www.robowars.org

RoboWars Australia Forum Index -> Off-Topic

motorised curtain?. Ok its not for robots but its got motors
Goto page 1, 2  Next

Post new topic   Reply to topic
  Author    Thread
miles&Jules
Experienced Roboteer


Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD


 Reply with quote  
motorised curtain?. Ok its not for robots but its got motors

Hi all ...planning to make a motorised curtain that lowers a white sheet over a black sheet. for our animation/matting work.

If you've ever seen those powered projector screens .....thats pretty much what we need to build in our shed.

The white sheets is about 2.5 by 3m with a strip of pvc pipe at the bottom to hold it all straight. Maybe a big piece of dowel for the top that the motor attaches to.

I'm thinking a hacked 12v drill motor at one end of each and a bearing at the other. Then running that to a blue speedo.(cause we have 3 of them) and we need at least 3 curtains. They can be remote control to with a hk tx&rx.

They will have to go up and back down every time we take a frame so on average it will need to do 200-500 wind ups and wind downs a day.

So What kind of ac to dc power pack would we need to run 3 drill motors at once ?
We got one of those 12v car jumper packs would that blow the blue speedos?

thanks for any suggestions!!!
_________________
Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Post Tue Aug 09, 2011 5:07 pm 
 View user's profile Send private message Send e-mail Visit poster's website
Nick
Experienced Roboteer


Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW


 Reply with quote  

Interesting project. You don't really need the speed controllers unless you really want wireless operation; just switches would do. You probably don't need a huge power supply either, unless the curtains are heavy. Its hard to estimate, but at 12V a drill motor might be drawing 8 to 10 amps hauling a light load.

If you want to get it right, I'd suggest building the curtain and using an ammeter to check the current.

Post Tue Aug 09, 2011 5:19 pm 
 View user's profile Send private message
Philip
Experienced Roboteer


Joined: 18 Jun 2004
Posts: 3842
Location: Queensland near Brisbane


 Reply with quote  

You might be best to put a car battery in between the charger and any speed controller. Could you use the drill's trigger to control the drills? If the drills go too fast, you could always try wind screen wiper motors.
_________________
So even the rain that falls isn't actually going to fill our dams and our river systems

Post Tue Aug 09, 2011 6:49 pm 
 View user's profile Send private message
miles&Jules
Experienced Roboteer


Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD


 Reply with quote  

Hi guys
Thanks for the suggestions. Yeah could use the drill trigger switches but I remember doing this on other camera moves etc frame by frame. but the triggeres start to hurt your hands after just a few moves.cause you got to hold it down the whole time its lifting or lowering. A regular on an off fwd rev 6pin switch would work I guess. I go and just start and see what happens.

Nick- I will try your ammeter trick to work out the amps!
Thanks
Miles
_________________
Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Post Tue Aug 09, 2011 7:29 pm 
 View user's profile Send private message Send e-mail Visit poster's website
Jaemus
Experienced Roboteer


Joined: 01 Apr 2009
Posts: 2674
Location: NSW


 Reply with quote  

yeah just use a three way switch and put some limit switches at the top and bottom of the screen - that way you can flick the switch and forget and it will stop the motor at the top or bottom

EDIT: youll flatten the Tx battery in a hobbyking radio repeatedly during one day of constant use
_________________
<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

Post Tue Aug 09, 2011 8:28 pm 
 View user's profile Send private message Send e-mail MSN Messenger
miles&Jules
Experienced Roboteer


Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD


 Reply with quote  

Hi Jaemus
Good thinking..... yeah those batteries in the tx would probably only last 3hrs (even with lipos)

I like the limit switch as well...the trick will be making it all reliable and repeatable with no budget x3...oh well thats normal.
_________________
Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Post Tue Aug 09, 2011 9:04 pm 
 View user's profile Send private message Send e-mail Visit poster's website
Nick
Experienced Roboteer


Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW


 Reply with quote  

From what you were saying about up to 500 frames with the curtains moving each time, you could really increase productivity by making the curtains move as fast and as automatically as possible, so the faster drill motors will make you money. You might also think about adding limit switches so the blinds stop automatically; here is a circuit ideas page: http://www.beam-wiki.org/wiki/Using_Limit_Switches

This idea might be way off as I haven't seen your setup: If you always do a transition between two colours, how about having a PVC pipe roller at the top, driven by a drill motor. rather than just lowering a sheet, you join the background colours end to end, forming a loop that hangs off the top roller but isn't attached to it. You put in a free-rolling pvc pipe at the bottom of the loop to keep it taut. That only needs one drill and no reverse, so your controls are much simpler. the motor current should also be lower as you are not really lifting anything, just rolling the loop in place.



Just rotate the loop half way to show the alternate colour. I don't know what your curtain material is, but if you are using rosco scenery paper, a bigger diameter roller will stop it going wavy with use - I went through background paper really fast when I was in TV and winding backgrounds on & off their narrow rolls.

Post Tue Aug 09, 2011 9:29 pm 
 View user's profile Send private message
miles&Jules
Experienced Roboteer


Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD


 Reply with quote  

Hi Nick
Love it! Cool limit switch link to! might give that a go....but I need to be able to stop it on each movement....spose that wouldn't be to hard!

We are doing a technique called front light back light.....sounds lame but what happens is you have your scene/puppets setup in front of the curtains. You have the puppets lighting on the puppet with a black background. You then take that frame. Then you move the background to white that is evenly lit and you turn the for ground puppet lights off. So you get a silhouette of the puppet against white. You take that frame. Then you move the puppet then repeat the process.

So in the end you nd up with two separate exposures for each frame of film. Then you chuck em into final cut or after effects and they matte each other out perfectly...with none of the fringing problems you get with green screen ect. It works great and if the white is very white (you get perfect matte effect) Then you can replace the background with what ever. Its a slows things down alot but thats the price you pay for an effect that works every time.

The easiest way to do it is with a big lcd screen behind the puppet. so you just turn the screen off for black and have a white desk top for white....that is the best but we need our whole shed to be able to do this for a big sequence with 1.2 meter sized miniature houses.

We already have the black curtains on our shed wall. So will try with just the wind up wind down technique first...but Im going to try your roller technique one day!
Thanks
Miles
_________________
Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Post Tue Aug 09, 2011 10:27 pm 
 View user's profile Send private message Send e-mail Visit poster's website
Nick
Experienced Roboteer


Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW


 Reply with quote  

Interesting, I never heard of that technique but it sounds great! In TV land, I had all sorts of problems with greenscreens, lighting them evenly was a nightmare.

If you can make the roller out of something wider (like PVC stormwater pipe) the gearing will be higher and the blind will move faster. If the drill motor struggles to lift the blind, you can easily counterweight it by making the top roller a bit longer and winding some cord in the opposite direction with a weight on the end. That way the drill will draw much less current.

Post Tue Aug 09, 2011 10:42 pm 
 View user's profile Send private message
miles&Jules
Experienced Roboteer


Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD


 Reply with quote  



Hi Nick

here is an example..no green screen nightmares and this is not from a composite programme like after effects, this is just off the final cut timeline. So its real easy to make a good composite...if only we did this technique from the beginning!

Cool...maybe we should do it that way. especially if quicker and easier on the drill!
thanks heaps
Miles
_________________
Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Post Tue Aug 09, 2011 11:51 pm 
 View user's profile Send private message Send e-mail Visit poster's website
miles&Jules
Experienced Roboteer


Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD


 Reply with quote  

http://vimeo.com/27523042

Hi Nick.... here it is in action...well its only a prototype but I think it will work after we get rid of that bend in the pipe. he he

Thanks again for the design idea!
_________________
Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Post Wed Aug 10, 2011 5:13 pm 
 View user's profile Send private message Send e-mail Visit poster's website
Jaemus
Experienced Roboteer


Joined: 01 Apr 2009
Posts: 2674
Location: NSW


 Reply with quote  

haha nice work Smile
_________________
<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

Post Fri Aug 12, 2011 12:05 pm 
 View user's profile Send private message Send e-mail MSN Messenger
miles&Jules
Experienced Roboteer


Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD


 Reply with quote  

Got the curtain working like Nick's in design. The only problem now is getting rid of the wrinkles. Will post a vid once/if its perfected.
_________________
Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Post Fri Aug 12, 2011 8:46 pm 
 View user's profile Send private message Send e-mail Visit poster's website
Nick
Experienced Roboteer


Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW


 Reply with quote  

WOW, your creation looks way bigger than I imagined! Getting the bend out of the roller might be difficult but its going to need to be straight whether you use a single loop or a regular roller blind. just a thought - what if you had two shorter blinds that overlapped a bit? the rollers would have half the length to support and if you arranged it cleverly, the join might be invisible. If you can straighten out the tube or find a stiffer replacement, that would still be the best bet.

Post Fri Aug 12, 2011 10:41 pm 
 View user's profile Send private message
miles&Jules
Experienced Roboteer


Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD


 Reply with quote  

Hi Nick..yeah I found a 4.5m length of 100mm drain pipe under the house. I was about to cut it to the length of the sheet...when I thought...lets see how big we can make this, so I left it (the bigger the better for shooting).

The bend actually doesn't seem t worry the motor. Been leaving it over night with the bend up(so hopefully it will unbend.) The trick will be getting the sheet without wrinkles. Planning to attach a thin strip of ali where the sheets join to stretch the sheets out straight. should be interesting......If we cant get it straight we will cut it into two lengths like you say.

I had a nightmare with the motor making stripping sounds, but it was just the high and low speed lever falling in between ..so I zip tied that into the low position.
_________________
Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Post Fri Aug 12, 2011 11:31 pm 
 View user's profile Send private message Send e-mail Visit poster's website
  Display posts from previous:      

Forum Jump:
Jump to:  

Post new topic   Reply to topic
Page 1 of 2

Goto page 1, 2  Next

Forum Rules:
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

 

Last Thread | Next Thread  >
Powered by phpBB: © 2001 phpBB Group
millenniumFalcon Template By Vereor.