
I LOVE these Arduinos! I’ve learned SO much from them! …so many projects… Some of my favourites have been
controller for my reef tank –monitored and controlled temperature(relay board and temp probe), monitored PH(ph probe), ATO (automatic top off, float switches and peristaltic pumps), dosing with peristaltic pumps, controlled via webpage run on arduino, tracking and uploading all information to Sparkfun data server (I’d use Grafana now adays)
simple boat autopilot using heavy duty hobby servo and compass to point a trolling motor
MINIMOSD — on screen display for the video feed from my old drone. it overlayed data from the flight controller (altitude/airpseed/battery, etc) much like the new DJI drones do, this was way before that though.
SatNOGS Open source satellite tracker — Azimuth elevation tracker for antenna to track objects across the sky as they travel through space to ensure the strongest signal possible. This was the project that introduced me to 3d printing and led me to the MPCNC eventually. I connect it to software on the computer called Gpredict which lets me track basically anything.
MPCNC — obviously! 😛
I think it’s pretty awesome that a huge chunk of the 3D printer market is powered by them as well, makes things so much more approachable!May 3, 2019 at 10:20 am #99148
Alright then. I just ordered a cheap super starter kit. Looking forward to it! As a bonus it looks to contain a lot of the bits I’ll need for one of our family of Ottos. It’ll be neat to see how the girls (10 and 6 1/2) take to robotics and electronics. Might be too soon for the young one to process what’s going on but I bet the 10 year old will grasp it. At least on the surface.
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