jwilzewske: sugru

Thursday, December 15, 2011

Making an Ergonomic Holder for eReader Tablets for Piano

M y wife gave me a Samsung Galaxy Tab 10.1 Android tablet for my birthday. I use it for lots of things, but one of its best purposes is as a music reader on our piano.

A irTurn’s Bluetooth-based BT-105 is out--it has many nice, new features.

F or the BT-105, I've used an inexpensive Levenger Dovetail bookstand as a cradle, accessorized with a bit of Sugru® silicone to keep the tablet or the cradle from moving around with the vibration from vigorous playing/pedaling. I use that mostly with our MIDI keyboard.

B ut I still like and use my original AT-104 with its proprietary RF communication between the pedal transmitter and the USB dongle receiver. For one thing, there are no long-range Bluetooth interference/security issues with the AT-104.

T he 1280x800 pixel resolution of the 10.1-inch Widescreen HD WXGA TFT on the Galaxy is noticeably better than the 1024x768 resolution of the iPad 2’s 9.7-inch screen. (The screen on the Samsung tab has a 16:9 aspect ratio, compared to 4:3 on the iPad 2. In the landscape orientation, which is how I position the tablet on the piano music stand, the Galaxy display is only 4% more pixels vertically, but it’s got 25% more res than the iPad 2 horizontally.)

S o if I’m going to stick with my AT-104 AirTurn, then I need to get the USB receiver dongle attached to the Galaxy Tab, and the USB port is at middle of the bottom edge of the tablet. (I could rotate the Tab 180-degrees to be upside-down, so the USB port is on top. But then I’d have an unsightly dongle or pigtail cable coming out up there.)

T he Samsung USB adapter dongle is okay, but it sticks out 3cm beyond the edge of the tablet, and a male USB connector terminating a typical cable-end sticks out 5cm beyond that. You need some way to elevate the tablet about 10cm for the short male-to-female USB passthru/extender cable to the AirTurn Dongle to connect to the Samsung USB dongle.

E levating the tablet that much is actually an improvement in terms of good visual ergonomics. But you need to keep the tablet secure and level in that position.

A nd there’s another issue—which is the same as the issue that's affected the usability of laptop-based music eReaders for pianists: the front-to-back depth. It may be too deep for some piano music stands. And it’s definitely too deep for harpsichord or organ music stands. Or the rail on the music stand that is fine for 60 gm of paper sheetmusic is too wimpy for a shiny, slippery tablet that weighs 600 gm. There is a significant risk that the tablet will shimmy its way to a bad fall.

A further issue for me, at least, is the visually small form-factor of the tablet--specifically, the fact that the active display area of the 10.1-inch screen comes so close to the edge of the device—makes me want to have slightly wider “margins” framing the visual field that I’m looking at. With the tablet on the Dovetail bookstand, the “near-far” field at the left-hand and right-hand edge of the displayed music interferes with my eyes’ focus. Maybe that is not an issue for you, but it is for me.

S o I cut a 12x14-inch piece of black 3/16-inch Delrin acetal, put some 1/2-inch Delrin brackets on it with Sugru® to cushion them (see photo). You slide the tablet into the lower brackets and press the top edge in past the pan-head “crowns” of the 3 Sugru® bumpers--each one is about 1 mL of Sugru® that is molded to stand proud of the 5/16-inch hole by about 0.03-inch. The Sugru® is just the right Shore-A/durometer hardness to “give” just a little as the tablet edge moves inward and seats flat against the acetal sheet. The mechanical “detent” of the Sugru® is just enough to hold the tablet securely in place but still allow the tablet to be easily plucked out again with gentle finger force.

M y kluged black acetal stand leaves a nice visual margin all around, similar to the whitespace from the staves to the edges of normal sheetmusic paper, in the same focal plane as the image on the tablet. It makes it easier to read the Tab’s display, and it’s compatible with any piano, organ, harpsichord, etc., including ones that have only a tiny, narrow rail/groove for music to stand up in.

H ugh Sung’s Airturn site has plenty of nice stands and brackets to hold tablets and laptops on various types of mic stands or other uprights. Those are great for string players, wind instruments, singers, and other kinds of musicians. But if you’re a pianist and you’ve done ‘home-brew’ things yourself, to enhance the mounting of your tablet on your piano's music stand, please leave a comment below or email me!

Sunday, December 5, 2010

Prepared Piano: Subtle Effects by Hacking DIY Nocks with Sugru® Silicone Rubber

Nocking points and tube applied to piano strings

S ometimes ‘less’ is ‘more’. For ‘prepared piano’, you don't necessarily need to throw all sorts of heavy hardware, and car keys, bolts, screws, weatherstripping, and other violent junk into your piano and treat your piano like a percussionist’s rubbish bin.

F or one thing, the piano suffers. For another thing, the sonic consequences are just too extreme, and draw the audience’s attention to the performer and to the outrageous thing the performer has done to the piano, and detract from the audience’s actually listening to the music that the prepared instrument makes. Sometimes, instead of a visual ‘spectacle’ or sonically ‘provocative stunt’, the comparatively subtle acoustic effect you want can be gotten just by inserting some tiny objects that are gentle to the piano and that can be as easy to apply and remove as, say, a mute on a violin or other stringed instrument is easy to apply and remove.

T he do-it-yourself widgets below don’t ‘mute’ anything though. They dramatically change the pitch of each string they are applied to—from a few tens of ‘cents’, up to as much as a major sixth.

A nd you can’t create this sort of note-by-note harmonic effect with Pianoteq® or other synths; those establish harmonic attributes globally, applying them across the entire keyboard, not note-by-note.

F irst get yourself some Sugru®. It comes in a wide variety of colors, not just the orange that appears in the pictures here.

N ext, get yourself some 5 mm OD brass tubing and 5 mm OD brass archery nocking points (see links below). Also get yourself some 22 AWG copper wire, or whatever convenient gauge is slightly smaller than the diameters of the various piano wires where you intend to place the nocks.

T hen with your Dremel® handtool fitted with an abrasive saw (circle disc), cut your brass tubing to the lengths you want.

I have used tubing lengths from 30 mm to 70 mm to create weights ranging from 3 gm to 7 gm. For strings in the bass register, obviously you can use larger-diameter brass tubing.

E ach Allen Co (Broomfield CO) nocking point (Part No. 540) weighs about 400 mg when its lumen is filled with Sugru® silicone rubber.

N ext, cut one lengthwise slit in the side of each segment of brass tube with the Dremel® handtool.

C ut pieces of copper wire with a wire cutter or snips, about 2 cm longer than the length of each brass tube or nock. Use a needlenose pliers to put a crook or loop in one end of each wire, so you will be able to easily grasp the wire between your thumb and index finger, and so you will also have a loop by which to hang each piece up in a safe place while the Sugru® cures. Alternatively, you can get a piece of florists’ foam or styro at a hobby shop and stick the straight end of the copper wire into it after the nocks have been penetrated by the wire.

L ay all of the brass bits and archery nocking points and copper wires out on your worktable on a piece of plastic or a plastic kitchen cutting board. This will faciliate clean-up and prevent the Sugru® from smudging any surface you care about.

O pen a 5 gm sachet of Sugru®. Roll it around in your fingers for a few seconds. It has the consistency of soft modeling clay at this point.

Y ou can press the Sugru® into the lumen of a brass bit with your fingers and trowel it nice and even with an artists’ spatula.

T hen take a copper wire of the length appropriate to that brass bit and gently push the straight end of the wire lengthwise through the Sugru® in the center of the lumen. The copper wire adheres to the fresh Sugru® a little, but you can easily poke the wire through, so that a centimeter or so of bare wire sticks out beyond the end of the nock/tube. Hang the wire with the Sugru® nock/tube (or insert the straight into florists’ foam) in a safe place where it can remain undisturbed for at least 24 hours.

C ontinue, filling each of the brass bits and penetrating their centers with the copper wires. Set your collection of Sugru® piano nocks aside in a cupboard—someplace at about 20°C (68°F) and away from sunlight.

F or your convenience, make a 5 mm ball of Sugru® and set it aside in the same location with the rest. Wait at least 24 hours for the Sugru® to cure. Pick up the 5 mm Sugru® ball and squeeze it. If it is firm, then you know that the curing process is complete and it is okay to proceed with the next step.

T ake a razor blade or X-acto® knife and cut radially, directly down to the copper wire. Mount each in turn in a PanaVise® or other suitable holder and slice the silicone in the lumen lengthwise, to enable the nock/tube to slide onto a piano string. Then gently rotate the copper wire loop clockwise and anticlockwise 45 degrees or so, to release the wire’s surface from its attachment to the Sugru® silicone. Pull lengthwise to extract the copper wire out of the silicone rubber hole it’s been embedded in. Use your X-Acto® knife to trim any excess Sugru® from the slit or the ends of each nock/tube.

Slicing silicone in nock core with X-Acto knife

H ere is how the Sugru®-filled brass tubes and bow-hunting archery nocking points look:

Allen 540 nocking point filled with silicone

A nd the picture at the top of this post is how they look when you push the nocks and tubes on, their slits going over the piano wires so that each piano wire is seated in the center, in the cylindrical ‘cast’ made by the copper wire.

O n notes that have 2 or three strings, if you apply a tube or nock to one of the strings, you will create a sound where the weighted string is significantly lower in pitch than its companion string(s). In the upper register, my 3 gm to 7 gm tubes make the notes sound like Chinese bronze bells with the nipple-like bosses.

Y ou can slide the weight close to the middle of the string and it will mainly lower the fundamental and second harmonic of the string. If you move it nearer to the end of the string, it will lower the third and higher harmonics much more strongly.

I ’ve created a little Excel spreadsheet (link below), which helps you to calculate how much detuning you can expect as a function of changing the average mass of a string by adding weight to it. Obviously, this simple spreadsheet does not tell you anything about how the higher-order harmonics change, given that the weight is localized in a particular position on the string, not spread over its entire length.

P lease add comments below or email me to comment on your experiences with these Sugru® prepared-piano kluges.