DIY Motorized Dynamic Masking (DYNAMASK 2000) - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
 88Likes
Reply
 
Thread Tools
post #1 of 86 Old 01-15-2020, 06:52 AM - Thread Starter
Senior Member
 
MinHeadroom's Avatar
 
Join Date: Feb 2019
Location: North Jersey/ NYC
Posts: 434
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 144 Post(s)
Liked: 205
DIY Motorized Dynamic Masking (DYNAMASK 2000)

I hate limiting options, and I like engineering problems.

Problem: I am unwilling to commit to a screen size.
1) I know I’ll want extra wide 2.39:1, but at a first row between 9.5’ and 8’ (adjustable on rollers), I am uncertain if I really want a 120” wide screen.
2) I want the option for GIGANTIC 16:9 action, but I don’t really think I need to watch basic TV with the wife on a gigantic screen.

So, this yields three possible sizes. I could build fixed frame masks, but uncertainty is hard to spec out. Also, I don’t want to deal with hiding unused masks. Since I am building a screen wall and screen, why not build some affordable dynamic masking?

Proposed Mechanism: Thankfully, there are inexpensive (read, not Somfy) motors for about $60 a pop on Amazon which fit standard 1.5” OD tubes. Tubes with the correct ID can be purchased at Home Depot for cheap.

Got one of these incoming:

And one of these:


Any advice (outside of abandoning the project) is appreciated. If this works, I hope to make a DIY post so this is easily reproducible.
tjambro, Lynkage and DunMunro like this.

Last edited by MinHeadroom; 01-15-2020 at 07:27 AM.
MinHeadroom is offline  
Sponsored Links
Advertisement
 
post #2 of 86 Old 01-15-2020, 07:43 AM
Advanced Member
 
Join Date: Aug 2018
Location: Zimmerman MN
Posts: 731
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 269 Post(s)
Liked: 910
No advice but thanks for taking this on and I look forward to seeing it play out. I would love to add automated masking to my build.
MinHeadroom likes this.

My Theater Build - Full Circle Cinema
pkinneb is online now  
post #3 of 86 Old 01-15-2020, 08:09 AM
AVS Forum Special Member
 
sirjaymz's Avatar
 
Join Date: Dec 2008
Location: Houston<>Anchorage
Posts: 1,046
Mentioned: 36 Post(s)
Tagged: 2 Thread(s)
Quoted: 488 Post(s)
Liked: 600
You might want to reach out to @Little Chris , as he's built a masking system for his HT build. He ran into some pitfalls, and was able to figure out some solutions for his design.
MinHeadroom likes this.

HT1.0 | HT2.05
JVC RS-2000 / Seymour AV Center Stage 130"diag, 2.35 / nVidia Shield
11.2(22).6 Atmos / Denon 7200WA / Denon 6300 / 2x miniDSP2x4HD / DIY treatments
2x NU6000DSP / 2x NU3000DSP / 2x Klipsch R-112SW / 4x UM18-22 / 4x PA-460 / 12x JBL 12"
Klipsch RF-82/RC-64II/RS-42/RS-41/BS-62/CDT3800-C-II
sirjaymz is offline  
Sponsored Links
Advertisement
 
post #4 of 86 Old 01-15-2020, 10:30 AM
Senior Member
 
tjambro's Avatar
 
Join Date: May 2003
Location: IN
Posts: 460
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 45 Post(s)
Liked: 128
Looking forward to what you come up with as I hate engineering problems!

Sent from my SM-N975U using Tapatalk
MinHeadroom likes this.
tjambro is online now  
post #5 of 86 Old 01-15-2020, 11:52 AM
AVS Forum Special Member
 
bud16415's Avatar
 
Join Date: Jan 2006
Location: Erie Pa
Posts: 8,086
Mentioned: 119 Post(s)
Tagged: 0 Thread(s)
Quoted: 2252 Post(s)
Liked: 1175
Hi @MinHeadroom

There seems to be a growing enthusiasm with variable image sizing and I even started a thread in the CIH forum on the subject. Right now there is a thread here on Rob Hahn getting the HT of the decade award and he does something similar with automated 4way masking on a grand scale. In that thread I asked him about this and any future plans and his answers along with answers from his theater designer were very interesting and a good read.

I was a automation machine designer for 43 years and retired now so building a 4way system is something I could do and have given great thought. I had manual 4way with manual zoom and shift and focus for about 3 years and it was fun setting it all up for a presentation but it also got old. Family and friends never got it and suggested I pick a size and live with it as they didn’t much care as long as they saw a movie. Then came streaming and prestige TV and media coming at us in every direction even network TV some of it warrants big immersive viewing. Even TV is no longer just 16:9 and more commercials are in scope than ever before. Then there is IMAX and IMAX enhanced and the IMAX AR shifters that are imposable to mask.

I didn’t want to put my seating on rollers but even considered that and I also started noticing my like for immersion wasn’t always my guests. Thus the reasons commercial theaters have so many rows.

I noticed when I showed Dunkirk an AR shifting movie no one seemed to care the masking was fixed. I even asked them and they answered with a question like “ Are you saying the size of the picture changed?”

About that time I chucked it all and went with a .5 gain neutral gray stealth screen wall and let the chips fall where they may with self masking I have a dark chip 3 DLP and to do my zooming I mounted my ceiling projector on an inclined track with counterbalance with the projector all the way back it is my IMAX immersion with projectors widest zoom. Once focused I never touch the projectors controls and slide the projector for zoom and the incline provides the offset and the DOF maintains focus. I can zoom well beyond CIH now with a projector that wouldn’t do it before and the full range only takes 5 seconds to do. The dark screen is not perfect but is more than good enough given the simplicity of the setup and the outcome it provides.

Just thought I would share what works for me and will follow along with your project.
Lynkage, DunMunro and MinHeadroom like this.

Bud
bud16415 is online now  
post #6 of 86 Old 01-15-2020, 03:21 PM - Thread Starter
Senior Member
 
MinHeadroom's Avatar
 
Join Date: Feb 2019
Location: North Jersey/ NYC
Posts: 434
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 144 Post(s)
Liked: 205
Quote:
Originally Posted by sirjaymz View Post
You might want to reach out to @Little Chris , as he's built a masking system for his HT build. He ran into some pitfalls, and was able to figure out some solutions for his design.


Thank you everybody for the words of encouragement and personal experiences, and thank you to @sirjaymz for referring me to: https://r.tapatalk.com/shareLink/top...ink_source=app

I plan to do 4-way masking, with each side independently controlled. I am still slightly considering having a belt drive linking parallel masks, though that might be more cumbersome and even more expensive.

One of the most challenging parts is a compact way to provide tension. I considered (and continue to consider):
- bungees
- weights
- belt drives that ensure everything is connected and thereby tensioned
- linear tension springs
- spiral tension springs

As my above Amazon orders show, I am going to examine the spiral tension ring in a retractable clothes line. It was cheap. Also, fun fact, spiral springs apparently apply a constant force! This is apparently why they replaced water and gravity in clocks (my speculation).



Bungees could work well, but they require space and experimentation.

Weights and pulleys are probably the most simple mechanism, but did I mention the thing (and my screen) need to lift up to access tge utilities


(Next project will be putting some gas struts and an actuator on it, tee hee)

Belt drives are tough as I need to source an inexpensive part AND, the bigger problem, as the roller holding the mask unrolls, the linear rate of fabric exiting will slow down in relation to the leading edge, making it a challenge to keep tension on the mask. Perhaps a small spring interrupting a belt drive might suffice.

Decisions, decisions...
MinHeadroom is offline  
post #7 of 86 Old 01-16-2020, 03:13 PM
AVS Forum Special Member
 
ScottAvery's Avatar
 
Join Date: Mar 2002
Location: Great Falls, VA
Posts: 1,946
Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 821 Post(s)
Liked: 236
How do you intend to control the positioning? Will you just have two stops, or will there be programmed intermediate stops? I am trying to decide between a stepper motor or linear actuator with a custom programmed controller vs a commercial roller blind motor like you posted. I have seen a great somfy solution that used bungees for the opposing force, but I don't want to commit to somfy pricing, either, for an experiment. The bungees do allow it to be self contained such that the whole arrangement could be lifted as you require.

This one is for a curved screen, but has the bungees I think:
https://www.avsforum.com/forum/174-d...d-masking.html

Another one for you:
https://www.avsforum.com/forum/174-d...o-masking.html
ScottAvery is online now  
post #8 of 86 Old 01-16-2020, 04:21 PM - Thread Starter
Senior Member
 
MinHeadroom's Avatar
 
Join Date: Feb 2019
Location: North Jersey/ NYC
Posts: 434
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 144 Post(s)
Liked: 205
Quote:
Originally Posted by ScottAvery View Post
How do you intend to control the positioning? Will you just have two stops, or will there be programmed intermediate stops? I am trying to decide between a stepper motor or linear actuator with a custom programmed controller vs a commercial roller blind motor like you posted. I have seen a great somfy solution that used bungees for the opposing force, but I don't want to commit to somfy pricing, either, for an experiment. The bungees do allow it to be self contained such that the whole arrangement could be lifted as you require.



This one is for a curved screen, but has the bungees I think:

https://www.avsforum.com/forum/174-d...d-masking.html



Another one for you:

https://www.avsforum.com/forum/174-d...o-masking.html


Thanks ScottAvery!
Those links aren’t opening, I suspect because I’m on the train.

1) and 2) Positioning: the cheapo guy I ordered from the first post apparently has RF controlled presets. If it allows multiple positions, I want 4: fully closed (to keep grubby kid hands off), 16:9 gigantic IMAX, 2.39:1 scope, and 16:9 sane viewing size (i joked to my wife we never need an immersive news broadcast or presidential debate).

The RF I’ll control from a cheap Broadcom unit (they are very hackable, $30, link to follow) that I can control from my HA platform via IP commands. Honestly I’m fine with controlling them with an IP controlled relay and skipping the radio, but the radios were included (this option involves disassembly/ soldering).

If it DOESN’T have that many presets from RF control, it’s time to get creative. Limit switches and timed rolling/ unrolling becomes an option (links to follow).

Re: stepper vs linear actuator. I love both of these, and considered them. The linear actuators, at lengths I want, are more expensive, and they involve a place for the masks to “hide” when not in use, unless I spring-load or bungee-load the fabric rolls. I considered steppers because they’re so easily controlled from an Arduino, ESP8266, or raspi, but the price of the motor, driver, and mounting hardware just made these pre-cooked rollers more preferable. I may be wrong.

I read more about bungee properties than i care to admit last night. They seem like the simplest option if I cannot get spiral springs to work. I AM concerned about the variable force of the bungee, as it pulls harder when extended completely, and barely pulls when only slightly extended. I ordered 1/8” bungee with a 125% elasticity rating. We’ll see how that works. Using pulleys in efforts to have more bungee, less extension, might be a solution.

I’ll post some half-baked sketches soon, and definitely let me know if I’m missing something. Thanks again!
MinHeadroom is offline  
post #9 of 86 Old 01-16-2020, 04:59 PM
AVS Forum Special Member
 
ScottAvery's Avatar
 
Join Date: Mar 2002
Location: Great Falls, VA
Posts: 1,946
Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 821 Post(s)
Liked: 236
Quote:
Originally Posted by MinHeadroom View Post



Thanks ScottAvery!
Those links aren&#226;€&#x2122;&#xfe0f;t opening, I suspect because I&#226;€&#x2122;&#xfe0f;m on the train.

1) and 2) Positioning: the cheapo guy I ordered from the first post apparently has RF controlled presets. If it allows multiple positions, I want 4: fully closed (to keep grubby kid hands off), 16:9 gigantic IMAX, 2.39:1 scope, and 16:9 sane viewing size (i joked to my wife we never need an immersive news broadcast or presidential debate).

The RF I&#226;€&#x2122;&#xfe0f;ll control from a cheap Broadcom unit (they are very hackable, $30, link to follow) that I can control from my HA platform via IP commands. Honestly I&#226;€&#x2122;&#xfe0f;m fine with controlling them with an IP controlled relay and skipping the radio, but the radios were included (this option involves disassembly/ soldering).

If it DOESN&#226;€&#x2122;&#xfe0f;T have that many presets from RF control, it&#226;€&#x2122;&#xfe0f;s time to get creative. Limit switches and timed rolling/ unrolling becomes an option (links to follow).

Re: stepper vs linear actuator. I love both of these, and considered them. The linear actuators, at lengths I want, are more expensive, and they involve a place for the masks to &#226;€œhide&#226;€ when not in use, unless I spring-load or bungee-load the fabric rolls. I considered steppers because they&#226;€&#x2122;&#xfe0f;re so easily controlled from an Arduino, ESP8266, or raspi, but the price of the motor, driver, and mounting hardware just made these pre-cooked rollers more preferable. I may be wrong.

I read more about bungee properties than i care to admit last night. They seem like the simplest option if I cannot get spiral springs to work. I AM concerned about the variable force of the bungee, as it pulls harder when extended completely, and barely pulls when only slightly extended. I ordered 1/8&#226;€ bungee with a 125% elasticity rating. We&#226;€&#x2122;&#xfe0f;ll see how that works. Using pulleys in efforts to have more bungee, less extension, might be a solution.

I&#226;€&#x2122;&#xfe0f;ll post some half-baked sketches soon, and definitely let me know if I&#226;€&#x2122;&#xfe0f;m missing something. Thanks again!
Did not realize you wanted 4 way masking. That does complicate things but there are diys out there for it.
Mini magnetic Contact switches might be easiest but I worry I would need to make adjustments and would prefer continuously variable if possible. Stepper seems easiest to control but linear actuator easier to position. I am going for curved ultimately, so pulleys be to be involved. If I use a linear actuator it will have a stroke of half the movement and I will just fold the draw string back on a pulley.

I like the idea of pulling from the middle (opposite side, actually) so the movement is linear rather than slightly exponential as in the designs that are powered from the roller. That also lets you use a standard internal spring in the roller tube, with the clutch removed.
ScottAvery is online now  
post #10 of 86 Old 01-16-2020, 05:36 PM - Thread Starter
Senior Member
 
MinHeadroom's Avatar
 
Join Date: Feb 2019
Location: North Jersey/ NYC
Posts: 434
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 144 Post(s)
Liked: 205
DIY Motorized Dynamic Masking (DYNAMASK 2000)

Quote:
Originally Posted by ScottAvery View Post
Did not realize you wanted 4 way masking. That does complicate things but there are diys out there for it.
Mini magnetic Contact switches might be easiest but I worry I would need to make adjustments and would prefer continuously variable if possible. Stepper seems easiest to control but linear actuator easier to position. I am going for curved ultimately, so pulleys be to be involved. If I use a linear actuator it will have a stroke of half the movement and I will just fold the draw string back on a pulley.

I like the idea of pulling from the middle (opposite side, actually) so the movement is linear rather than slightly exponential as in the designs that are powered from the roller. That also lets you use a standard internal spring in the roller tube, with the clutch removed.


Firstly- THANK YOU for the inspirational links! I love the deep track from 2010, and the ise of a weight in the 2016 thread.

You are correct in that 4-way masking is 3d spatially challenging; it reminds me of organic chemistry.

My two spring loaded clothes-lines just arrived. I plan to measure the force of their pull tonight and I hope to post some numbers. I am flirting with welding up the frame, as I bought a cheapo-death-wish-stick-welder from Amazon that I LOVE, and steel stays in spec soooo much better than wood (for me).

It sounds like you are going two-way curved? In that case, I would definitely consider stepper motors (half the price of 4-way) and a weight, assuming you won’t need to move it when the meter reader comes like I do. The weighted system just gives you such precise control of the force involved. I would also consider wrapping a wire (connected to a weight) around the tube (holding the mask), then using stepper motors to pull the masks inward. Heck, one stepper motor could easily pull in both masks if you want them symmetrical. It would be faster too if you use the newer stepper library on an Arduino (i can find the link if you need it).

Measurements on spring mechanisms to follow!

Edit: Can you direct me to spring loaded roller tubes for sale? It’s a harder part to find than I thought!
MinHeadroom is offline  
post #11 of 86 Old 01-16-2020, 09:39 PM
AVS Forum Special Member
 
ScottAvery's Avatar
 
Join Date: Mar 2002
Location: Great Falls, VA
Posts: 1,946
Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 821 Post(s)
Liked: 236
Quote:
Originally Posted by MinHeadroom View Post
Edit: Can you direct me to spring loaded roller tubes for sale? It’s a harder part to find than I thought!
Any generic pulldown roller blind has an internal spring. The Home Depot type. The standard operation is to pull it down then a clutch stops it. You do a little tug and release to send it back up. You can remove the clutch mechanism so there is continuous tension. Useful for something like a skylight or high window where you have to use a cleat to tie the blind down because you can't reach it directly.

Something like this:

https://www.amazon.com/Levolor-SRSHW...dp/B015G8K8ZM/
ScottAvery is online now  
post #12 of 86 Old 01-17-2020, 07:40 AM - Thread Starter
Senior Member
 
MinHeadroom's Avatar
 
Join Date: Feb 2019
Location: North Jersey/ NYC
Posts: 434
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 144 Post(s)
Liked: 205
DIY Motorized Dynamic Masking (DYNAMASK 2000)

Bungee Math:

First, my super scientific test bed:



First I checked the pull on the spiral coils.


Just like wikipedia said, they had fairly constant force that was independent of how far i pulled. Unfortunately, they only provided 0.3-0.4 lbs of pull, which is inadequate for the side masks, and definitely inadequate for the bottom. The funny part is I hoped I could just wind the spring tighter, but the whole “constant force” kinda means that will not work.

Next up: 1/8” bungee. It has an “elasticity” of 125%, which means 1 foot can stretch to 2.25 feet (i think, 100% means it can double its length).

Now, obviously when at rest, the force of 1 bungee is 0 lbs.

Time for some metrics:
#Bungees[/URL] Stretch(%) Force (lbs)
1 50 0.9
1 100 2.1
2 50 1.2
2 100 4.3

Pics:


Okay, what did we learn about bungee tensioning properties:
1. They need to be stretched even at their least-stretched position to maintain a force. I’m estimating around 25-50% is a good minimum.
2. The pulling force increases as it is stretched. I’m not sure if this is linear or quadratic, but I probably don’t need to get into it.

So, say I have a 10 foot wide screen, and say I want to pull side masks on motorized rollers towards the center (5 feet each):
- I need bungee in a length that provides reasonable force over the 5 feet.
- I need the minimum length of the bungee to be about 1.25x it’s original (unstretched) length, and the maximum length (e.g. when the mask is fully wound back on it’s roll) to be 2x it’s original (unstretched) length.

This means 5 feet of “mask travel” needs a bungee that, unstretched, conforms to:
2x - 1.25x = 5 feet
.75x = 5 feet
x = 6.66 feet

(The BUNgee OF the BEAST!)

At full extension, when the mask is fully withdrawn, the bungee will stretch 6.66 * 2 = 13’4”
When the mask is fully closed, the 6.66 foot bungee will be stretched 6.66 * 1.25 = 8’4”

The next question that comes to mind: how do I keep that much bungee in a low-profile space? My first thought is using 1 or two fixed pulleys to wrap it up. Designs to follow.

PS- I know this looks like finger painting compared to stuff i read on the DIY subwoofer forum!

PPS- These stretch ratios are actually pretty convenient. A 10’ wide 16:9 screen is 5.625’ tall. At full extension, a bungee can travel half the width of the screen (5’), double back over a pulley (5’), and travel halfway down the height (2.125’). That 12.125’ is already really close to our desired 13’4” at full extension, and it is 5’ + 2.125’ at full withdrawal (with the mask closed)

LUCKILY, this means the SAME bungee should work perfectly for both sides of the mask, and the tension on the top and bottom of the mask will always be the same! Go arithmetic!

Last edited by MinHeadroom; 01-17-2020 at 08:09 AM.
MinHeadroom is offline  
post #13 of 86 Old 01-17-2020, 07:48 AM
AVS Forum Special Member
 
Audixium's Avatar
 
Join Date: Sep 2007
Location: Rocky Mtn High
Posts: 1,784
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 74 Post(s)
Liked: 100
Hurry up already and finalize the recipe!

I plan to start my screenwall build this weekend. If you go back in my thread 10 years this type of masking system is exactly what I wanted back then.
MinHeadroom likes this.
Audixium is offline  
post #14 of 86 Old 01-17-2020, 08:10 AM - Thread Starter
Senior Member
 
MinHeadroom's Avatar
 
Join Date: Feb 2019
Location: North Jersey/ NYC
Posts: 434
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 144 Post(s)
Liked: 205
DIY Motorized Dynamic Masking (DYNAMASK 2000)

Quote:
Originally Posted by Audixium View Post
Hurry up already and finalize the recipe!



I plan to start my screenwall build this weekend. If you go back in my thread 10 years this type of masking system is exactly what I wanted back then.


Read above, I think i gotta simple recipe!

Edit: It bears stating- I want the masks to ENTIRELY open and close- it’s a cool iris effect so I figured, “why not?” If your mask travel is significantly less (in relation to your screen size), then this can be done with a lot less bungee.

Last edited by MinHeadroom; 01-17-2020 at 08:20 AM.
MinHeadroom is offline  
post #15 of 86 Old 01-17-2020, 08:23 AM
Member
 
weavinator's Avatar
 
Join Date: Jan 2018
Posts: 171
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 73 Post(s)
Liked: 160
I'm away for two days and look what happens! I'm still reading through all this but I've also decided to attempt 4 way masking and have been kicking design ideas around in my head for a while now.

For what it's worth, I'm considering belts and stepper motors with ridgid masking panels.
MinHeadroom likes this.
weavinator is offline  
post #16 of 86 Old 01-17-2020, 09:40 AM
Senior Member
 
Join Date: Mar 2017
Location: Birmingham,Alabama
Posts: 401
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 193 Post(s)
Liked: 249
I always love these complex engineering threads - you guys with this knowledge amaze me. I'm damn handy with woodworking and pretty much anything around the house - but this type of engineering eludes me. Looking forward to following along.
tjambro, pkinneb and MinHeadroom like this.

Roll Tide.
p3bham is offline  
post #17 of 86 Old 01-17-2020, 12:52 PM - Thread Starter
Senior Member
 
MinHeadroom's Avatar
 
Join Date: Feb 2019
Location: North Jersey/ NYC
Posts: 434
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 144 Post(s)
Liked: 205
Thanks fellas! @weavinator , I would love if you shared your design!
MinHeadroom is offline  
post #18 of 86 Old 01-17-2020, 01:01 PM
Member
 
weavinator's Avatar
 
Join Date: Jan 2018
Posts: 171
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 73 Post(s)
Liked: 160
Quote:
Originally Posted by MinHeadroom View Post
Thanks fellas! @weavinator , I would love if you shared your design!
I don't have anything to show yet. Once I narrow down some parts choices I will start to prototype.
MinHeadroom likes this.
weavinator is offline  
post #19 of 86 Old 01-17-2020, 07:31 PM
AVS Forum Special Member
 
bluer101's Avatar
 
Join Date: Mar 2005
Location: South Florida
Posts: 2,443
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 651 Post(s)
Liked: 799
I still need to do mine. I’m going to use linear actuators for my CIW masking.
pkinneb likes this.
bluer101 is offline  
post #20 of 86 Old 01-17-2020, 08:21 PM
Advanced Member
 
Join Date: Aug 2018
Location: Zimmerman MN
Posts: 731
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 269 Post(s)
Liked: 910
Quote:
Originally Posted by bluer101 View Post
I still need to do mine. I’m going to use linear actuators for my CIW masking.
You really do, since a copied a bunch of other stuff from your build I could copy that as well
bluer101 and Lynkage like this.

My Theater Build - Full Circle Cinema
pkinneb is online now  
post #21 of 86 Old 01-17-2020, 08:46 PM
AVS Forum Special Member
 
ScottAvery's Avatar
 
Join Date: Mar 2002
Location: Great Falls, VA
Posts: 1,946
Mentioned: 26 Post(s)
Tagged: 0 Thread(s)
Quoted: 821 Post(s)
Liked: 236
Quote:
Originally Posted by MinHeadroom View Post
Read above, I think i gotta simple recipe!

Edit: It bears stating- I want the masks to ENTIRELY open and close- it’s a cool iris effect so I figured, “why not?” If your mask travel is significantly less (in relation to your screen size), then this can be done with a lot less bungee.
You got me thinking about this problem more now, but I would not bother with a full iris effect as there is not much need for the verticals to move very far in my use case. I couldn't see the top and bottom moving more than a few inches where the sides would need to move 6 feet each. I'm thinking I might try to just move the screen border itself for the top and bottom.
ScottAvery is online now  
post #22 of 86 Old 01-17-2020, 08:55 PM - Thread Starter
Senior Member
 
MinHeadroom's Avatar
 
Join Date: Feb 2019
Location: North Jersey/ NYC
Posts: 434
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 144 Post(s)
Liked: 205
Quote:
Originally Posted by ScottAvery View Post
You got me thinking about this problem more now, but I would not bother with a full iris effect as there is not much need for the verticals to move very far in my use case. I couldn't see the top and bottom moving more than a few inches where the sides would need to move 6 feet each. I'm thinking I might try to just move the screen border itself for the top and bottom.


Smart and practical. At a minimum, I would like the mask coming down from the top and the mask coming up from the bottom to close entirely, purely to keep my filthy spawns’ hands off my as of yet unmade screen. Thankfully, I am fond of them
MinHeadroom is offline  
post #23 of 86 Old 01-18-2020, 05:47 AM
HOME THEATER CONTRACTOR
 
BIGmouthinDC's Avatar
 
Join Date: Jan 2003
Location: Northern VA
Posts: 32,872
Mentioned: 474 Post(s)
Tagged: 5 Thread(s)
Quoted: 6228 Post(s)
Liked: 5956
worth watching it may give you some ideas:
farkem and MinHeadroom like this.
BIGmouthinDC is offline  
post #24 of 86 Old 01-19-2020, 02:16 PM - Thread Starter
Senior Member
 
MinHeadroom's Avatar
 
Join Date: Feb 2019
Location: North Jersey/ NYC
Posts: 434
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 144 Post(s)
Liked: 205
DIY Motorized Dynamic Masking (DYNAMASK 2000)

Quote:
Originally Posted by BIGmouthinDC View Post
worth watching it may give you some ideas:
https://www.youtube.com/watch?v=JPf9j_Ejh_U


Thanks Big.

I’m on vacation in a warm place. Here are some of my less-than-scientific sketches, if only to prove I have a concept








Last edited by MinHeadroom; 01-19-2020 at 02:21 PM.
MinHeadroom is offline  
post #25 of 86 Old 01-30-2020, 04:06 PM
sor
Senior Member
 
sor's Avatar
 
Join Date: Sep 2005
Location: UT
Posts: 402
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 155 Post(s)
Liked: 157
DIY Motorized Dynamic Masking (DYNAMASK 2000)

This is a very interesting thread. I had some similar ideas, though I plan to buy ready made parts and basically just assemble them as though I bought a pro kit. I’ve been researching the parts needed and I think it is very doable to not have to custom make anything.

It’s too bad that I’m probably 3-4 months out from starting, we could collaborate on a design. I’ve been looking at the aluminum framing extrusions pro companies use and I can buy the frame parts, with a built in masking track, and all of the brackets and bolts, just put it together.

Regarding bungee- I think it would work well if you don’t intend to have a full mask/iris. If you are just going from 4:3 to 2.4:1 you only need maybe 30-50% stretch, pre tension it and it and can maintain a fairly even pressure without having a very long bungee. Otherwise you’re probably looking at weights or springs or some way to manage a long bungee.

I had planned to keep the bungee simple and actually just join the opposite sides of the masks with one bungee line. Just tie the sliders together with them. Obviously that won’t work if you need to have 10’ of bungee to get your full stretch but I only need 24” or so of play on either side- a 135” tensioned bungee to stretch to 180”.
MinHeadroom likes this.

Last edited by sor; 01-30-2020 at 04:13 PM.
sor is online now  
post #26 of 86 Old 01-30-2020, 04:40 PM
sor
Senior Member
 
sor's Avatar
 
Join Date: Sep 2005
Location: UT
Posts: 402
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 155 Post(s)
Liked: 157
DIY Motorized Dynamic Masking (DYNAMASK 2000)

This is the sort of thing I’m talking about:


https://8020.net



One front facing slot is for hooks/mounting screen, the other slot is for a Delrin track slider:



Or one could do linear track bearings for an ultra smooth slide.

There are tons of struts and bolts and things to join and hang things off of this channel. You can also order it cut to size.

The aluminum T slot has an outside channel on top that can be used with L brackets to attach the outer mask frame and attach the roller assemblies.

For dual mask things get a bit tricky because you have to have a track on the outside of one of the rollers, but not impossible with proper planning. I was also thinking it might be possible to wrap the rollers around and mount on the back, which would simplify dual mask and the width required to hide the roller and the outside track.

At any rate you can see how with some planning you could just buy the whole kit and bolt it all together, not a lot of custom fabrication. I plan on calling it the SPM (Simple
Pro Masking) method. It’s not going to be the absolute cheapest way to do it but will be far cheaper than a purchased system and far easier than most DIY.
Tedd, ScottAvery and MinHeadroom like this.

Last edited by sor; 01-30-2020 at 05:43 PM.
sor is online now  
post #27 of 86 Old 01-31-2020, 05:48 AM
AVS Forum Special Member
 
Tedd's Avatar
 
Join Date: May 2001
Posts: 9,465
Mentioned: 134 Post(s)
Tagged: 0 Thread(s)
Quoted: 2268 Post(s)
Liked: 977
8020 is actually used in large masking systems.


Is this a 4 way mask or simply scope masking?

That anodized 8020 and Delrin sliders sure look like they have the potential to make two way making simpler. If this is to be scope masking, I wonder why not four sections of 4 T-slot rails
connected to a L angle profile, which would hide screen lacing and establish the upper and lower screen edges of the screen? Two side panels in front, could slide and establish the screen's
width edges. The 4 T-slot rails could be host wheels, gears, or sprockets at the ends and a 3rd (and maybe a 4th) gear could bring the drive back of the screen, to clear a servomotor and
create a tensioning system. An Audruino could control the motors and create various stop positions.

I am looking at simply doing a big 16x9 screen for the next theater, and thinking even simpler with a single upper mask, gravity drop and reuse the existing Somfy motor in my Draper
horizontal masking system. I was thinking of using 8020 to create the guide outside of the angle iron frame, and build a guide. I never knew 8020 was available in black anodized, and those
Delrin slides existed, so thank you sor for posting that. I think you just handed me an easy solution right there.
MinHeadroom likes this.
Tedd is offline  
post #28 of 86 Old 01-31-2020, 07:05 AM
AVS Forum Special Member
 
markmon1's Avatar
 
Join Date: Dec 2006
Posts: 7,004
Mentioned: 130 Post(s)
Tagged: 0 Thread(s)
Quoted: 5841 Post(s)
Liked: 3915
Quote:
Originally Posted by MinHeadroom View Post
Thanks ScottAvery!
Those links aren’t opening, I suspect because I’m on the train.

1) and 2) Positioning: the cheapo guy I ordered from the first post apparently has RF controlled presets. If it allows multiple positions, I want 4: fully closed (to keep grubby kid hands off), 16:9 gigantic IMAX, 2.39:1 scope, and 16:9 sane viewing size (i joked to my wife we never need an immersive news broadcast or presidential debate).

The RF I’ll control from a cheap Broadcom unit (they are very hackable, $30, link to follow) that I can control from my HA platform via IP commands. Honestly I’m fine with controlling them with an IP controlled relay and skipping the radio, but the radios were included (this option involves disassembly/ soldering).

If it DOESN’T have that many presets from RF control, it’s time to get creative. Limit switches and timed rolling/ unrolling becomes an option (links to follow).

Re: stepper vs linear actuator. I love both of these, and considered them. The linear actuators, at lengths I want, are more expensive, and they involve a place for the masks to “hide” when not in use, unless I spring-load or bungee-load the fabric rolls. I considered steppers because they’re so easily controlled from an Arduino, ESP8266, or raspi, but the price of the motor, driver, and mounting hardware just made these pre-cooked rollers more preferable. I may be wrong.

I read more about bungee properties than i care to admit last night. They seem like the simplest option if I cannot get spiral springs to work. I AM concerned about the variable force of the bungee, as it pulls harder when extended completely, and barely pulls when only slightly extended. I ordered 1/8” bungee with a 125% elasticity rating. We’ll see how that works. Using pulleys in efforts to have more bungee, less extension, might be a solution.

I’ll post some half-baked sketches soon, and definitely let me know if I’m missing something. Thanks again!
In my masking system, I use an IP controlled 8-relay system that plugs into ethernet. You can then turn something on or off for N seconds to hit a specific set point. This is the relay I use. It's extremely easy to program. I'd be happy to help. It runs track actuators.
https://www.amazon.com/gp/product/B07QM546BC
MinHeadroom likes this.

Video: JVC RS4500 135" screen in pure black room no light, htpc nvidia 1080ti.
Audio: Anthem mrx720 running 7.1.4, McIntosh MC-303, MC-152, B&W 802d3 LR, B&W HTM1D3 center, B&W 805d3 surround, B&W 702S2 rear, B&W 706s2 x 4 shelf mounted for atmos, Infinite Baffle Subs 4x15 fi audio running on behringer ep4000 + 2x12 fi audio mounted in main chair firing into back.
markmon1 is offline  
post #29 of 86 Old 01-31-2020, 07:52 AM
sor
Senior Member
 
sor's Avatar
 
Join Date: Sep 2005
Location: UT
Posts: 402
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 155 Post(s)
Liked: 157
DIY Motorized Dynamic Masking (DYNAMASK 2000)

Quote:
Originally Posted by Tedd View Post
8020 is actually used in large masking systems.



https://www.youtube.com/watch?v=ICWkLEgnPZ8



Is this a 4 way mask or simply scope masking?



That anodized 8020 and Delrin sliders sure look like they have the potential to make two way making simpler. If this is to be scope masking, I wonder why not four sections of 4 T-slot rails

connected to a L angle profile, which would hide screen lacing and establish the upper and lower screen edges of the screen? Two side panels in front, could slide and establish the screen's

width edges. The 4 T-slot rails could be host wheels, gears, or sprockets at the ends and a 3rd (and maybe a 4th) gear could bring the drive back of the screen, to clear a servomotor and

create a tensioning system. An Audruino could control the motors and create various stop positions.



I am looking at simply doing a big 16x9 screen for the next theater, and thinking even simpler with a single upper mask, gravity drop and reuse the existing Somfy motor in my Draper

horizontal masking system. I was thinking of using 8020 to create the guide outside of the angle iron frame, and build a guide. I never knew 8020 was available in black anodized, and those

Delrin slides existed, so thank you sor for posting that. I think you just handed me an easy solution right there.


Yeah, that’s where I began thinking about all of this. I noticed a B stock pro screen with four way masking (demo unit)for the low low price of *only* $17k, down from $45k. For awhile I actually considered trying to haggle and get it for slightly less, and when I started looking at the assembly instructions and in parallel seeing how Somfy motors work, I determined one could be built for maybe $1-2k.

There are so many ways this could be done, and a variety of parts that could be used. I’ve spent a lot of time writing Bluetooth code for microcontrollers and designing custom PCBs for odd projects, I don’t really have any desire to endlessly tinker on the screen, I just want it to work.

To that end, and to hopefully make a path for others who may not have skill or inclination, I want to try to get all of the pieces precut to length, assemble them, buy rollers with a wireless remote, hang them off of the ends and simply plug them in. Somfy has a wireless bridge that will link the rollers to my Grafik Eye QS as well but the remote would work just fine for many. No major wiring or electronics to assemble, just plug in the wireless motors and maybe some remote control programming.

As far as why not a four channel wide track, I just don’t think I need it to be that large. Whatever is used it will need to be hidden with a masking frame, along with the rollers or anything else. There are also weight considerations, and balanced with rigidity. I’m going to try to use a 2x track for the majority.

One could also mount two individual lengths of track together in parallel with just a few mm between them, mount a roller behind, pull masking material through the slot and wrap it 90° to be the CIH mask. Then you still have an outside channel accessible for the CIW mask to slide on top.

So far I’ve put about $600 worth of materials in my shopping cart, representing all of the frame and mounting hardware to hang it off of the wall. Not cheap, I will probably be into it $1200 for a 180” CIH mask when all is done but it will hopefully be a pro grade setup without a lot of tinkering.
MinHeadroom likes this.

Last edited by sor; 01-31-2020 at 08:08 AM.
sor is online now  
post #30 of 86 Old 01-31-2020, 10:43 AM
sor
Senior Member
 
sor's Avatar
 
Join Date: Sep 2005
Location: UT
Posts: 402
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 155 Post(s)
Liked: 157
Well I pulled the trigger on the 8020 order, we will see how it goes. Hopefully we’ll, but it all could be a disaster too! The one thing that makes me a bit nervous is that I don’t know a whole lot about calculating beam deflection, there are numbers regarding the moment of inertia on these materials and I played with it a bit but I have no idea if I’m calculating correctly. The structure should be fairly well supported so it hopefully won’t be an issue.
MinHeadroom likes this.
sor is online now  
Sponsored Links
Advertisement
 
Reply Dedicated Theater Design & Construction

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off