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Discussion Starter · #1 ·
Hey everyone,

Just wanted to share the makings of my latest prop. It's been a while since I actually made my own prop, rather than help out with someone else's display (I live in a condo), so it was fun getting back into the making spirit.

I put this together to take to the Maker Faire in San Mateo, to get the word out about what the Medusa boards can do. If you've never been to a Maker Faire, you owe it to yourself - it's fantastic! The only bummer was, since I had to stay at the display most of the time, I didn't get to see everyone else's stuff.

But I digress......

Here's the display, with a description after the bump
Maker Faire '11 - Animated pirate and treasure chest
View attachment 16585 View attachment 16586

Here's a little description of the characters, and some construction details...

Juan The Skeleton
A Lindberg rack and pinion skull from graveyardskulls.com The R/P mechanism is fantastic. It made for very nimble and accurate moves during the animation. Juan is flaunting the latest in pirate faux leather vests, as designed and constructed by my mother.
View attachment 16579

The Treasure Chest
This started as a great deal I found at the Halloween Club store off of the 5 FWY. For $10, I got a big pre-painted styrofoam chest, that was supposed to velcro itself together, but fell over if you blew on it. Luckily, I didn't care, because I was planning to put a plywood box insde to hold all the electronics and pneumatics. Thanks again, to Mary Ann Zipagang, for helping secure all 400 (!!) shimmering gold coins to the top of the chest.
View attachment 16580

Here's a shot inside the chest, while I was putting it together. This is about half the wiring that ended up being in there. (still missing from the photo are the wires for Juan The Skeleton, and the spot and flood lights). At the bottom, you can see a server power supply I got from All Electronics (.com, if you're not local). I used this to power the whole display (+12, +5 only). At the left you can see both air cylinders, one to 'jump' the chest, and the other to open the lid. At the back, there's a regulator (to control the force of the 'jump') and a flow control valve (to control the speed the lid opens). Each cylinder uses a MAC 3-way valve, switched by a relay.
View attachment 16581

The Lighting
Just beneath the lid are several high-powered LEDs ('0.5W', ~$1/ea from eBay), to light up the gold, the Medusa board, as well as a moving gleam that can be seen at the beginning of the routine. I used small diameter copper tubing to sheath the LEDs, and glued piano wire with JB Quick to the tubing, so I could then aim the LEDs. I don't recco this, though, since the JB Quick didn't hold onto the piano wire well. However, the LEDs did a great job of making the gold glow
View attachment 16582 View attachment 16583

Two frontal lights were used, one to light up the chest (static LED flood from macetech), and another controlled DIY mini-spot, to light up Juan. The mini-spot is something I built out of PVC, and (4) of the aformentioned 0.5W LEDs from eBay. There's a red, green, blue, and a UV LED in the fixture, although, for this display, I only used the red and blue.
View attachment 16584

Also starring Sir Not Appearing in this Film, as the Cannon which did not fire. My father built a beautiful mini-cannon out of wood and PVC, but we ran out of time, and didn't get to hook the smoke, air blast, and LED into the routine. Perhaps in a later video.

For control, I used VSA, an Enttec Pro, and a Medusa DMX board. Here's the channel layout...

Switch outputs
1. Treasure Chest jump
2. Treasure Chest lid
3. [Unused]
4. [Unused]
5. [Unused]
6. [Unused]
7. [Unused]
8. [Unused]

Servo outputs
1. Juan eye Up/Dn
2. Juan eye L/R
3. Juan nod
4. Juan turn
5. Juan tilt
6. Juan jaw
7. Treasure Chest gleam
8. [Unused]

LED outputs
1. Treasure Chest gleam
2. Gold coins amber left
3. Gold coins amber right
4. Medusa spotlight
5. Juan eye red
6. Juan eye green
7. Juan spotlight red
8. Juan spotlight blue

Thanks for reading!
- Hook
 

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This was such a fun exhibit - that picture with the kid's face captures it all.

People stood around and watched the entire sequence a couple of times through. (I know I did!)
 

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Bucky Brain Surgeon
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Your stuff is just so clever. You're a natural I think.

I was working on our coffin yesterday and I got the 12volt linear actuator to work for opening the lid but 2 things. The opening is a little too slow and the wood in the coffin seems to really amplify the sound of the motor in the actuator. I like the speed that your treasure chest opens with. I think you told me about using regulators on pneumatic cylinders to adjust the speed and so I'm thinking I might copy what you did with your treasure chest. If you could tell me what I would need that would be great. The coffin lid is fairly light but I'm sure its heavier than a foam lid and since I'd want to mount it near the hinge, it's going to have to be able to lift what might be a substantial weight. I have no idea how I would determine what components would be suitable.

I was also thinking about trying a 24volt power source for the actuator. That might speed things up but then I have to find a way to mount the servo to isolate the vibration/noise of the motor. Do you think running that motor at 24 volts would wreck it?
 

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Buck,

If you mount the actuator vertical in the chest, you should be able to control the speed easily by moving the lift pivot further or closer the the hinge side. To reduce noise you could mount the actuator on rubber grommets and inserts. What you want to do is find rubber grommets that will fit into the mounting holes of the actuator. Then use an insert, washer and heavy spring to allow you to mount the unit without compressing it against the chest. So the actuator will basically float away from the chest. The springs need to be strong enough to counter any torque that could cause the body of the actuator to touch the chest. For the insert you can use a blind nut and cut off the wood tangs. The washer should fit over the insert from the other side. The spring should be slightly smaller than the washer but large enough that the bolt will not touch. If you use the blind nuts, you can either screw your bolt in from that side and bolt from the rear of the chest, or you can screw from the rear of the chest into the blind nut. In the latter, your bolts need to extend past the blind nut so you cna put a locking nut on as well.
 

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Discussion Starter · #10 ·
Thanks, everyone, for the kudos! :D

Mr. Chicken,
I did stop by their booth, but I was on a warpath, trying to see as much as I could of the show. Didn't stay long. Bummer I didn't get to meet you!

Jeff,
I know... that kid's expression is classic - that's the kinda stuff that makes all the work worth it.

B'Dude,
Thanks! That's quite a compliment, coming from a guy with a display as elaborate as yours! As for my coffin, there were two components in there, to control the type of motion I got. The regulator controls the pressure to both the 'jump' cylinder, and the lid. The pressure will affect both speed and ultimate force, so I used it to set the jumping force. Then, I used a flow control valve (after the regulator, but outputting only to the lid cylinder) to control the speed of the lid opening. The shutting of the lid and the collapse of the chest after a jump were uncontrolled, and based solely on the weight of each.

Voltage doesn't usually kill motors. Too much current can kill them, by melting stuff or demagnetizing the permanent magnets, and too much speed can kill them, by destroying the bearings. As long as you don't have much load on the motor, you probably won't have too much current, and probably won't have a problem ;) The advantage to air control is that you have a much wider range of speed and force you can apply, for a low price.

- Hook
 

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Discussion Starter · #13 ·
halloween71,

Terra just did a great, multi-part writeup on DMX, which included some info on how to 'program' servo moves in VSA. I say it in quotes because using VSA is nowhere near as esoteric as programming code. Once you've got everything wired up, animating the moves is pretty easy. IIRC, I animated the whole display in 2 nights. Although...... more time will always make it look better (wished I'd had that luxury, at the time).

Go download the demo version of VSA, and try it out. You don't need any hardware to see what the software is about, and it's free! :D

- Hook
 

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Hey everyone,

Just wanted to share the makings of my latest prop. It's been a while since I actually made my own prop, rather than help out with someone else's display (I live in a condo), so it was fun getting back into the making spirit.

I put this together to take to the Maker Faire in San Mateo, to get the word out about what the Medusa boards can do. If you've never been to a Maker Faire, you owe it to yourself - it's fantastic! The only bummer was, since I had to stay at the display most of the time, I didn't get to see everyone else's stuff.

But I digress......

Here's the display, with a description after the bump
Maker Faire '11 - Animated pirate and treasure chest
View attachment 16585 View attachment 16586

Here's a little description of the characters, and some construction details...

Juan The Skeleton
A Lindberg rack and pinion skull from graveyardskulls.com The R/P mechanism is fantastic. It made for very nimble and accurate moves during the animation. Juan is flaunting the latest in pirate faux leather vests, as designed and constructed by my mother.
View attachment 16579

The Treasure Chest
This started as a great deal I found at the Halloween Club store off of the 5 FWY. For $10, I got a big pre-painted styrofoam chest, that was supposed to velcro itself together, but fell over if you blew on it. Luckily, I didn't care, because I was planning to put a plywood box insde to hold all the electronics and pneumatics. Thanks again, to Mary Ann Zipagang, for helping secure all 400 (!!) shimmering gold coins to the top of the chest.
View attachment 16580

Here's a shot inside the chest, while I was putting it together. This is about half the wiring that ended up being in there. (still missing from the photo are the wires for Juan The Skeleton, and the spot and flood lights). At the bottom, you can see a server power supply I got from All Electronics (.com, if you're not local). I used this to power the whole display (+12, +5 only). At the left you can see both air cylinders, one to 'jump' the chest, and the other to open the lid. At the back, there's a regulator (to control the force of the 'jump') and a flow control valve (to control the speed the lid opens). Each cylinder uses a MAC 3-way valve, switched by a relay.
View attachment 16581

The Lighting
Just beneath the lid are several high-powered LEDs ('0.5W', ~$1/ea from eBay), to light up the gold, the Medusa board, as well as a moving gleam that can be seen at the beginning of the routine. I used small diameter copper tubing to sheath the LEDs, and glued piano wire with JB Quick to the tubing, so I could then aim the LEDs. I don't recco this, though, since the JB Quick didn't hold onto the piano wire well. However, the LEDs did a great job of making the gold glow
View attachment 16582 View attachment 16583

Two frontal lights were used, one to light up the chest (static LED flood from macetech), and another controlled DIY mini-spot, to light up Juan. The mini-spot is something I built out of PVC, and (4) of the aformentioned 0.5W LEDs from eBay. There's a red, green, blue, and a UV LED in the fixture, although, for this display, I only used the red and blue.
View attachment 16584

Also starring Sir Not Appearing in this Film, as the Cannon which did not fire. My father built a beautiful mini-cannon out of wood and PVC, but we ran out of time, and didn't get to hook the smoke, air blast, and LED into the routine. Perhaps in a later video.

For control, I used VSA, an Enttec Pro, and a Medusa DMX board. Here's the channel layout...

Switch outputs
1. Treasure Chest jump
2. Treasure Chest lid
3. [Unused]
4. [Unused]
5. [Unused]
6. [Unused]
7. [Unused]
8. [Unused]

Servo outputs
1. Juan eye Up/Dn
2. Juan eye L/R
3. Juan nod
4. Juan turn
5. Juan tilt
6. Juan jaw
7. Treasure Chest gleam
8. [Unused]

LED outputs
1. Treasure Chest gleam
2. Gold coins amber left
3. Gold coins amber right
4. Medusa spotlight
5. Juan eye red
6. Juan eye green
7. Juan spotlight red
8. Juan spotlight blue

Thanks for reading!
- Hook

Great work..hey speaking of mini cannons... I received 4 black powder mini cannons from pyrocreations.com They are small in size but can really give out a large bang!! The cannons are actually made by Kennesaw Cannon Company. I also ordered electronic igniters and some fuses. It's not for a prop but an RC Pirate ship that I plan to build from scratch, have it light up, and also fire the cannons wirelessly.
 

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Bucky Brain Surgeon
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Buck,

If you mount the actuator vertical in the chest, you should be able to control the speed easily by moving the lift pivot further or closer the the hinge side. To reduce noise you could mount the actuator on rubber grommets and inserts. What you want to do is find rubber grommets that will fit into the mounting holes of the actuator. Then use an insert, washer and heavy spring to allow you to mount the unit without compressing it against the chest. So the actuator will basically float away from the chest. The springs need to be strong enough to counter any torque that could cause the body of the actuator to touch the chest. For the insert you can use a blind nut and cut off the wood tangs. The washer should fit over the insert from the other side. The spring should be slightly smaller than the washer but large enough that the bolt will not touch. If you use the blind nuts, you can either screw your bolt in from that side and bolt from the rear of the chest, or you can screw from the rear of the chest into the blind nut. In the latter, your bolts need to extend past the blind nut so you cna put a locking nut on as well.
I may actually try that. The only thing is that this actuator is 12" and it takes a long time to fully extend. It would be so cool if there was a way to reposition the micro switches inside of the actuator to get just the amount of movement you need. I could maybe look at an actuator with a shorter throw but then that'd be another $70 or so. I got lost when you talked about "floating away from the chest". I'm trying to picture what you mean. I'm gonna have to look up "wood tangs" and "blind nuts" too I don't know what that means. I'm thinking the grommets I might find at an auto parts store.
 

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Buck

The tangs are the sharp points that the blind nuts have to dig into the wood. Just go to a hardware store and ask for wood blind nuts. You should be able to find grommets there as well.

So does the actuator run it's full throw?
 

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Bucky Brain Surgeon
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Ah! So those are blind nuts! I actually have some of those that I used to repair some office chairs a few years ago.

Yes the actuator runs it's full 12" throw. I took it apart to see how it was constructed and found a nylon track with two micro switches on each end. As the rod winds up or down, there's a slide on the track that turns off the power as it reaches the end of its' travel. When you reverse power polarity to the actuator it will travel in the opposite direction.

At the moment I have the actuator attached to the inside wall of the hinged side of the coffin. I think the location of the base of the actuator is what is causing the amplification of the motor noise. I have a few more ideas for mounting it.
 

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Re the Micro switches. That is interesting. I would like to see the wiring diagram. The reason I ask is because it might be helpful for prop control. So the power to the motor is cut when the limit switch is made. But if the circuit is open to the motor how does reverse polarity get to the motor? Maybe there is a diode that is involved. So when the limit switch is made the circuit changes from a bi polarity circuit to a mono polarity. I never thought of using a diode in a movement limit circuit, but I just realized it might work. NC would be wired straight. NO would have a diode to allow one polarity at each end. Opposite of course. But makes for some interesting ideas for the electric motor crowd. You could have a MITB using a wiper motor and create random movement of the lid. Using two relays with one wired reverse polarity to the motor. One thing that would be tricky is to make sure both relays did not activate at the same time. That would be BAAADDDD !!!! LOL, But with the limit switch with diode option, you could create a limit of travel on both open and close. If one relay was activated longer than the limit point, it would not matter. The lid would just pause at that point until the other relay fired.
 

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Discussion Starter · #19 ·
The way to do what you're talking about, with limit switches, is to use a DPDT relay. Unfortunately, I don't have time to draw a diagram right now, though.

You'd have the two leads of the motor connected to the (2) common terminals of the relay. Then, at the NC terminals, you'd have + and -. And for the NO terminals, you'd have - and +. This will get you bidirectional movement on the motor. BUT, it won't let you shut the motor off....

Then, install two NC limit switches inline with the wiring to the NC and NO terminals on the DPDT relay. Install these at the proper location on the travel of the motor. If everything is correct here, you should be able to flip the DPDT relay, and have the motor move to one extreme, then shut itself off through the use of the limit switch. And even though power to that direction is cut off (through that particular limit switch), the power to drive the motor the other direction is still enabled, because the limit switch on the opposite end is still conducting power to the other throw of the DPDT relay. Flip the relay to the other side, and the actuator should move back.

I know describing wiring with words is terrible. Wish I had more time ATM.

What else I'll say, though, is that presuming you've got a compressor already, using air cylinders is going to be a lot better bang for the buck. Linear actuators are generally a lot more expensive than air cylinders. There is one place where linear actuators would be of serious benefit, and that would be using one as a servo actuator. But that's way more dough even than using just the linear actuator by itself (~$300+ for servo actuator, ~$90 for servoamp).

- Hook

[EDIT] God bless the internet... read all about it, with diagrams, graphics, etc... here.
 

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Most linear actuators do have limit switches on both ends which makes them really easy to use if you can use the actuator in such a way that all you have to do is move it to one end and then back again. However, they also make linear actuators that have potentiometers built in to provide feedback as to the position of the actuator. I used one of these in building a prop that had a talking skull inside a 'crypt'. The actuator raised the torso of the talking skull and in turn raised the lid of the crypt. It certaily does not move as fast as a pneumatic ram but I did not need speed - in fact I wanted it to go slowly as it was mimicing human movement. I used a 'translator' board that effectively turned the actuator into a servo motor that could be controlled by VSA just like a normal servo. I built my own controller but you can buy a complete system with actuator and translator from servocity.com here. I know they are expensive, but mine needed to lift about 25 lbs and it ran for a week straight for 2 seasons and I never touched it after I first put it together. The actuators are built for industrial applications so they are very robust.
 
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