Motors

Hey guys,

I am confused on where this topic should go so I am posting in this section. What are some strong motors whether they are stepper, servos or dc that can move roughly 50-75 pounds along and parallel to the shaft which the motor is driving? Where would be a good place to purchase them and their drivers? The idea is to have a bunch of drinks stacked up on each other approximately 2-3 of these (see picture below) on top of each other all on the same shaft. The power source will need to be plugged into a typical 120V outlet you find in a home or store. (The max current would typically be 15A from these outlets so that's what we're looking at)

We want to have the motor drive this shaft alone to test its limits but what ultimately we will do in the end is have gears with different gear ratios to lessen the torque.

These people have good stepping motors:- http://www.motioncontrolproducts.co.uk/product_info.php?cPath=4&products_id=6

Oops! This page appears broken.

I click on the site then directs me to the "oops.." page. Not sure if it matters that I live in the US or not.

Also another specification for any motor we're looking for is that it have high torque rather than high speed. We're not going to be ramping up the carousel to centrifuge anything.

I click on the site then directs me to the "oops.." page.

It doesn't do that for me, I have just checked it.

I am not sure how experienced you are with motors but 15A at mains voltage (all be it at wimpy U.S. mains voltage) is quite a lot of torque. The load you show is very small in comparison to what 15A at any voltage will give you. Also 15A is a great deal of current to be playing with if you don't know what you are doing.

The 15A and said voltage was just to give parameters to help me out. I am sure we will be using less than half of that but having suggestions of electric motors out of the 15A and 120v range is useless for us.

I thought maybe I couldn't see the site because I was in the U.S. I entered the main page of the site but I am not sure what you were trying to show me on that company's site.

I'll update my profile later, I gotta go to class right now!

I thought maybe I couldn't see the site because I was in the U.S.

Here are some good sources for (surplus) motors in the US:

http://www.allelectronics.com/ http://www.herbach.com/ http://www.alltronics.com/ http://www.goldmine-elec.com/ http://www.sciplus.com/

This is just the tip of iceberg; if you want to be really successful in sourcing parts in this hobby we call electronics, you need to collect these links, organize them, and in some case "internalize" them. You need to collect links that others post, and forward them on yourself to others who may or may not know them. Being in the US has the great privilege of having access to some of the best surplus electronics the world has to offer.

Also - if you live in or near any large city, chances are there's a surplus or junk dealer in electronics in that city (especially if you have any large hardware tech companies like HP, Honeywell, IBM, Intel, Motorola, etc nearby - or research centers, too - don't forget those!).

Your best bet for finding a lot of this stuff is to ask people you know who are into electronics that live in your area; if you have any voc-tech schools or community colleges (or the engineering department of a university) - ask there. Look in the yellow pages under "electronics" and "surplus". Look online - Google is your friend. Note that some may not be places open to the public - or only trade in large quantites.

Finally - for some things (like motors, for instance) - Pick-Ur-Part auto salvage places and/or salvage yards can be great places to find stuff, if you're willing to haul around tools, pay an entry fee, and get seriously dirty...

:)

You need to be more specific about what you're doing.

How far are you moving this "stack o' racks"?

How fast do you need to move it?

Are you moving it horizontally? Or raising/lowering it for easy access to the bottles?

If you've got all day, you could use a little 9V Lego motor, gear the bleep out of it, and slo-o-o-wly winch or drag the load to where you want it.

But my guess is that you want to move it a lot faster, so you'll need a heftier motor and mechanism.

The stack of racks wont be moving anywhere, it'll be stationary but it will be rotating about its shaft.

The speed should be at a comfortable pace that doesn't appear too slow or too fast. Our idea of too fast is if the bottles look like they are on the verge of flying off possibly hurting someone if they get too close. Not so slow either. Basically a speed that is similar to as if the user was manually turning the carousel by hand browsing at the different liquids. It's all ideas right now for that part. We're concentrating on designing and building it.

There will be a scaffold-like sleeve that will hold the glass cup in place and move along the axis perpendicular to the surface of the ground stopping at the desired bottle at each level of the mixed drink ingredient selected. See the image below to see what I'm describing as a kind of scaffold that will hold the glass cup. The glass cup will have an "arm" extend out of the scaffold so that it is directly below the center valve (the bottle on the carousel which is tangent to the scaffold) then retracts so that it can move up or down from each location.

Did I mention that the carousels will be custom built so that they are stacked up on top of each other sharing one single shaft? So one electric motor will be working to turn all the carousels. We were possibly thinking of a way to add ball bearings to it in reducing friction and torsion stress. Another motor to extend and retract the "arm" which we think will be on the scaffold. So far three motors for our idea. One to rotate the carousel, one to move the scaffold vertically away and towards the ground, and one to control the "arm".

@Crosh, thanks for the links. I'm a mechanical engineer major student but I definitely love the electronic side (at least to an extent before I start getting lost in its abstractness). They need a electro-mechanical engineer major at my school.

*I put "arm" in quotes because it's not really going to be a robot arm but that's our terminology until we can figure out what it will look like. We're putting together a solidworks design and having our computer engineer helping with finding a microcontroller and programing aspect which should help tremendously. I'm the one who loves motors, however.

Bump for any suggestions

If you use good mechanical design with bearings and such, then a large motor may not be needed. Since you are looking for an AC motor, you might look at an inexpensive electric can opener for a strong ~slow turning AC motor.

how much space you have, budget, timetable, resources, experience, etc. etc

  • space is assumed to be roughly the same parameters you see a standard coca-cola United State's soda bottle vendor (the one that sells soda for US $1.00+)
  • 12k+ budget
  • have until mid April to complete this which I know is little time
  • The club inherited some dc motors from when former members made things with the funds
  • Machine shop (mill, lathe - 6 months), weld experience, basic programming skills, basic electric circuitry skills
  • Access to tools, machine shop, welding tools, etc.
  • Intermediate/Advanced skill level of Solidworks/AutoCad
  • 6+ club members on this project

I'm not going to list everything about our project because some of it is proprietary in the sense that someone on these forums may be going to the convention we are going to and take our idea.

Me, being more of the coordinator and representative of the club, I am more reserved so I keep throwing my pitch into the pot of ideas telling them to find used parts and don't necessarily go for the largest things.

Nema 34 2550 oz/in Stepper Motor Model #RS34-2550 Source: http://www.homeshopcnc.com/RSstepperMotors2.html That's one of the largest step motors I have found and one of the members is pushing towards this. Not only is it pricey but it seems overly powerful for our application.

If you use good mechanical design with bearings and such, then a large motor may not be needed.

We actually came up with that idea of having a good set of ball bearings that the carousel will rotate about and gear/chain the carousel to a lower set of gears to reduce torque and moment.

As for the scaffold, it is supposedly going to be controlled by two all-threads that are both connected to one step motor through gear chains as well. This was an idea one of our group members came up with and getting the precise measurements for that will be a doozy.

Not only is it pricey but it seems overly powerful for our application.

That 2550 oz/in rating is 13.25 lb/ft. Nothing in your original picture appears to be located a foot out from the center shaft, not does anything appear to need that much torque to rotate it. You should be able to get a rough idea of the torque needed from how you rotate it by hand. How far out from the center do you grab something, and how many fingers do you use. If it requires a handle on a 1 foot arm, and you can feel the weight in your shoulder, that motor is appropriate. If it takes one finger pushing on a 4" arm, that motor is overkill.

It seems your "club" is making the critical decisions in the design of your project (which you will keep secret), so what help do you need with the arduino?

Zoomkat,

The arduino part, we were thinking of buying the Arduino Mega 2560 (Source: http://arduino.cc/en/Main/ArduinoBoardMega2560), two to three of them. Again, I am more judgmental and conservative so I think we only need one or two of them at most. The microcontroller will control LEDs for cosmetics that will most likely outline the frame and outer walls of the structure. We were also thinking of either a touch LCD screen or just a color screen with keypad. The microcontroller must also control all the motors (estimate of 4 bi polar stepper motors which most likely have 8 leads each). Lastly it will play music or have sound effects.

My question is, is it possible to connect/network three Arduino UNO's with one being the motherboard that controls and send signals to the other two Arduino UNO's? If so, does networking three Arduino microcontrollers also increase the memory? Also, is there someway that instead of the majority of the I/O pins be taken by LEDs that there is some external hardware that we can hook up and work in cooperation with the Arduino microcontroller that can take the brunt force of flashing and turning on and off LEDs in patterns and sequences? We have one computer engineer major in our club to help with the programming but he has a lot of his time invested in other things so he is not able to do all the research for the microcontroller and functionalities of it. Me, being a mechanical engineer major, I know that I am a new blood when it comes to micro controllers so bear with me and my naiveness on the matter. I am willing to understand and learn. I also know some of this is found on the Arduino site but I am busy researching motors and solenoid valves right now for the project and also writing up quote requests.

Pauls, Thanks. I will look into other motors and let the club know.

My question is, is it possible to connect/network three Arduino UNO's with one being the motherboard that controls and send signals to the other two Arduino UNO's?

I would think so. I'd connect the master uno serial tx to the slave uno's serial rx. Start the messages from the master with a specific slave identifying character, and then have the slaves look at the starting character of messages sent to determine if the message for them.

Also, is there someway that instead of the majority of the I/O pins be taken by LEDs that there is some external hardware that we can hook up and work in cooperation with the Arduino microcontroller that can take the brunt force of flashing and turning on and off LEDs in patterns and sequences?

Others probably know more about the LED posibilities. Betabrite types of signs might be a premade option.

estimate of 4 bi polar stepper motors which most likely have 8 leads each

Why 8 leads? A bipolar stepper motor needs only 4 leads. Those would be connected to a motor controller, not directly to the Arduino. A stepper motor, especially that monster you showed, than the Arduino even has dreams of providing.

Two wires then run to the Arduino - one to define direction, and one to make the motor take a step.

Lastly it will play music or have sound effects.

No, it won't. More likely, you'll need a mp3 player (http://www.adafruit.com/index.php?main_page=product_info&cPath=17_21&products_id=94 for instance) that can hold audio files, and play them on demand.

If so, does networking three Arduino microcontrollers also increase the memory?

Individually, yes. But "memory" on one can not be used by another.

Zoomkat, thanks I’ll look into Betabrite. I think another option I found is Lightorama.com. Is there a place either on these forums or the Arduino site that describes how to send the message to define which is the master and slave controller (the program/coding)? If so, where?

PaulS,
Err sorry, I meant the motors we have will have 8 wire leads giving it the option of either being a parallel or series (we’ll most likely set it up to be series) bi-polar step motor. The signal to the motor driver will either be 2 or 4 leads depending on if we’re only going to allow the step motor to rotate in two directions or one. I will also check into that mp3 player.

Two wires then run to the Arduino - one to define direction, and one to make the motor take a step.

I thought Arduino defines those with the library but would require 4 wires like what is needed on a quadruple half-h bridge.
i.e. High, LOW, LOW, LOW
LOW, HIGH, LOW, LOW
LOW, LOW, HIGH, LOW
etc. except the step motor library does all that so that I would not have to individually tell each I/O pin when to go HIGH or LOW for the motor driver.

Can you elaborate on what you were saying? Possibly schematic or pictures?

Another question for anybody reading this thread, some solenoid valves have a third wire running out of it, what is the third one for and how would I wire that up to the controller with three wires? I am assuming one is for the power, one for the ground and the last one to control position of the solenoid coil?

Can you elaborate on what you were saying? Possibly schematic or pictures?

This stepper motor driver http://www.sparkfun.com/products/9402 has 4 connections for the stepper motor, and two for the microcontroller (well, 3 if you include ground, and you need to) for direction (HIGH goes one way, LOW goes the other) and stepping (each LOW to HIGH change causes a single step).

for direction (HIGH goes one way, LOW goes the other) and stepping (each LOW to HIGH change causes a single step).

PaulS, my next question is, can you do that with the Arduino stepper motor library? Can the stepping be from HIGH to LOW as well or just LOW to HIGH? What does the program/coding look like to send the signals to the EasyDriver to perform those functions of the bi-polar step motor?

Here is my stab at what the coding would look like, of what you were saying:

int direction=2;
int steps=3;

void setup(){
pinMode(direction,OUTPUT);
pinMode(steps,OUTPUT);
}
void loop(){
digitalWrite(direction, HIGH); //defined one direction
for(int i = 0; i<=400; i++){// will cause the motor to step 400 times
digitalWrite(steps, LOW);
delayMicroseconds(10);//place delayMicroseconds for speed is my guess
digitalWrite(steps,HIGH);//one step completed
delayMicroseconds(90);
}
digitalWrite(direction, LOW);//opposite direction now
for (int i = 0; i<= 200; i++){// 200 steps
digitalWrite(steps, LOW);//different speed
delayMicroseconds(80);
digitalWrite(steps, HIGH);
delayMicroseconds(20);//delay microseconds must always add up to 100 microseconds?
}
}

can you do that with the Arduino stepper motor library?

Yes. The code you posted shows how to do it without the Stepper library, although I had it backwards. The motor steps when the pin goes HIGH.