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 Forum index » DIY Hardware and Software » Les Hall's Projects including eChucK
Robotica
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CreatorLes



Joined: Oct 05, 2014
Posts: 84
Location: San Antonio TX USA

PostPosted: Wed May 13, 2015 9:37 am    Post subject: Robotica
Subject description: A Music Enclosure and Project
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Hey all,

This morning I had a creativity moment and came up with the attitude shape, which I printed in carbon fiber PLA filament. There are a lot of things that can be done with this shape.

What I am planning to do is simple, very simple. I will make a resistive controller out of it by printing in conductive carbon fiber filament. The resistivity of this material is 1200 Ohm-cm, which means that you tend to get resistances in the 100k and MegOhm ranges, perfect for low-power Lunette circuits.

I will design the print to be paused and then received insert consisting of a stereo audio jack with three wires soldered to it. This insert will be pre-formed on a jig such that the print may be paused, the insert placed in it, then the print resumed and run to completion. The ground, tip (left) and ring (right) contacts will connect to the three wires, which will travel with their insulation intact to the three corners of this device where they will make contact with the print.

If all goes well, and I stick to the project, the result will be a controller that can be worked into a circuit in a variety of ways. Alternatively the wires can be sent to contact pads internally and an insulating material used for the print.

In the first case, moving your hand in physical contact with the conductive carbon fiber shape will alter the resistances between the three terminals, making your fingers provide shorting resistance to the shape, varying it's terminal resistance.

In the second case it may be driven as a capacitive touch sensor so that placing your fingers on or near the shape will change the music that is created by a capacitive touch sensor circuit.

In either case, example circuits will be provided or sold (assuming I stick with this project - time will tell).

If you think this is cool or would like to suggest an alternate shape, please advise, thanks.

Les


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Robotica - a music project enclosure
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PHOBoS



Joined: Jan 14, 2010
Posts: 4540
Location: Moon Base
Audio files: 633

PostPosted: Wed May 13, 2015 2:38 pm    Post subject: Reply with quote  Mark this post and the followings unread

sounds interesting, have you tried the pausing inserting something before ?
as for shapes, would a sphere with varying thickness work ?

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CreatorLes



Joined: Oct 05, 2014
Posts: 84
Location: San Antonio TX USA

PostPosted: Wed May 13, 2015 8:12 pm    Post subject: Reply with quote  Mark this post and the followings unread

PHOBoS wrote:
sounds interesting, have you tried the pausing inserting something before ?
as for shapes, would a sphere with varying thickness work ?


These are interesting questions, PHOBos. I have not tried the pausing method before and upon reflection I am a bit concerned about doing it. Certainly the notion of a fully sealed device is appealing, however the risk of a wasted print due to nozzle leakage is a genuine concern. I'd rather avoid that part of the equation. Besides, that way the part becomes non-serviceable.

Before I get to the sphere, I'll interject that I thought of a great external treatment to turn this and other flat-ish shapes into controllers. I happen to have, from Adafruit, a kit for making FSRs (Force Sensitive Resistors). I thought I would make a pair of these and run the wires through a strain relief then onto a circuit board. That would give two variable resistors on a durable enough surface though not commercially viable, certainly quite usable for hobbyist purposes.

Now for the sphere. Yes, I can design a sphere with varying thickness and print it in flexible filament. I just happen to have bought a replacement extruder kit that comes with all the hardware, gears and such to print and build your own experimental extruder that prints flexible filament. So it's a project to get to that point. Once there, however, I can definitely print flex.

Now in addition to being flexible, your sphere must vary electrically. I happen to have, also from Adafruit, some flexible rubber chord. This material is 1/8" in diameter and I just measured it to have resistance of about 50 ohms per inch, varying to 100 Ohms when stretched by 30% or so of it's length. So a doubling of resistance with a bit of flex. The Sphere could be designed to be not solid but open aired with infill or webbing inside of it and channels to accept this chord, then the chord could be crimped at it's ends and sensed by the circuit with a current source or voltage divider or some such circuit. The low resistance of 100 Ohms could be brought up to a few kOhms by using a foot or so of the material in a few passes through a three inch sphere. The sphere would have to be flat on the bottom to be printed, but that's good to keep it from rolling away!

So there you go, yes and yes are your answers, PHOBos! Shall we collaborate?

Les

Last edited by CreatorLes on Wed May 13, 2015 11:30 pm; edited 1 time in total
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CreatorLes



Joined: Oct 05, 2014
Posts: 84
Location: San Antonio TX USA

PostPosted: Wed May 13, 2015 11:24 pm    Post subject: Reply with quote  Mark this post and the followings unread

Actually PHOBos, if you are interested, I'd be happy to send you one or more prints for free including free shipping. I have the little priority mail boxes and plenty of postage that my Mom got for me before she went galavanting around the world again on a cruise ship, so it won't cost me a cent.

What I can send you is either the shape on the right, which is hollow inside and has an opening running down the center plus slightly lower quality of print, and the one on the left which is solid and higher quality.

My only stipulation would be that you do something cool with them and post about them here - no big deal as you do that all the time!

I'm happy to do this to help get the ball rolling in the use of 3D printing at electro-music. What do you say?

Les

p.s. I can make other prints too, if it's not overly time consuming (hours not weeks), like a favorite logo or a small project enclosure - as long as it fits in a small flat-shaped Priority Mail box.


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Robotica x 2: original on left, hollow with opening on right
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RingMad



Joined: Jan 15, 2011
Posts: 384
Location: Montreal, Canada
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PostPosted: Sat May 16, 2015 4:18 am    Post subject: Re: Robotica
Subject description: A Music Enclosure and Project
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CreatorLes wrote:
moving your hand in physical contact with the conductive carbon fiber shape will alter the resistances between the three terminals, making your fingers provide shorting resistance to the shape, varying it's terminal resistance.

Forgive my ignorance, but how does that work? I've built ribbon controllers using resistive videotape, and if one wires it as a variable resistor, there's a terminal at one end of the tape, and another on a conductor wire. Pressing your finger makes the tape and conductor contact, thus completing the circuit. If I'm understanding correctly, what you are describing works without the conductor part?

Another question I have is how durable is the conductive carbon fiber filament? One problem I had with my videotape-with-guitar-string-suspended-above style controller is that it wasn't long before the resistive material started to degrade.

.:James:.
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CreatorLes



Joined: Oct 05, 2014
Posts: 84
Location: San Antonio TX USA

PostPosted: Sun May 17, 2015 11:42 am    Post subject: Re: Robotica
Subject description: A Music Enclosure and Project
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RingMad wrote:
CreatorLes wrote:
moving your hand in physical contact with the conductive carbon fiber shape will alter the resistances between the three terminals, making your fingers provide shorting resistance to the shape, varying it's terminal resistance.

Forgive my ignorance, but how does that work? I've built ribbon controllers using resistive videotape, and if one wires it as a variable resistor, there's a terminal at one end of the tape, and another on a conductor wire. Pressing your finger makes the tape and conductor contact, thus completing the circuit. If I'm understanding correctly, what you are describing works without the conductor part?

Another question I have is how durable is the conductive carbon fiber filament? One problem I had with my videotape-with-guitar-string-suspended-above style controller is that it wasn't long before the resistive material started to degrade.

.:James:.



Unfortunately carbon fiber filament, which used to be conductive with 1200 Ohm-cm is no longer conductive. I just measured it and there was zero conductivity in the filament. This is disappointing to me but I guess it is a result of process improvement of the filament supplier.

As far as its durability, it is extremely durable as it is stiff and strong but inflexible. I have a small carbon fiber object to a large man with a strong grip, stronger than mine and asked him to break it. He tried and could not. Neither could I. This object was long and thin (a Christian cross), so I'm surprised it was that strong. Then the nurse said something about polymer bonding and I realized it's more than just mixing the fiber together with the processed corn oil polymers.

So that controller type is out, but I do have some carbon fiber so if anyone has some guitar mount or some other thing that is not strong enough, give a holler.

Les
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CreatorLes



Joined: Oct 05, 2014
Posts: 84
Location: San Antonio TX USA

PostPosted: Wed May 20, 2015 4:24 am    Post subject: Reply with quote  Mark this post and the followings unread

I have figured out how to do capacitive sensing with arduino. Now I can make a shape that eencloses an Arduino UNO board and sends data into the pc as string information to be decoded and converted to MIDI by a processing program, for example.

Les
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elmegil



Joined: Mar 20, 2012
Posts: 2111
Location: Chicago
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PostPosted: Wed May 20, 2015 7:22 am    Post subject: Reply with quote  Mark this post and the followings unread

Excellent Smile
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CreatorLes



Joined: Oct 05, 2014
Posts: 84
Location: San Antonio TX USA

PostPosted: Wed May 20, 2015 10:33 am    Post subject: Reply with quote  Mark this post and the followings unread

elmegil wrote:
Excellent Smile


Yeah! Coolness and I have working code now, minus the MIDI part. If you have an Arduino board you can run this stuff as soon as I post it. Plan to add MIDI first and maybe USB channel select also.

There is no need to have a 3D printed shape to make this project, just an Arduino board, a USB cable, some 24 ga. wire, and two resistors of 1MEG Ohm or greater value.

Les
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CreatorLes



Joined: Oct 05, 2014
Posts: 84
Location: San Antonio TX USA

PostPosted: Wed May 20, 2015 10:07 pm    Post subject: Reply with quote  Mark this post and the followings unread

The Capacitive Sensor project is shaping up, here is the current code:

Arduino Code: http://pastebin.com/3miY7y1g

Processing Code: http://pastebin.com/jCWWDCbw

The video I made for you to use the above code will be here when it's done uploading:

https://www.youtube.com/watch?v=DV8HgIiaw14&feature=youtu.be

Les
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CreatorLes



Joined: Oct 05, 2014
Posts: 84
Location: San Antonio TX USA

PostPosted: Thu May 21, 2015 1:07 am    Post subject: Reply with quote  Mark this post and the followings unread

OK, I got some sleep, the night is young (well, middle aged Smile and the printer is printing a big job so let me take a few moments to comment about the project in text form.

First, the price of entry for this project is an Arduino Uno R3 board. That's $25 new. Maybe you can scrounge for cheaper or use a less expensive variant of Arduino - that's your trip, not mine. Once you have an UNO or other Arduino you have the basis for a bunch-o-projects including this one. You can make your own sense-o-matic gizmo with 10 or 20 sensors hanging off of it, or just do the simpler two-sensor project described here.

These sensors can create one square wave tone() (frequency adjustable) wave or a couple of analogWrite(PWM) waves, or you can bit bang a low frequency output, all suitable for Lunette or other digital use. There is no analog output barring an R2R ladder or DAC of your own doing. OR you can do what I've done here and send a stream of samples to the computer over it's USB interface. Or you can do any combination of the above. And I'm here to guide you in the process for what that's worth...

I have written one Arduino and one Processing program to cover both ends of the process. These programs are mainly pieced together from two examples each - I'm not proud enough to code from scratch. In fact, I'll do it again and add MIDI and OSC to the Processing program so you can, with minimal fuss, use your existing software with a Capacitive Sensor that you build yourself.

I've given some thought to the 3D printing of cases, which is the only profit angle on this for me. I can figure out some "hands on" hourly rates for doing stuff like setting up the printer, babysitting it, doing design, etc. and you can plan my actions from afar. Of course, you know me, I'll work a lot more time than you pay for and not charge much, being more than fair and erring on the side of low cost because this is Hobby stuff after all. But yeah, if you you want a snazzy custom cat it's a few bucks. As few as possible, deal?

But you don't need to pay me a dime and I'll still make sure you have a great project to accomplish! So where were we... OK, I designed the Arduino project to drive a speaker (optional and removed once we get going) so that you can debug what is going on in it's little Arduino brain. If you hear notes at a rate of about 1/3 of a second each, then it's in the init mode where the Arduino is waiting for the computer to establish first contact. If it's a faster, nearly continuous sound, first contact has been made by the computer and the problem lies elsewhere (if there is a problem, that is). You got a problem? What's your problem man! lol

Also please be aware of two kinks (i didn't say this project would be kinky but it is, a little bit). Kink number one is that you need to download and install the Capacitive Sense library into your Arduino directory. I'll explain that process (which is easy) if anyone needs such.

Kink B, as it were, is that Processing is way too stupid to keep track of USB ports (well hmm, just thought of a way to automate it hmmm.... more to follow), so for now at least you must SET THE PORT NUMBER YOURSELF. This means looking at the program's text output in the Processing IDE"s console at the bottom and reading the ports, counting from the top one (starting at zero of course), selecting your port, and changing the port variable at the very tippy top of the program to be that number. There, that wasn't so kinky was it?

Aight, aside from that the project will be ONLY AS KINKY AS YOU PERSONALLY WANT IT TO BE. k, 'buff of that joke. That should do for an intro with a bit of an overview, a touch of the biz stuff, and some important details that will help you get through the tough parts in the trenches. Now go forth and conquier Capacitive Sensing - Chaaaaarge!

Les
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CreatorLes



Joined: Oct 05, 2014
Posts: 84
Location: San Antonio TX USA

PostPosted: Thu May 21, 2015 1:44 am    Post subject: Reply with quote  Mark this post and the followings unread

Here is a photo of a standard 3D printed project box, printed in glow-in-the-dark filament.

Les


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Arduino Box Bottom holding Arduino, no screws
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RingMad



Joined: Jan 15, 2011
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PostPosted: Thu May 21, 2015 10:54 am    Post subject: Reply with quote  Mark this post and the followings unread

Glow-in-the-dark filament? Cool! I'll have to think of something for that.

.: James :.
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CreatorLes



Joined: Oct 05, 2014
Posts: 84
Location: San Antonio TX USA

PostPosted: Thu May 21, 2015 1:24 pm    Post subject: Reply with quote  Mark this post and the followings unread

RingMad wrote:
Glow-in-the-dark filament? Cool! I'll have to think of something for that.

.: James :.


Sure James, just let me know. The stuff I have is pretty strong and it prints fairly well (ColorFabb GlowFill). There are all sorts of materials out there - the metals and the woods, brick and just about anything you can grind small enough to put into a filament!

Les
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CreatorLes



Joined: Oct 05, 2014
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Location: San Antonio TX USA

PostPosted: Fri May 22, 2015 12:34 am    Post subject: Reply with quote  Mark this post and the followings unread

Aha! I got to looking around on the Arduino Playground, which I'd highly recommend doing if you're into Arduino, and I found code for how to do implement OSC directly in the Arduino itself! This way no external quirky program is required (and Processing is quite finicky about the serial ports).

Look here for how to do it: http://cnmat.berkeley.edu/oscuino

Les
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CreatorLes



Joined: Oct 05, 2014
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PostPosted: Fri May 22, 2015 4:28 am    Post subject: Reply with quote  Mark this post and the followings unread

well i got the OSC working, but problem is the dang ChucK won't listen to the serial port to get it's OSC fix. Oh well, apparently MAX/MSP does. Maybe other stuff does too. Can always get a WiFi card and send it that way.

Les
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