Building an Electric Ukulele
Full Size Soprano Ukulele with Built-in Amplifier for under $60
The idea of one can make a real musical instrument out of 3D printer is always tempting. After played with Gakken’s awesome Mini Electric Guitar Kit, I couldn’t help but thinking: “Maybe I can start a 3D printed electric ukulele project, and I’m gonna make it open-source.”
The Design Concept
Earlier this year, after a few rounds of drinks with my friends in Beijing, I brought up this idea and immediately we decided to make a lightning shaped ukulele, as our tribute to David Bowie. Today, we’re glad to present you, the Ukulele.Design project, and its first product, Lightning Uke.
We started with sketches on notebooks, then Paper by FiftyThree app. After we’re on to something we exported it to SVG file, and make rapid prototyping in 123D Design. We tested those early stage STLs with Prusa i3 and Replicator 2.
Since our goal is to let people making it at home, size of printed parts are limited by printing area of mass-market printers; we constructed a soprano size ukulele with two parts, then added joints and a handle to hold it up. After we figured out the scale length, fretboard was designed by Fret position calculator as part of the neck.
Bill of Materials
- pegboard x 1
- LM386 x 1
- 10Ω resistor x 1
- 0.1μF (104) capacitor x 1
- 220μF capacitor x 1
- 10KΩ potentiometer x 1
- knob x 1
- 1W 8Ω 40mm speaker x 1
- switch x 1
- 9V battery snap x 1
- 27mm piezo x 1
(If you want to make an “acoustic” ukulele, replaced the body part with body-solid.stl)
- geared tuners x4
- 21 inch ukulele nylon strings x4
- 6.3mm jack x1
Purchase a DIY Kit?
If buying parts isn’t in your favor, or you don’t have access to a 3D printer, you could purchase a DIY Kit from the project website. We will donate part of the revenue to selected foundations that’s addressing digital divide.
1. Prepare printed parts
Print all 3 files in PLA, with following configuration:
- Infill: 20%
- Layer height: 0.20 mm
- Shells: 2
- Support material and raft: No
It takes a total of around 15.5 hours to print on Replicator 2.
2. Assemble the body
Slide the handle into neck, and insert joints into body. Snap it together to finish it.
3. Install the tuners
Get 4 sealed geared tuners (note there are left and right orientations). Slide tuners into body, tighten screws with washers.
4. String It Up
Get a set of 21 inch (soprano) ukulele strings.
Start with the 4th string, insert it into the top-most hole of headstock. Go around itself for a loop, then make two more loops in the same direction. Pull on the long end of string to tighten the knot.
Wrap the string over the bridge and around the body, insert into the tuner peg hole, tighten and tune.
Finish the rest of 3 strings, make sure strings sit in their corresponding bridge slots and nut slots, trim the strings as needed. Now you have an acoustic ukulele!
5. Solder the Circuit
Your ukulele is now playable, but what makes Lightning Uke stand out from the other ukulele is its built-in speaker and amplifier, so you can rock without a sound box.
We use piezo for pickup to receive vibration from the body, and to turn it into electrical signals; the amplifier is based on LM386 IC.
Get your tools and electronic parts, and solder the circuit with the following layout. There are many examples of LM386 based amplifier circuit can be found online, so adjust as you need. Solder the speaker, piezo and 6.3mm jack with wires, too.
6. Connect the electronic parts
Slide the speaker underneath the strings, glue it in the cavity, and glue the piezo at the bottom of body. Install the switch, the potentiometer with knob (as the volume control), the jack and the circuit board, save some space for the 9V battery, too.
Snap the battery in and slide the cover, your Lightning Uke is now ready to rock!
Remember I mentioned that Ukulele.Design is an open source project? All of its design, model and circuit layout can be found on the GitHub project page, and you’re free and welcome to make, modify and distribute it.
While making the Lightning Uke, if you encounter any problem, welcome to post questions on our Facebook page, we’ll be more than happy to help:
So here’s to the makers. Happy hacking!