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JDAWGBAILZ
02-19-2014, 11:49 PM
I'm trying to create a motorized roller that can go both directions so I can unroll and roll back up a flag and I want to build a second one for a "curtain" made from a red bed sheet. The flag one will be 5 feet long and the curtain one will be 10 feet long. They have to be able roll 2 different ways so this is where I'm stuck as to what motor to use and what motor will have enough power to roll PVC pipe. Help please!!!


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Roterhead
02-20-2014, 03:16 AM
Gonna need a lot of torque in the motor. I'd probably start with a windshield wiper motor and pulleys... Then would look for bearings on eBay that would fit inside the PVC tube...

toozie21
02-20-2014, 10:08 AM
I agree with rotorhead. I used a similar concept to pull my animated nativity star up/down (I don't have a write-up on my page for it yet, but here is a video http://www.youtube.com/watch?v=3wAtDC-7jIE)

I use a wiper motor and switched directions using relays to reverse the voltage. I used reed switches and magnets to detect when I got to the end of a run and signal a microcontroller. If something like that interests you, I can post some more detail on it for you.

I am a little confused about you rolling a PVC tube. You are going to slide one tube over another one?

JDAWGBAILZ
02-20-2014, 01:26 PM
Yes and cut a slit in the outside one so the flag/curtain can unroll and roll back up. The inner pipe will be the one rolling, the outside one will just be a housing.


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iflights
02-20-2014, 01:35 PM
I agree with rotorhead. I used a similar concept to pull my animated nativity star up/down (I don't have a write-up on my page for it yet, but here is a video http://www.youtube.com/watch?v=3wAtDC-7jIE)

I use a wiper motor and switched directions using relays to reverse the voltage. I used reed switches and magnets to detect when I got to the end of a run and signal a microcontroller. If something like that interests you, I can post some more detail on it for you.

?

I love this, and have wanted to do this for a while, to hide star-like elements behind the hedges which are all over the front of the house. I would really appreciate you giving a bit more detail on your design.

toozie21
02-20-2014, 01:45 PM
I love this, and have wanted to do this for a while, to hide star-like elements behind the hedges which are all over the front of the house. I would really appreciate you giving a bit more detail on your design.

Sure. I had started to write-up a rough draft of what I was going to put on my website, but haven't gotten further. I'd be happy to share schematics, pics, videos, etc. if it helps (it will all end up on my site at some point anyway.

Here is a snippet of what I wrote pertaining to the star (the links in here are placeholders to remind me to put those in in the end):

Wanting to spice it up a little, I also made the star physically raise. It starts out by sitting turned off just behind the creche. When it turns on, a wiper motor (like the one used for a car's wiper blades) starts running, and it pulls the star up by using a pulley. At the end of the cycle, when everything turns off, the star then unwinds and lowers itself back to its starting position.

The problem with the star is that my lights are on a timer, so I don't know where the star was the previous night when the show turned off, so I have to have a way to get back to a "home" position. I also wasn't sure about how consistent the turning would be, so I wanted a way to sense when the star was at an upper position as well. What I did to solve that was use a rare earth magnet [link] and some reed switches [link] as sensors (this system is very similar to what a lot of alarm sensors use to detect if a window opened on a house).


The reed switch is a little device (about the size of a diode) that is always in an "open position" (meaning no current can flow through it it. But when a magnet gets close to it, the little switch inside "closes (it physically gets moved) and causes the switch to conduct electricity. So what I do is put 5 volts on one end of the switch all the time, then when I am doing one of my movements, I read the other end of the switch with the PIC and stop when I see 5V there (it is pulled down to ground with a weak pull-down so it is not floating). By doing this I can reset the star at the beginning of the night, and then I can detect when I am all the way up/down during the show.


As a safety factor (for my motor mostly), I do have a timer in my code that if I am moving the star and it doesn't reach the end point in a given amount of time, I stop trying for the night and only turn the light on/off the rest of the night. This protects me for if the rope gets hung up on something or gets twisted and the star will never get to the end.


To make the star go up and down, I setup the motor to run both directions. A wiper motor is a standard DC motor, meaning that if I put 5V and ground on one way, it will turn in one direction (say clockwise), and if I reverse the polarity, it will run the other (say counterclockwise). So what i did was setup two SPDT relays [link] that the microcontroller can activate and dictate which direction the motor turns. This allows me to wind up the string, or unwind it.

toozie21
02-20-2014, 01:47 PM
Yes and cut a slit in the outside one so the flag/curtain can unroll and roll back up. The inner pipe will be the one rolling, the outside one will just be a housing.


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OK, I assume that this is for the vertical motion (the inner PVC will go up/down)? If so, I think that a pulley idea would work fine. I just don't know how much weight you would be pulling up, that could make it a little tough.

JDAWGBAILZ
02-20-2014, 02:08 PM
The inner PVC pipe will spin and raise and lower the flag


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ErnieHorning
02-20-2014, 02:24 PM
I just don't know how much weight you would be pulling up, that could make it a little tough.If you need more torque, an old cordless drill can lift a lot of weight. Those old NiCad type can be found on Craigslist. Not worth buying a battery for them but they’re definitely good for hacking.

I remember starting the snow blower with mine, so I know the torque is there.

JDAWGBAILZ
02-20-2014, 02:27 PM
If you need more torque, an old cordless drill can lift a lot of weight. Those old NiCad type can be found on Craigslist. Not worth buying a battery for them but they’re definitely good for hacking.

I remember starting the snow blower with mine, so I know the torque is there.

What about an old electric drill?


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ErnieHorning
02-20-2014, 02:39 PM
What about an old electric drill?Depending on the motor type, most AC drills will run on DC. Just need to rectify the AC to DC. You can even reverse one that originally didn’t have that capability.

The difference is that you’re working with 120 volt instead.

JDAWGBAILZ
02-20-2014, 09:20 PM
Will this motor work?
http://www.ebay.com/itm/12V-15RPM-High-Torque-Gear-Box-Electric-Motor-Small-/360861587731

JDAWGBAILZ
02-20-2014, 09:28 PM
or this one?
http://www.ebay.com/itm/12V-300RPM-Torque-Gear-Box-Motor-New-/201037486382?pt=LH_DefaultDomain_0&hash=item2ecec4992e

JackFrost
02-22-2014, 05:01 PM
no... both of those are WAY too small to do what your looking to do . Not enough torque .
One , something like this might do , but , there is a LOT that would be needed to know to be positive .. like , the weight of the flag , the ratio of the pull ( meaning are you going to do a "direct" drive to the round PVC or are you going to gear it ?

http://www.ebay.com/itm/BODINE-34R6BFCI-W2-AC-GEARMOTOR-115-VAC-1-PHASE-1-9-HP-5-5-1-RATIO-/351002870261?pt=LH_DefaultDomain_0&hash=item51b966c1f5

Also , pulling up verses pulling sideways is different and would it be subject to possibly getting moist/wet which would of course add more weight to the pull , requiring more torque .
Now , if you were to gear it , from the motor to the PVC at a rate of approx 2:1 ratio , then , something like this might work ....

http://www.ebay.com/itm/12V-DC-60RPM-Torque-Gear-Box-Electric-Motor-For-ROBOT-/201039182622?pt=LH_DefaultDomain_0&hash=item2ecede7b1e

JDAWGBAILZ
02-27-2014, 05:54 PM
What relays will I need to reverse polarity to the motor. I want to have one channel for up and one channel for down. Can someone please help me with this?


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toozie21
02-27-2014, 06:10 PM
When i get in tonight I can send out the schematic of what I used I just bought some relays on eBay, I think most any will work, it is just how you set it up.

JDAWGBAILZ
02-27-2014, 06:18 PM
Ok thank you toozie! I just got my flag in the mail today and want to put it on the mechanism and try it with the motor asap


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LightUp
02-27-2014, 06:28 PM
What relays will I need to reverse polarity to the motor. I want to have one channel for up and one channel for down. Can someone please help me with this? Sent from my iPhone using Tapatalk

What I would do is to first see if I can rewire the motor to get the idea. Then replace the "manual wiring" with a toggle switch. Since you need to switch two wires on the motor a DPDT toggle switch would fit the bill. When that is working replace the toggle switch with a relay that has the same number of pins (i.e. DPDT) and can handle the voltage and current of your motor.

If you buy those SainSmart type relays, I think they are SPDT, so it will two of them but drive both optos from on channel.
http://www.sainsmart.com/arduino-compatibles-1/relay/4-channel-5v-relay-module-for-pic-arm-avr-dsp-arduino-msp430-ttl-logic.html
This relay can handle 30VDC @ 10A. I don't know what motor you are using so I can't say whether these specs are appropri
ate.

Edit: Why two channels? HIGH output is say FORWARD and LOW is REVERSE.

JDAWGBAILZ
02-27-2014, 06:34 PM
What I would do is to first see if I can rewire the motor to get the idea. Then replace the "manual wiring" with a toggle switch. Since you need to switch two wires on the motor a DPDT toggle switch would fit the bill. When that is working replace the toggle switch with a relay that has the same number of pins (i.e. DPDT) and can handle the voltage and current of your motor.

If you buy those SainSmart type relays, I think they are SPDT, so it will two of them but drive both optos from on channel.
http://www.sainsmart.com/arduino-compatibles-1/relay/4-channel-5v-relay-module-for-pic-arm-avr-dsp-arduino-msp430-ttl-logic.html
This relay can handle 30VDC @ 10A. I don't know what motor you are using so I can't say whether these specs are appropriate.
Rather then waste money on toggle switches I'm just gonna go straight for the relays. I got the schematic in my head as to how it needs wired. I was just wondering if somehow there was a way to control both directions with one relay rather than two but I thought about it and there isn't so I'm good to go as soon as the OP shows me what relays he used. I'm just hoping the motors I have are strong enough to turn the pipe to roll/unroll the flag/curtain. They are 12v 300 rpm motors geared down pretty far.


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LightUp
02-27-2014, 07:35 PM
Rather then waste money on toggle switches I'm just gonna go straight for the relays. I got the schematic in my head as to how it needs wired. I was just wondering if somehow there was a way to control both directions with one relay rather than two but I thought about it and there isn't so I'm good to go as soon as the OP shows me what relays he used. I'm just hoping the motors I have are strong enough to turn the pipe to roll/unroll the flag/curtain. They are 12v 300 rpm motors geared down pretty far. Sent from my iPhone using Tapatalk

I used the toggle switch as a way for you to visualize how to make it work and transpose that knowledge to a relay. I didn't know you had a schematic in your head. :)
Yes, a DPDT relay will work also, or even an H-Bridge, which would be solid state.

toozie21
02-27-2014, 07:54 PM
In the beginning, to prove stuff mechanically worked I would power up the motor, turn off power, reverse the wires, and then power it up again to work things out. Once I did that and was happy with things, I then did what is in this schematic: https://drive.google.com/file/d/0B3u2xTppuGAhZEdha0w1YllVYkU/edit?usp=sharing

If it doesn't make sense, let me know and I can try to explain (the part you are interested in is in the bottom left corner; that is used to control two motors, you would only need half for one motor).