I decided to finally get around to replacing the wires on TRAVIS I so that all FSRs work. I am also slowly working on a duet for both TRAVIS violins, so now is a good time to make sure that both are in tip top shape. I replaced the wires with silicon ribbon wire, so hopefully it won't get damaged as easily as before. It's also black, so it blends in better and is aesthetically pleasing. I wish I could do the same for TRAVIS II, but for that violin I need 16 wires. The most that comes with the silicon wire is 10. I also finally re-printed TRAVIS I's MKR case lid in black filament. I also printed the same clamps as TRAVIS II's design for the FSRs and to hold down the wires away from the strings, so I'm no longer using a clip on the MKR case.
Before I started I tested the ribbon wire with the Lilypad. During this process, the Lilypad died completely and no amount of resetting helps. This makes me sad. I also don't want to spend more money on a new Lilypad since the only one that works is one from China that takes months to ship. RIP original wired prototype. You served well.
Re-soldering was terrifying. I didn't want to replace the softpots yet, because they're still working fine. (although dust is accumulating under them and the added height is making the strings buzz. Maybe I should change them soon anyways...) So I had to remove the strings and place a mat on top of the violin to solder. Taking off all strings of any violin family instrument is scary because usually what happens is the sound post collapses due to the loss of string pressure (guitarists usually fall into this trap when changing violin strings for the first time). However, with a strange twist in fate, that didn't happen when I was working on TRAVIS II. So I thought I would take the chance with this TRAVIS I maintenance, and take it in to Aaron if it did collapse.
Well, it didn't collapse. One disaster averted. The next terrifying thing was soldering so close to wood, and on a wobbly surface. And the pins of the softpots kept moving because I couldn't clamp them down. It was difficult. It took a while. I hope to never repeat the experience. But it's done and TRAVIS I is now looking extra sexy.
"Dream State" is the first piece made for TRAVIS II. It is semi-improvised. Different sound processes were mapped to each of the four strings, as well as different parameters for the visuals.
I re-printed the fingerboard to be as short as possible. I also added an undercurve to the header piece. However, I still found the fingerboard to be slightly too high and asked Aaron to shave off a bit from the ebony piece. He did that, plus added a small piece of wood for support. I found that this not only strengthens the fingerboard, but also makes the violin sound better and cuts out the majority of the buzzing that was happening before on certain notes. Now I am only getting buzzing on first finger, G string (A).
I also shortened the wires and added a clamp to keep the wires down and away from the bow.
Had another mess up with soldering the shield. But I got it! I found that the front end still needs pressure in order to work the best. But the Arduino case is snug enough that it provides that pressure. Also, it’s not quite perfect because sometimes the FSRs are a little jittery when they are at rest, and they should not be like that. However, I can fix that in Max because I was previously having the same problem with the Softpots and the MKR (for some reason the Lilypad was fine).
Despite the buzzing, I moved on to working on the Arduino, because for the purposes of a proof of concept, the fingerboard was done. I discovered that the swiss machine headers I have are slightly different from the ones that are on TRAVIS I. For some reason the connection between the shield and the Arduino is fine when it is tilted to the extreme and does not work when it is sitting flat. I think it will be fine if the male to male headers are turned around.
The ebony piece is attached and the PLA part is taped on with scotch double sided tape. I found that the ebony was a little too tall, so my G string was buzzing when I played forte. I can see when looking at the side that the bottom of the header piece is not flush with the bottom of the ebony piece. I think the fingerboard being flat underneath (without an undercurve) makes the sound a little tinny. Certain notes I’m also getting a strange buzzing. Maybe a wolf tone modulator will help to make it sound warmer?
Pay no mind to my poor intonation...
Shhh... you never saw me practicing in the fablabx!
I tested the strips after sanding them and they barely worked. I then took them out of the fingerboard and flipped them over to test the other side. The un-sanded side still worked fine. So, lesson learnt, to not sand the side of conductive PLA that needs to be conductive! I ended up re-printing all of my strips… again. I also sanded the sides of them so that they can fit into the slots, and that was fine, just as long as I didn’t sand the surface.
Here are the results for the re-printed strips:
I noticed this one is a bit more jittery at the 20k setting at the far nut end.
20k setting, starting at the middle is a bit jittery. Nut end isn’t too bad though.
I finally finished the first ebony method fingerboard! Hopefully I won’t do anything to mess it up…
I made the header holes tighter, so they don’t need glue to stay in. Just need to be extra careful when unplugging them that they don’t get pulled out. I sanded the top so that the strips are flush with the surface.
I did a few things. First was the JST connectors arrived, so I figured out where it should go for the strings. I didn't solder them yet though. Second was even more troubleshooting issues with the strips…
I spent the past week or so focusing on mechanical issues rather than electrical. I’ve been printing lots of strips because of it, but not testing them. Now I think I have figured out a good relationship between the strips and the fingerboard, so I am testing the resistance again.
One problem is that superglue insulates the header. Too much glue and I lose the connection. I think I developed a way to get it right, but only after accidentally messing up the D and A strips. I tried soaking them in rubbing alcohol and in nail polish remover, it didn’t help.
My solution was to first take a soldering iron and press down on the header for about 5 sec so it would sink deeper into the hole. Then I made a cup of hot water and dipped the end into the cup. After that I squeezed the edges so that the header would be wedged in. I added superglue to the outside in order to provide support to the edges. It doesn’t look pretty, but it works.
Then… the above method only worked with the D strip and I ended up ruining all of the headers with superglue anyways...
I adjusted the slot placement and chopped off the bottom half of the fingerboard. I also printed a second piece to hold the header ends. This way I am creating the full length of the fingerboard. I had to completely re-do the design of the strips in order for there to be enough room for them at the nut end. Before they were “I” shaped. Now they are shaped more like how my clamps fit together. I also have to print them with supports because the header end is now flat on the build plate and the rest of the strip is in the air. Not the most ideal way to print, but my tests from a long time ago proved that they can't be printed sideways without ruining the rails that keep the strip in place.
These pictures are taken before the ebony base was ready. I just placed the prints on for the sake of measuring.
Since printing the entire fingerboard was not working, Aaron had an idea to help make it stronger. I print only the top portion of the fingerboard, and he makes an ebony base. This means that the fingerboard will not have the under-curve, but at least it should be strong enough. We'll see how it affects the sound. This was his drawing.
I’ve been printing parts for the Arduino case. The lipo battery I have is slightly smaller than the last one, so I had to make some adjustments to the dimensions of its box. The first time I printed it, it was a little bit too small. But I got it on the second try. There was something interesting I noticed about the clamps that I printed. They were all from the same file, but their lengths were ever so slightly different. I then realized that it must have had to do with which way they were oriented while printing, and gravity was affecting it.
Even though the last fingerboard print wasn’t working, I put it on my violin in order to see how the outer dimensions fit, and how the slots line up under the strings. It was a little too tall on the nut end. The two outer slots should be moved over a bit. However, I discovered an even bigger problem: the fingerboard bends when playing in the high positions.
I made the length of the fingerboard slightly shorter in order to accommodate the smaller build plate of the Ultimaker. It curves a bit. Another problem is that 3 out of four strips don’t fit. It kind of looks like a Wolverine claw. I’m not sure why because they were all modelled with the same dimensions. Because of how the model curves on top of the fingerboard, it’s not perfectly smooth.
Welcome to the TRAVIS blog!
If you would like to see a summary of my work, please click here.