At last! A MIDI ukulele

There are a number of MIDI-enabled guitars out there, but did you know now there is also a MIDI ukulele? Kudos to Maker Hart for their courage in developing the DU-one and EU-one instruments. They were kind enough to send me a free DU-one so I could write this review. Short version of this rather long article: it takes a lot of effort and frustration to get it to work, but in the end it is all worth it.

If you have read more of this blog before, you will know that, in addition to technology and writing, I’ve been quite taken with ukuleles lately. Their 4-string simplicity makes them supremely easy to learn, especially at a not-so-young age, and they sound happy and generally terrific. But I love technology as well, and those acoustic ukuleles, even though they sound great, don’t quite cut it for me. I want to be able to make the instrument sound like anything. I have a fairly large collection of synthesizers (mostly software) which I could play with the same simple technique if only I could get a MIDI signal out of the instrument.

Now, 6-string guitars featuring MIDI output have existed for a while, with mixed results. You can get a fairly comprehensive history, along with some benchmarks, in this article, and also on my very late review of the Rock Band 3 Mustang pro controller here. Since 6-string guitars have a much larger market than ukuleles and their MIDI types have never sold well enough to stay in production, you can see how courageous it is for Maker Hart to be releasing a MIDI ukulele these days.

Before I give you my impressions of the instrument, let me first tell you what my expectations were. The essence is being able to play with a small a delay as possible. Then, I also expected some decent sounds, ability to alter the tuning, transpose, and so forth. Ergonomics is also important for something you’re going to be holding close to your chest. Another consideration is how easy it is to tweak the instrument, in case the built-in software is no good.

The DU-one unit for my review arrived in a quite heavy but neat box, shipped directly from Taiwan. I must add that the instrument is marketed as a DIY project, so it comes disassembled so you can enjoy putting it together. Mercifully, this involves no soldering, but rather fitting of components and some tightening of screws here and there. Most of the assembly has to do with the concert-size neck (7.5 inches from nut to 12th fret), which is composed of several layers of plastic and electronics that must be placed in the correct order, and its hinged attachment to the body. All small parts come in a plastic box, containing some spares of most screws and other parts, which is a nice touch since those parts get lost so easily. The body is clear plastic on the top and heavy steel on the bottom.Possibly too sturdy for a ukulele, but it has buttons to add a strap (not included), which is a definite must. The EU-one model, which apparently is identical to the DU-one except for the addition of a piezo sensor on the upper surface to be used as a drum pad, comes with a wooden upper body rather than plastic.

Maker Hart states that assembly should take 2 to 3 hours and require only the two screwdrivers and multi-wrench included in the kit, plus maybe a larger screwdriver. There is an assembly manual containing color photographs at 126 points in the process, but which unfortunately ends before the whole process is complete (more on this later). Concerning the tools, I found I also needed other stuff in order to get done: some lubricant (the shafts in the kit have a hard time getting into their bushings, and a lot of friction once in), some strong glue (one of the parts came broken and I had to fix it), tweezers (some steps require impossibly thin fingers), and rubber cement (which I used for the last few steps not included in the assembly manual). I grew up with Erector sets and so I think I’m fairly dexterous pushing shafts into real tight bushings and maneuvering ribbon cables around tight spots, but I still had to sweat it out more than twice at some points in the process, which were physically difficult to carry out although the pictures were quite clear about what was supposed to happen. I suspect many users will give up in the middle of the assembly process. The fact that many pictures are labeled in Chinese or incorrect English (“tap” instead of “tape” comes to mind) doesn’t help much.

And then, the assembly manual stops before you are actually done. Left out was the installation of the “strum pad” (my name), which essentially involves removing a piece of waxed paper and letting the adhesive backing attach the part to the strum sensor area (easy, but people might turn it 90 degrees inadvertently, thus ruining the product), and then there is the neck playing surface, which I will call “the fretboard.” The instructions take you as far as laying a sensitive layer on a metal plate, which is then connected to the electronics, but stop before you can add a rubber pad with raised “strings” and “frets” and a printed decal with the same. I spent quite a while trying to detach the decal from its white paper base, and in the end I concluded that they were one piece. So I glued the whole thing onto the fretboard with rubber cement and kept it this way for several days, thinking that I was done. Only when I found the fretboard to be rather unresponsive did I try again, and this time the decal detached from the backing paper and I was finally able to place it correctly on the fretboard.

But still I wasn’t done. The factory program assumes that the “frets” are located at certain positions on top of sensing strips that are first glued to the neck. It seems the finger position information gathered by the strips is analog, and requires calibration since the location of the “frets” relative to the sensing strips depends on how you glued the decal to the neck. The calibration procedure explained in this video (mislabeled “Chord Setting” but never mind) requires the installation of Arduino software on your computer, then uncomment a part of the program, write down what it gives you when you run the procedure, and then put those numbers back into the program and upload it to the instrument. Make sure you are pressing the fretboard right at each rubber fret. If you don’t do it your fretting won’t be picked up correctly and your playing will sound awful. Again, neither the assembly nor the user manual say anything about this.

Once everything was assembled, I just added a 9 volt battery, plugged the DU-one into an amplifier, turned it on, and began strumming. It can also work out of 5 volts from the USB cable, which makes me wonder whether it wouldn’t have been better to use 4 AA batteries and waste less energy; indeed, it drained a new 9 volt battery in just three days of testing on and off. There’s also a 3.5mm jack to plug in headphones but I got sound only in one ear, not stereo as the picture says. Likely a defect. The “tones” were not bad, though, with the possible exception of the “electric guitar” which, inexplicably, is set to zero sustain and sounds rather weird as a consequence. This is because the DU-one hardware has a sound chip containing a full General MIDI set of instruments, ten of which can be selected from the middle knob. Speaking of the knobs, there are three of them. The one on the left is an on/off switch and volume control. The middle one selects the instrument patch being played, out of a list of ten. The rightmost one selects the “mode” of the instrument, out of five choices. With the factory software, these are: 1, normal playing mode, using single notes for single “string” strumming; 2, a sort of trilled strumming of each string; 3, arpeggiated sequence for each string; 4, drums mode, where each “string” is a different cymbal or drum; 5, chord mode, where you fret only the fourth string to play whole chords as you strum all the strings. I didn’t care much for mode 3 so I ended up re-programming it into something else.

And speaking of software, there are two ways to control the DU-one other than with the physical knobs. The first is with an iOS app (there is an Android version as well), that lets you pair the instrument via Bluetooth, and then change settings not available from the hardware knobs. Think of it as an extension to those buttons. The second is by connecting the instrument to a computer via USB, and then running Arduino control software on the computer. Yes folks, the DU-one has an Arduino-compatible board inside, which makes it eminently tweakable. Maker Hart includes the default settings in an Arduino program that comes with the instrument and is available for download here, but then you can change it to your heart’s content. You can make any string and any fret sound like anything you like.

You have to download the mobile app from the appropriate app store, which takes some faith because the description is in Chinese. Once installed, though, it is quite easy to use. It is organized as a panel divided into quadrants, which do the following, moving clockwise from the upper left quadrant:

  1. Pair the device to your phone or tablet. Foolproof and successful every time. No complaints here. This is the only way to pair the DU-one with a tablet, though, as pairing without the app never works. Once the device is paired, it remains connected until its power is turned off, even if the app is removed from memory.
  2. Change the tuning. You have three choices: ukulele (high G), guitar (actually, baritone ukulele since it is only four strings), bass. Easy, but it left me wondering why I had to go to an app in order to do something that should be on the hardware itself. I also was left wanting for a sort of software capo, which the Jamstik and other similar devices have.
  3. Rhythm select. This is for the four accompaniment buttons at the root of the neck. You can select the tempo and the pattern played by any of the four buttons.
  4. Chord select. This one assigns a chord, out of a list, to any fret for use in mode 5. Pretty handy, but the list of chords available was quite incomplete, missing things like F7 and all diminished chords, which do get a lot of use in a ukulele.

Once the device is paired with an iOS device, then you can use it as a Bluetooth MIDI controller in apps such as GarageBand. You can also pair it directly through GarageBand and similar apps that have the ability to connect to a Bluetooth controller. This is one of the most interesting things about devices like the DU-one, since the sounds generated by a computer or even a mobile device are an order of magnitude better than what the onboard controller can produce, and so it is a shame that this does not work on Android, possibly because Android does not have an equivalent of the excellent CoreMIDI capability of iOS. The DU-one appears on iOS as “Bluetooth MIDI controller,” which is not what Maker Hart says, but does the trick all the same. All MIDi information is sent through channel 1 (channel 10 for drums), The strings are velocity-sensitive, rather than trilled, when the instrument is set in mode 2. What’s even better, I could not sense any latency between the time a “string” was touched and the time it sounded, even when strumming all strings quickly. This is very important and makes the DU-one a champ where it matters. I was totally sold at that point, and I forgot all the pain involved in the assembly and calibration. I played all sorts of Tin Pan Alley favorites with the sounds of banjos, electric pianos, and even steel drums, to say nothing of all the soft synths I have installed in my iPad.

This is a good spot to talk about the playing experience. As I said earlier, you have to get a strap (none is included, but it should be) because the instrument is very heavy. Then, the “strings” you strum are actually stiff little ridges that stick a couple millimeters from the body of the instrument. Fortunately, they are located fairly close to the neck, as it should be for a ukulele. I normally use a soft pick (Mick’s Uke-1, in case you were wondering), which worked fine on this weird sort of “strings.” I suspect strumming with your fingers will leave much to be desired because of the location and the stiffness of said “strings.” Then, the “frets” are made of soft rubber, as are the simulated strings on top of them. The rubber is clear, which makes the “strings” nearly impossible to see at an angle; you actually have to feel them, which is not easy because they are so soft. If you have calibrated the fretboard, as describer earlier, you can put your fingers anywhere between two frets in order to produce a given note. There’s no such thing as string buzzing or dead strings, but the original software will mute the sound if the pressure on any string weakens, which is rather non-musical and happens more often than you’d like; fortunately this behavior can be improved by tweaking the software, although it doesn’t go away completely. Needless to say, there’s no way to bend strings or perform hammer-ons and pull-ups, which only the most expensive MIDI guitars achieve, and often not so well.

I takes some effort to adapt to the soft strings on your left hand and the hard strings on your right, but if you are not a complete novice this can be done in a few minutes, after which you’ll find yourself strumming happily in a variety of instruments. That is, if you use a pick. I’m not so sure about hand-strumming. One curious fact: notes are registered as soon as you touch a string, not when you release it. This is opposite the way things work in reality, but I hardly could tell the difference since so little time elapses from the moment the pick touches a string until it is past it. Note on touching allows the trilled Mode 2 to exist (handy for shamisen and mandolin), as well as playing full sustain instruments such as winds or organs. But again, you’d likely be using a keyboard to play those.

And then, there is the Arduino aspect. Yes, folks, this thing is Arduino-compatible and therefore fully reprogrammable. You don’t have to be stuck with the way any of the functions were set up from the factory. To use this feature, you need to get a miniUSB cable, which plugs in at the bottom of the device, and the other end plugged to a computer running the Arduino software. Select “Arduino/Genuino micro” as the type of device, then the port (should be anything except Bluetooth, since the connection is wired), and you’re set. You can see the program, test it, and change it. The first thing you’ll want to do is calibrate the fretboard, as I mentioned earlier.

I spent some time changing the function of the buttons at the root of each string, on the neck. The default function was to turn on and off each of the built-in rhythms. I reprogrammed the one at the root of the 3rd string so it would activate each of the rhythms in sequence, with a fifth position to turn them off. Then I added code to use the other three buttons this way: the one at the root of the 1st string raises the pitch of all frets 1 semitone; the one at the 2nd string cyclically selects one out of five different tunings (ukulele, guitar, and bass as in the table software, plus mandolin and C6-tuned cuatro, as in this other article); the one at the root of the 4th lowers it by the same amount, thus making a convenient capo. Then I decided to use the 16th fret positions, which aren’t going to get much use in real playing anyway, to select the instrument being played out of the full list of 128 instruments that are actually built in, not just the 10 on the middle knob. The strings on the ends moves the selection by one place up or down on the list, those in the middle by ten places.

Not content with these tweaks, I decided to replace the original Mode 3, which to me sounds rather silly, with a “tap” mode where notes sound as soon as you touch them on the fretboard, without using the strum pad. You can play with the neck folded, making a sort of mini-keyboard. I took most of the relevant code from Mode 1, a little earlier in the program. I also replaced the useless Bm chord selection with Bb, which does get a lot of use in ukuleles, and removed some triggers that were muting sounds too much, as well as the blacklist that some default patches have (an electric guitar without sustain, really?) in the Sustain function. The result is a tweaked control program, which I am including for your enjoyment in this link. I hope you enjoy it. At the very least, it can inspire you to come up with your own tweaks.

This is it folks. To summarize, I had a rough start with the harder than expected assembly, the incomplete manual, and the frets that had to be calibrated using missing software and taking cues from a mislabeled video, but in the end the DU-one was sounding sweet and delivering on its promise to put a full orchestra in a ukulele body. I altered its software to customize it more to my liking. I got my DU-one for free, but the average customer is being asked to part with $170 for the plastic DU-one, $229 for the wooden EU-one. This has to be set in contrast with the roughly $60 street price for a Rock Band 3 Mustang Pro controller, expounded in this article of mine, which does outside MIDI control almost as well (wired rather than wireless), and more expensive instruments. The similar You Rock Guitar, which also has a membrane fretboard but better “real string” strum section can be had for around $200 (used, since it’s not being made anymore). On the other hand, the very similar Jamstik+ (6 strings but no on-board sound production; everything is done on a connected iPad, and it has only 5 frets) is selling for nearly $300. The Artiphon instrument 1 (also 6-string and app-centric, and you strum on a narrow set of buttons, though you need to connect by cable) will set you back $400. All the competitors look quite cool when compared to the DU-one’s over-the-top geekiness. To make things easier, I am comparing the DU-one with the Jamstik+ and the Artiphon, as a table. I did ask the companies putting out the Jamstik+ and the Artiphon for hardware I could review, but they either declined (Jamstik) or did not reply (Artiphon), so the table is based on their published specs plus some videos I’ve found, rather than actual experience of the instruments.

DU-oneJamstik+Artiphon 1
strings 4 6 6
fret sensor location membrane infrared pressure membrane
strum sensor pressure membrane magnetic on strings pressure membrane
frets 16 5 12
bend, hammer-on No Yes Yes
wireless Yes Yes No
iOS app Yes Yes Yes
Android app Yes (no MIDI) No No
on-board synth Yes No No
speakers No No Yes
re-programmable Yes No No
price $170 $299 $399

I may add that, although the Jamstik and Artiphon videos are much slicker than those made for the DU-one, you can glean from them some unpleasant facts. For instance, the Artiphon’s membrane fretboard, although pressure-sensitive (the one on the DU-one is not) is divided into equal-sized “frets,” which basically throws overboard any pretensions of learning to play a real guitar with it. The Artiphon has no wireless connection, either, and must be tethered to an iPad at all times.

Is the DU-one worth for you? You decide. As for me, I really like the DU-one, warts and all.


  • Only MIDI ukulele in the market; this makes it much easier to play than a MIDI guitar
  • Built-in sounds are generally good, and can be made awesome (128 of them!) if you are willing to tweak the software as I did
  • It controls mobile sound apps and soft synths via Bluetooth (no wires!): both iOS and Android are supported
  • Assembly can be fun for a couple hours
  • The neck folds into the body, which makes it very portable
  • Tweakable via Arduino software
  • Support is only one email away and relatively fast; nice people too, though their English isn’t Shakespeare’s


  • Assembly requires a high level of manual dexterity
  • Incomplete assembly instructions
  • You need to run the Arduino software to fully set up the instrument, which is not explained in the manual
  • No software capo, though this can be fixed by programming
  • At least one useless mode; also fixable via programming
  • Heavy, and not precisely cool looking
  • Fast battery drain
  • Quality issues (on my sample, headphone output came through one ear only)

Final thoughts: Maker Hart has a winner here, especially if customers can purchase the instrument fully assembled and set up. If you like programming, or at least like my program here, you can have a lot more than what seems to come in the box.

5 thoughts to “At last! A MIDI ukulele”

  1. This is so much interesting thank you so much!
    I still have one really important question before considering buying one right now though:
    Can you MIDI record the EU-one or the DU-one in any DAW (like Garage Band, Pro Tools, Audacity, Pyramix, etc.), in such a way that you simultaneously and independently record each one of the four strings in 4 independant MIDI tracks?
    I mean for example if your four strings are set as G C E A and you hit them all at the same time, can you record this in 4 independant MIDi tracks, of which the first one contains ONLY G, the second MIDI track contains ONLY C, the third track contains only E, and the last MIDi track contains only A?
    That would be really, really, really, I mean really terrific!

    Thank you again!

    Lucas Remond

    1. The DU-one comes programmed so all MIDI information is sent through channel 1, so it would be quite difficult for the receiving program to tell which string each note was played on. But it is quite possible that you can change this by reprogramming the device.

  2. Thanks for your efforts .. I have ordered an EU-1 .. one thing that I’m not quite sure of is: can each string be tuned independently such as in all thirds, all fourths or all fifths?

    1. Yes it can, but you have to delve into the Arduino code to do this. The post contains a link to a modified code I made as I wrote the article, including some extra tunings, such as mandolin (all fifths) and cuatro (lower 1st rather than higher 4th).

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