Elevator project(noob alert)

What stepper motor would be ideal to lift Approximately 10lbs up and down an elevator, I want it to be about 4-5ft high. I'm using a arduino UNO... I'm a noob to Arduino:( what else would I need to Operate the stepper motor? Shields? Oh and I want to use a IR sensor to make it stop at 3 points...

This read will help...
https://learn.sparkfun.com/tutorials/motors-and-selecting-the-right-one

I am not sold on using a stepper... I think a DC reversible motor with an appropriate gear box is a better fit.

Ray

Mr. B has a point. If you have an SUV with a WINCH (be careful not to call it a WENCH or you'll get lots of wise cracks from the "mates" in the UK) it is a DC motor with a gearbox. A hummer can WINCH itself UP straight up cliff so they obviously are very
strong. I think an automobile starter motor with a gearbox would be perfect , driven with a car battery and probably an automotive grade IGBT. It might be a bit of a challenge to find the gearbox though. If I had to do it I would probably go with stepper motors with drive belts and stacked pulleys. (slide two pulleys on a shaft, one large one small) . The stepper motor has a small pulley and
turns a large pulley that also has a small pulley. For a 10 to 1 ratio, the large pulley is 10 times the diameter of the small pulley. It
takes one revolution of the large pulley for one revolution of the small pulley. If the large pulley is 20 times the diameter of the stepper motor drive pulley then it takes 20 revolutions of the stepper motor to get one revolution of the large pulley which gets you 10 revolutions of the small pulley on the same shaft as the large pulley. Say that ten times quickly...

raschemmel:
I think an automobile starter motor with a gearbox would be perfect , driven with a car battery and probably an automotive grade IGBT.

Very cool. which got me thinking...

Two levels down in scale from the starter motor is windshield wiper motor, gearbox included in the assembly. Just as an example, (this video he doesn't mention -exactly- that he has,) but at 2:45 I'd bet it it can wind the snot out of a 1/16-1/8" stainless braided wire. Windshield wiper motor both servo and speed controller - YouTube (Snot not included. :P)

One level down from that is the power window motor.

All of these items are available for CHEAP at the local auto scrapyard, or NIB from ebay.

As to which one, one factor that wasn't mentioned was how -fast- that 10# needs to go up 5'.

Cool ! That is very useful information. There must be a thousand uses for that assembly ! Now all you need is the service manual schematic to get the wiring . Let' see now , which one of these schematic is it anyway?
http://www.bing.com/images/search?q=automobile+power+window+module+wiring&id=E51BBFFCCBB76562D022997CE5F800EFE6F5232F&FORM=IQFRBA

raschemmel:
Cool ! That is very useful information. There must be a thousand uses for that assembly ! Now all you need is the service manual schematic to get the wiring . Let' see now , which one of these schematic is it anyway?

(Always start with the simplest.) This one... http://wright-here.net/images/rx7/Mods/PWindow_wiring.gif

That's a 'mechanical' (relay operated) representation of the circuit you need. It uses two switches and two relays to manage the polarity (direction) of the motor.

In your case, the switches, you send the output of the Arduino to small FET transistors, which drive the relay.

RATS, that pic doesn't show the interior circuit of each relay, but you should be able to get the idea - one relay connects the polarity in one direction, +/-, and the other switch connects the polarity in the other direction, -/+.

WATCH OUT (in software) that you NEVER turn on both relays at the same time. The switch is typically a rocker, which can't connect in both directions at the same time.

If you want to do the same thing in 'pure solid state' look up H-bridge and SSR solid state relay.

Relays might be totally suitable enough for your needs because you don't need anything particularly high speed.

BTW the biggest advantage of a geared system is that on power failure (oops a wire disconnects from a battery or a plug is kicked out from a wall outlet) a 'plain' motor would freewheel and drop 10# from 5' high. :astonished:

This is going to sound stupid but I need to know, besides the Arduino UNO Board, what else am I going to need to power and control the windshield motor(I have an idea of what but not sure)? The windshield motor was a great idea,thanks... I'm learning so much form this arduino forum

Braindamage:
This is going to sound stupid but I need to know, besides the Arduino UNO Board, what else am I going to need to power and control the windshield motor(I have an idea of what but not sure)?

Rats I forgot to post the URL of a nice vid. But I left it out mostly because he used a very expensive motor controller board. The reason it's expensive is that it has tons of features that you won't need, or can probably be programmed in Arduino anyway. Windshield wiper motor both servo and speed controller - YouTube http://devicecraft.com

Here's a design that I like better because it's simpler and still totally functional. Scroll down to the -last- schematic. It uses optoisolators which is a plus for safety. Mechanical Engineering | College of Science and Engineering

The TIP102 should be replaced with FET because they're much more efficient. Either require heatsink anyway.

Safety, reminds me, add a fuse to the + side of the power source.

Also as regards safety I tend to allow for lots of headroom because I HATE electrical fires. LOL!! Wiper motor runs typically at 2A, but might draw 3 or 4 under load/jam. FETs often run 5A. Relays should be the same or a little better.

That schematic doesn't show switches but you'll need them for manual operation. You could add mechanical switches that bypass the transistors, and/or add pushbuttons to input to the Arduino to control the two output pins.

You mentioned IR sensors. They're nice because they're invisible, but unless I -need- invisible or the light is annoying I prefer LED/photoresistor because they're much cheaper.

Again safety. A strong geared motor can do a LOT of damage if it gets out of control. In this case you have mechanical structures and cables and such. An out of control motor/cable can rip structures apart, detach fingers and such. Do all testing first with LEDs rather than the motor connected, until you're -sure- the motor will behave properly when the whole mechanical system starts running. I think I'd add a BRS (Big Red Switch) -panic- button right in the front of the whole structure, connected to the + side of the battery, that IF something goes wrong you just whap on it to kill the power.

The windshield motor was a great idea,thanks... I'm learning so much form this arduino forum

Be very careful what you wish for. This can get very addictive. :astonished: :grin:

Thanks! That's alot of help... If I lose a finger you'll be the first to find out, just kidding.

You saw in the video that the pcb had the drivers on it and all he did was supply power and signal.(+12V obviously)

raschemmel:
You saw in the video that the pcb had the drivers on it and all he did was supply power and signal.(+12V obviously)

Sure and if you want one you also need to supply $200. LOL! I'm sure it has some hobby potential, but, it was designed around that -one- particular motor assembly. (Which happened to not be mentioned in the vid or the web page.) As was mentioned in the list of potential uses, if I'm a solar panel manufacturer or installer and I need a positioner, I'm not gonna lock my design into an automotive spare part that I may not be able to get again in 3 months. And I'm not gonna scrounge the auto junkyards for them either, because if my $2000 solar panel customer finds out what's going into his system he'll have a cow.

So it’s not a good idea to use a windshield motor? I was planning on heading to my local junk yard tomorrow. I’m completely new to all of this, The simpler/Inexpensive the better.

I was planning on heading to my local junk yard tomorrow.

It's probably not a good idea to wire it up if your brain damaged XD (sorry, couldn't resist)

What are the pro's and con's on why I should or shouldn't do so. It seems simple. Braindamage was my NN in HS

So far the only con is the cost, but that could easily be dismissed if you can talk a junkyard into selling you one cheap. The next step would be finding the wiring schematic for it. I would thing it would be easier to get documentation for something newer. I have a friend who says there's automotive DIY forums where you can find anything about anything. There are a few things we can almost take for granted and one of them is the fuse for that module is located under the hood so you should definitely find out the fuse rating and buy a fuseholder or use an inline 3AG FUSE /fuseholder of the same rating and wire that in series with the power. There has to be a control signal coming from the window rocker switch so maybe you should get a rocker switch for initial bench testing of the unit. You will need good power source and a car battery is the best choice but since it is small load you might want to look into a motor scooter or motorcycle battery. If you know any mechanics who would be willing to help you they would be able to
give you some useful tips. They would probably know how to get the wiring diagram.

How fast does the elevator need to move? A smaller geared motor could probably be used to move the elevator car at slower speeds. I think real elevators are often counter weighted to take some load off of the drive motor.

You got me thinking about the wiper motor... Would a 12v worm-gear motor be a good Substitute for the wiper motor? Keep in mind I want to use it for a elevator project. I want to be able to control the speed and direction of it, would I need other part besides the motor to control the speed/direction of it?

Here's a link of the motor:
http://www.amazon.com/gp/aw/d/B00F18HUYK/ref=mp_s_a_1_6?qid=1397851935&sr=8-6&pi=AC_SX110_SY165_QL70

I want it to be able to lift 5-10lbs up 3-4 feet. I don't want the speed to be too slow or too fast...

Braindamage:
You got me thinking about the wiper motor... Would a 12v worm-gear motor be a good Substitute for the wiper motor?

Sure, because they're almost synonyms. The wiper motor has the biggest difference of a bracket to mount it to a particular car firewall. Different models might have back/forth and speed control circuitry.

Keep in mind I want to use it for a elevator project. I want to be able to control the speed and direction of it, would I need other part besides the motor to control the speed/direction of it?

Asked and answered...

Direction is controlled by H-bridge, either solid state or relays.

Speed is controlled by PWM.

Relay control still require transistors for PWM speed control because relays are strictly on/off not variable.

http://www.amazon.com/gp/aw/d/B00F18HUYK/ref=mp_s_a_1_6?qid=1397851935&sr=8-6&pi=AC_SX110_SY165_QL70

There's a pic there that's probably some sort of data sheet but it's so small as to be illegible. I found the same thing with a legible description at Worm gear motor DC geared motor GW31ZY 12V 8rpm | eBay There are a bunch of different related widgets with various ranges of capability. A 'wiper motor,' you deal with what you have. That list, this is where the 'engineering' part comes in - picking the right one to fit the requirements of a given task. :slight_smile:

Speed and power are related to the shaft or wheel that the cable wraps around. You'll need to do the arithmetic and geometry to relate the RPM / shaft-wheel radius / torque / lift speed. Wrap the cable directly around the shaft, and you can lift a tremendous load very slowly. Add a larger wheel diameter to wrap the cable and you can lift a lighter load much faster. That's your basic speed control. It sets your max load and highest speed. After that you can adjust acceleration and deceleration and finer speed adjustments via PWM. You could write a spreadsheet to plug numbers into to find out what the relationships of the variables are. Or you -might- be able to find something via google already written, maybe an online java calculator.

Braindamage:
I don't want the speed to be too slow or too fast...

That's how management asks for things. You have NO idea how DIFFICULT they are to make happy.

Engineer: Here ya go, Max, try it and let me know what you think.

Max: I set it to slow speed, started it, went out for lunch, and when I can back it was about halfway done, so yeah, I think that's a little too slow.

Next day... Engineer: OK here ya go, Max, I tweaked it a bit, lemme know how it goes.

Max: I set it to high speed. Unfortunately it ripped a hole in the space-time continuum and sent me backward in time by about half an hour. I was trying to think of what to do, a half hour passed to when I started it the first time, 'I' (or more exactly my previous future self) started it again, and I got pushed back an -hour-. An hour later, well, I guess you see where this is going. [sigh] By the time it was two weeks ago when this project started I figured out that I should leave a note on your desk that you should watch out for this little 'problem.' I'm guessing that you haven't figured it out yet, because it's now 1939 and I'm off to the World's Fair for the afternoon. Hope to hear from you late-sooner, though I do admit I'm looking forwardback to meeting Ben Franklin and also checking out how that whole evolution thing got started.