I'm closer to building my timelapse rig and have already ordered all my hardware for the rail. The last bit I have left to order is all the electronics. I plan on using two or even three stepper motors to give me a linear motion with pan and tilt included. I have read that it's a terrible idea to connect your stepper motors directly to your Arduino board; is this true? I know I need the Arduino Uno R3 but am stuck knowing exactly what I need from this point on. Here is what I think I need. Please tell me otherwise if I am wrong or need more.
Arduino Uno R3
Adafruit Motor/Stepper/Servo Shield for Arduino kit
NEMA 14 Stepper Motor
Standard LCD 16x2 + extras - white on blue
I know I need wires and resistors and all that other jazz.. I'm not worried about that right now. I am concerned with the bigger purchases as far as boards and motors go.
I'm confused as to how all my wires will ultimately hook up. I know I need to solder wires to my board once I am finished testing on the breadboard; is this a blank shield I need or something to do that? If I use that how do I hook up the main Uno R3, motor shield, LCD screen, and then that blank shield all together into on unit and would a 9v battery even power all this or would it need to be stronger?
I'm sorry for all the obvious questions but I am still trying to learn as much as possible about the Arduino and circuitry. I am reading a few books right now so hopefully I will have a much better understanding in a few weeks.
Thank you for your help and I look forward to reading your responses!
Anyone have any advice for me; I'm still lost on this issue and can't find any decent tutorials online. They all show how to wire everything on a bread board but nothing post testing stage.
Okay, would it be better to use some kind of lithium battery that is rechargeable or something. If I end up going commercial with this product I want people to be able to take it out in the wild and use it for hours without having to worry about the batteries dying mid timelapse run. Suggestions?
Stepper motors draw continuos current even if not moving, unlike DC motors. This can be a problem in battery powered systems. The motors can be turned off between steps if holding torque is not needed. If you are using steppers rather than servos, carefully consider power management techniques.
Would it be possible for me to use servos for my system. From my understanding servo motors can't do 360 rotation. My system is going to be pulling a cart down a track via a rail so I need the pulley that is attached to the motor to be able to spin 360. I would like to have three motors on my system but I doubt I would be able to have enough power to run it with a lithium battery pack. I may just have to tell people to have it plugged in when using all three motors. This would be a huge buzz kill for my system since most people will be using it out doors and won't have a source of power but I don't know what my options could be since if people put the rail at an angle I will need the holding torque in between motion.
I'm still not exactly sure what to do with my board once I finished my circuit on the bread board. Do I have to get a blank circuit and solder every thing on to it or what?
I do not know the size of your system, power requirement, speed of motion, expected cost of parts, etc. There are fancier servos that have continuous rotation and position sensing. Steppers are sometimes tied to gears which can provide holding torque allowing better power management. Lithium batteries should work with proper design. How big a camera?. What distance of travel?
I'm still in the design stages of everything. The rail system will be ran via belt with a stepper motor (assuming that's the cheapest/best motor) on a 3 foot or 6 foot rail. I plan on using the Arduino Uno, a motor shield (if I need one), and then whatever other shield I would need to use to hold all of my wiring together in a permeant state. This last bit has me confused as to what I would need to use to hold all of the wiring together.
No, you don't want servos for long-term battery operation (as distinct from limited model aircraft flights and such) unless perhaps you arrange for them to have their power shut off most of the time - which means extra circuitry.
Steppers are just fine - given that you shut the controller off other than when you are actually performing a movement and that the controller itself consumes negligible standby current (so you need to research this) and that the gearing you apparently already have minimises "holding" torque demands and that a quarter step "slip" as the stepper is disabled will not affect matters.
Thank you!!! Finally an answer I was looking for. Yes, I am making something similar to that except I don't want it to be ran by a joystick. I actually just finished the rail system so all I have to do now is get my boards and program everything. Thank you again.
Paul__B:
No, you don't want servos for long-term battery operation (as distinct from limited model aircraft flights and such) unless perhaps you arrange for them to have their power shut off most of the time - which means extra circuitry.
Steppers are just fine - given that you shut the controller off other than when you are actually performing a movement and that the controller itself consumes negligible standby current (so you need to research this) and that the gearing you apparently already have minimises "holding" torque demands and that a quarter step "slip" as the stepper is disabled will not affect matters.
Thank you for helping me as well! I didn't fully understand everything you said but I will research it as well. My main concern is what will happen if someone tilts my rail at an angle and then I have a 5 pound camera and lens fighting gravity. I don't want to rail to somehow drop current and fall back to the bottom and destroy someones gear.
That Kessler actually uses a geared DC motor instead of a stepper which has a fairly high holding torque (not sure if it could hold 5lb's but it wouldn't get up speed). If you wanted to go with a stepper though for more acuracy you could always make a brake system so when not moving it won't go anywhere.
My main concern is what will happen if someone tilts my rail at an angle and then I have a 5 pound camera and lens fighting gravity. I don't want to rail to somehow drop current and fall back to the bottom and destroy someones gear.
This is a very strong argument for a gearbox. You may or may not use a stepper with it. The stepper alone would require battery draining holding torque. The Kessler mentioned is a servo system. It is using a DC motor, a gearbox and some sort of position sensing. That's a SERVO regardless of what they choose to call it.
The easy driver is $14 per one and the motor shield is only $19 so wouldn't it be better to go with the motor shield (assuming it's what I need to use)
You should be aware that stepper drivers such as EasyDriver provide considerable benefits including better torque, efficiency and smoothness of operation (less vibration).
What are your thoughts on using a threaded rod that runs through a nut that is attached to the plate that slides? The stepper motor would be connected to the rod and as the rod moves it would push the plate forward. I could greatly reduce the power to the motor in between motion and since it's a threaded rod I don't see the plate being able to slide back down the track unlike it would if it was attached with a belt and pulley system. Do you think this idea would help me solve my battery/holding torque issue?
What are your thoughts on using a threaded rod that runs through a nut that is attached to the plate that slides? The stepper motor would be connected to the rod and as the rod moves it would push the plate forward. I could greatly reduce the power to the motor in between motion and since it's a threaded rod I don't see the plate being able to slide back down the track unlike it would if it was attached with a belt and pulley system. Do you think this idea would help me solve my battery/holding torque issue?
Yes I would also use EasyDriver. Look up "micro-stepping". Choose the rod & bearings carefully for best results.
I'm hold in my hand exactly such a threaded rod-stepper mechanism at this moment, but it is much smaller.
I would also use EasyDriver. Look up "micro-stepping". Choose the rod & bearings carefully for best results.