Author Topic: Looking for Help with Making Flowers Go In and Out of a Flexible Tube  (Read 684 times)

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Offline MystarliteTopic starter

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Hello. I've been trying to find information on how to make this idea work and have posted this on facebook and other sites but haven't had much help yet.

I would like to figure out how to make 6 flowers go in and out of a flexible tube. I was thinking of having short tubes that the ends of actuators would push out of with the flowers attached to the ends. Batteries i would fit into the handle somehow.

This is what i would like to make with the red flowers on the vine.

I would like to keep the timing of the flowers close to the animation.

It was suggested to me on a facebook page that i could use muscle wire as well. I'm not sure about solenoids either.

I would probably need a way to ensure that the flowers open as well when pushed out of the tubes and not just flop to the bottom due to gravity.

Currently i am researching how i would go about doing this. I won't be able to start experimenting until i get a job and have money to spend. I would very much like for this as well as the whole costume to be completed in time for the convention i plan on attending in November.

Thankies!

Offline Duane Degn

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Do you want all the flowers to open at once?

My first guess at a solution to your problem would be to use control rods for model airplane control surfaces like these.

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXFU90&P=7

One end would be connected to the base of the flower and the other end connected to a hobby servo.

I've listed some of the servos I like to use in post #10 of the thread below.

http://forums.parallax.com/showthread.php/135706-Index-Test?p=1049903&viewfull=1#post1049903

The list of servos is near the top of post #10, under "Servo Stuff". The servos in the list are generally pretty cheap and there are many higher quality servos available but at a higher price.

The servo would push and pull one or more of the control rods. If you don't need independent control of each flower you could have the servo move multiple control rods. It might be cool to have independent control of each flower.

Depending on the materials used for your flowers, you might be able to get by with the the little blue "HXT900" servos which are pretty cheap. One thing that's nice about the HXT900 servos is they have a full 180 degree throw.

You can see the 180 degree movement in the video embedded in post #1 of this thread (jump to 3:15).

http://forums.parallax.com/showthread.php/137197-QuickStart-Servo-Tester

The 180 degree movement isn't really very important since you can magnify any servo movement by increasing the size of the lever arm. The longer the lever arm, the more torque will be required to move the load at the end of the arm.

Will there be room at one end of the tube to mount servos? If not, your problem becomes much more difficult to solve.

Offline MystarliteTopic starter

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Thankies for the reply! I'm about to head out for dinner so will check out the links when i get back.

The flowers i want to open one at a time one after the other, then close in the same order one at a time once they're all open. With my very limited knowledge of how stuff works i thought about having pistons pushing them in and out but they looked to be connected and rotate along a solid section. The servos idea may work.

Laying in bed earlier i came across the idea of using a coil spring that i could mount whatever i use to on the inside, then cover with a green cloth tube and then wrap that around the bow. I'd poke a hole for the flowers to protrude a bit at the lowest setting. The bow will be over 5' long and i'm thinking the spring coil would be about 1" in diametre.

For the flowers, i don't know if having a conic spring would work to spread them open and pull them back in or if they'd get caught on the outside of the hole. I thought about an umbrella type opening but don't want anything visible on the outside of the flowers. I haven't decided on what i'd make the flowers out of. Perhaps white cloth or silk painted or if i can get them dyed consistently, then try that. Or just buy fake flowers to use that are as close to how they look as i can find.

Since i'd be taking the whole thing in a suitcase and not wanting to pay about $200 for oversized luggage either way i will see if i can make this in parts. I'd probably need connectors so i can plug them in when assembled. Hollow out the handle of the bow, put a hole where the wires would go through to the coil springs and have a battery mounted in there as well. Maybe a sliding cover or something if i can minimize seams or other visual distractions if that makes sense.

Offline Duane Degn

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I'm not sure about your spring idea. How would you keep if from getting bent out of shape? Could the coils get in the way of the inner workings? I'd think a plastic tube would work better and be easier to position where you want it.

I'd think the little HXT900 servo would be strong enough to push and pull your flowers. It may be possible to hide the servos inside the bow and just have the thin control rod pass from the bow to the tube with flowers.

Another option would be to have half of the servos at either end of the the tube. I'd think it should be possible for the servo to pull on a control rod which would be joined with another rod so the pulling of the one rod would cause the flower to be pushed out. Think of a wire bent in a "V" shape with one side of the "V" shorter than the other. The flower would be connected to the short end of the "V" and the servo to the long end. When the servo pulls on the long end the short end also moves up pushing the flower from the hole. This would allow you to divide up where the servos are positioned.

You mention using a piston to push the flowers. What's powering the piston? I doubt you want compressed air or CO2 to power pneumatic cylinders. Memory wire has very limited travel and requires a lot of current. If you can find a place to hide the little servos, I think they'd be your easiest method of moving the flowers.

Since you want the flowers to come out one at a time, you'll need a separate servo for each flower. It's not a big deal for a microcontroller to independently control multiple servos. You can even control how fast the servo moves throughout its travel.

Here's a demo I made to drive 32 servos with a Propeller chip. If you skip to about one minute into the video, you can see how each servo is moving independently and how the speed of travel can be easily controlled. It's easier to see the movement in the large black servos, but I think the small blue servos would be the ones to use in this application.

QuickStartControlling32Servos120129.AVI


Have you ever used Polymorph (aka ShapeLoc)?

https://www.sparkfun.com/products/10950

It's great stuff. I think it would work well to give your flowers their desired shape. You could add a rod or strip of Polymorph to each pedal of the flower. The Polymorph can easily be bent out of shape (while flowers are inside tube) but then it returns to it's original shape very quickly once the bending pressure is released (pushed out of tube). You could experiment with different sizes of pedal reinforcement to get the desired springiness to your flowers.

I'm thinking a strip of Polymorph about 1/16" in diameter but squished flat a bit and curved to the desired shape of the petal to act as a type of backbone to each petal. Apparently Polymorph can be colored so you could have it match the color of your flowers. There's a link on the Polymorph product page to intructions on how to color it.

Offline MystarliteTopic starter

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I've never used anything but paper really, but i probably did use some more stuff in grade school tech class. That video is kind of like what i want to accomplish! If the servos could stop halfway until all 6 are halfway, then continue and stop until they're all stopped, then start again from the top down, a one way wave with the flowers opening and closing. Or maybe just use servos that go 90 degrees.

I was doodling trying to figure out how i would imagine how this would look inside the tube. I was thinking using a long length of spring but have spent a while trying to find anything close to the length i want to no avail. I've side tracked to looking up coil guns and ironing your own PCBs. The bow itself will be fairly narrow except for the handle part where i plan on housing the batteries and controller.

The piston thing i mentioned i was referring to was basically having a solid cylinder being pushed up and down a hollow cylinder, kind of like in the pic i'm attaching but using a servo.

Yay, found an animation: http://www.grc.nasa.gov/WWW/k-12/airplane/powert.html. The flowers would be attached to the ends of the gray part that gets pushed out of the blue, with a bit of the flowers sticking out so it doesn't go in the hole completely. The vine isn't straight so i wouldn't be able to have 6 linked in such a way and that's when i started thinking of having separate mechanisms for each.

The spring was so that i could tie the servos or otherwise attach them to before covering the entire thing with a cloth tube. I'm not sure how i would go about placing stuff inside a plastic tube unless i cut pieces away. I'm thinking that i would have 2 sections of tubing with 3 servos each, each one having a connector at the end that i can plug into the microcontroller (i'd have a hole near the handle of the bow where the vine meets the bow to pass the connectors through). If i can make the bow 3 pieces, and have 2 sections of tubing with internal servos, then hopefully i can fit them all into my suitcase.  ;D

Thankies for all the links! Now i'm probably too excited to go sleep with my plans looking to be more feasible than when i was trying to figure out the hows.

Maybe a plastic tube that's soft enough to wrap around the bow would work as i can still cover that with a cloth tube. I can glue the small cylinders to hold the flowers and cylinders to it, then make the corresponding holes in the cloth.

Ideally i would want to fashion the bow from one piece of wood but the drive down to the convention centre is 36 hours straight according to Google maps.

Offline Duane Degn

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That video is kind of like what i want to accomplish! If the servos could stop halfway until all 6 are halfway, then continue and stop until they're all stopped, then start again from the top down, a one way wave with the flowers opening and closing. Or maybe just use servos that go 90 degrees.


The servos can be moved in any order and any amounts (within their physical limitations) and at any speed desired. That part is relatively easy if you have the software. I think the code I used to control the 32 servo could easily be modified for your project. I think I posted the code I used to the Parallax forum. I bet you could talk me into modifying it a bit to match your needs.

I was doodling trying to figure out how i would imagine how this would look inside the tube. I was thinking using a long length of spring but have spent a while trying to find anything close to the length i want to no avail. I've side tracked to looking up coil guns and ironing your own PCBs. The bow itself will be fairly narrow except for the handle part where i plan on housing the batteries and controller.


It's not hard to get side tracked researching this stuff. There a lots of really cool projects out there. I'd strongly suggest not worrying about making your own PCBs. There are too many inexpensive online fab houses to do this for you. OSHPark.com is my current favorite. If you want to make custom PCBs (you don't need to for this project) get the free version of DipTrace and use it to submit boards to OSH Park. It does take them a few weeks but they make really nice boards.

The piston thing i mentioned i was referring to was basically having a solid cylinder being pushed up and down a hollow cylinder, kind of like in the pic i'm attaching but using a servo.

Yay, found an animation: http://www.grc.nasa.gov/WWW/k-12/airplane/powert.html. The flowers would be attached to the ends of the gray part that gets pushed out of the blue, with a bit of the flowers sticking out so it doesn't go in the hole completely. The vine isn't straight so i wouldn't be able to have 6 linked in such a way and that's when i started thinking of having separate mechanisms for each.


I don't think you understand the way the Gold-N-Rod push rods I linked to earlier work. They are a piston but a very narrow piston. If you look at the picture in the link you'll see two colors of plastic red and yellow. The servo pushes and pulls the red plastic rod back and forth inside the yellow outer tube. As long as the yellow tube is secured, the movement imparted to one end of the red rod is transmitted to the other end of the control rod.

They use these in radio controlled airplanes. The servo moving the various control surfaces on a RC airplane are often several feet from the part being moved. This lets you move your servos to a more convenient location instead of needing them right next to the flower to be deployed. You'd still want a tube large enough to hold your flower on the one end, but several of these control rods can be feed up the flexible tube holding the flowers. The little blue servos are likely a bit too large to fit directly behind a flower as you have illustrated. Using control rods, you can move the servo pretty much anywhere you want them.

The spring was so that i could tie the servos or otherwise attach them to before covering the entire thing with a cloth tube. I'm not sure how i would go about placing stuff inside a plastic tube unless i cut pieces away. I'm thinking that i would have 2 sections of tubing with 3 servos each, each one having a connector at the end that i can plug into the microcontroller (i'd have a hole near the handle of the bow where the vine meets the bow to pass the connectors through). If i can make the bow 3 pieces, and have 2 sections of tubing with internal servos, then hopefully i can fit them all into my suitcase.  ;D

Thankies for all the links! Now i'm probably too excited to go sleep with my plans looking to be more feasible than when i was trying to figure out the hows.

Maybe a plastic tube that's soft enough to wrap around the bow would work as i can still cover that with a cloth tube. I can glue the small cylinders to hold the flowers and cylinders to it, then make the corresponding holes in the cloth.


You'd be amazed at how many different types of plastic tubes are made. I'm sure there's something flexible enough for your needs. You may need to cut slits into the tube in order to mount the smaller flower tubes inside. You'll also need to secure the outer tube of the control rod to the flexible tube (the control rods are reasonably flexible themselves).

There are lots of different microcontrollers available. My personal favorite is the Propeller chip. I think there are lots of microcontrollers that could easily handle the task of driving multiple servos.

The program I wrote to drive the 32 servos wouldn't work on other microcontrollers so if you want to you the software I've written, you'd need use a Propeller chip as your controller.

If you go with the Propeller chip, you ought to see if a QuickStart board would be small enough for your project. There are smaller Propeller boards available if the QuickStart is too big.

Here's link to my cheap bot which uses a QuickStart for a controller. Hopefully you can get a sense for its size from some of the photos.

http://forums.parallax.com/showthread.php/145826-Cheap-Bot-A-Possible-BSA-Robotics-Merit-Badge-Robot

I like using the QuickStart for projects whenever possible since they are so inexpensive ($25) and can be powered by the same USB connection used to program them. (Don't try to power the servos from the same USB connection.)

SparkFun sells a smaller Propeller board, but it requires a extra parts to program it and it wasn't really designed very well (it doesn't have bypass caps where it should).

https://www.sparkfun.com/products/11525

If you want a small Propeller board like the SparkFun one, I could help you find one.

Offline MystarliteTopic starter

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I've been busy trying to figure out other parts of my costume planning taking screen shots from a model viewing program and then was looking at tutorials for Worbla and other crafting stuff. lol

If the Gold-N-Rods were basically an extension of the servo arm, then that would work. I could keep more of the flower inside the tube and then they'd be bigger when expanded. I tried to find a video of a Gold-N-Rod and saw some pics, then video of an RC helicopter. Now i'm getting sidetracked again. So many interesting things to do in life, yet so little time. Would the Gold-N-Rods be able to push about 1" out? I could attach the flowers to the end of those maybe and then not have to worry about figuring out other tubes to run perpendicular to the surface of the vine tube to contain the flowers.

I agree with not having to make a custom PCB for this, even though i like to do a lot of things myself if i can. I don't need anything too fancy or expensive - just something that can control 6 servos moving them all one after the other and waiting for that action to complete before moving them all again one after the other taking the flowers back down. :) This will probably only be used for a couple of days most likely or whenever i feel like playing around with it. Maybe i'll even reuse it at a future convention as well.

I've been looking at some robotics tutorials and they mention having a separate battery for the servos. I don't know if that means one battery to power all six servos separate from the microcontroller or if that means one battery each.

I was hoping i could just go into a store and see a bunch of plastic tubing or spring coils vertical against the wall like how hardware stores have their copper pipes of various sizes on display.

Looking at the bow again i'm thinking i could hollow out the handle from the front to hide the electronics in and then maybe use velcro to secure the front fascia or something. I haven't thought that far yet and would just like to start with the mechanisms first. The animation is hard to drag trying to view at a certain angle when dragging moves the animation in 3 directions.

I'm going to bed and then hope to get some cleaning done and find a job so i can pay for this project. Then once i have all that taken care of, i can start looking forward to saving up and moving out. One step at a time, though it seems some steps are long overdue.

Thankies again for the help! Not sure what stores i can window shop at for flexible plastic tubing that i could use for the vine portion but at least now i have an idea of how to make the flower parts work. :)

Oh, i've come across a company that ships luggage to one's destination beforehand that has had some good reviews so i may be able to make my bow in as few pieces as i can after all!

If i hollow out the handle and use a fabric flap or something that only covers the hollowed area, i could just attach that with velcro if i can somehow secure one end of the flap and have it blend in with the solid section of the bow so as to not leave a visible seam... but alas, i should get some sleep.

 


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