Category Archives: Hardware Projects

The Pitar! #3: Hello Fretboard

Part of my daily routine after getting up is checking the postbox for anything (mostly china stuff). When I looked inside today, I found that my buttons had finally arrived!
Now I still need the resistors to actually start building the Pitar, but I couldn’t resist mounting the buttons on the nails that I had bought for that. It worked really well, but it turned out much smaller than I thought it would:


That are 24 frets (aka 6 buttons each)

Here’s my 15 fret ukulele for comparison:


Yes, I’ve picked up a uke! It’s so cool to play!

So the final Pitar isn’t gonna be much larger than an ukulele. I don’t really mind it that much because I’ve gotten pretty accustomed to the small size of the uke, but I don’t think a full-sized Gameboy will fit as a Head now. Maybe a Gameboy Pocket will be small enough… or one of those old McDonalds Gameboy Toys (I think I have one lying around somewhere). And if that doesn’t work out I can still do a custom Gameboy-shaped head or just go headless.

That’s all for this time folks! I’m gonna get back to this when the resistors arrive.

The Pitar! #2: Solo Mode and Button Mounting

I’ve been watching some electrical guitar solos and I noticed that players often just press down the strings to make tunes and don’t strum at all, much like playing a piano. I like that kind of playing, so I will mount a switch flip on the guitar for switching between solo mode and regular chords mode. I don’t know how it works on electrical guitars, but this should work well on my build.

Another thing I thought about is the mounting of the string buttons. Like I mentioned in my other post, most buttons including the strings will be mouse buttons. The ones I’m ordering have two holes of 2mm:

So what I will do is mounting them on 2mm nails which will be hammered through the side of the guitar neck.

It’ll be quite a while until the essential parts arrive, so further build updates won’t be very soon I’m afraid. But I’ll share any new idea or plan that come to my mind!

Feel free to tell me what you think đŸ™‚

Rocking out Digital Style: The Pitar! #1: Inital Idea and some Planning

Heyo folks!

I know it’s been forever since I last wrote anything on this blog, but I want to change that!
Recently I’ve been learning to play the guitar. I’m having a lot of fun doing that, and it reminded me of an idea I had floating around in my head for years: a digital guitar.
Before starting to play an actual guitar though I had no clue how to actually play one so the idea was always postponed. But NOW…

The concept is simple:
Instead of six strings with 24 frets (that are the nudges you press the string on so the note changes) each string will be a row of buttons and resistors wired in a way that each button changes the resistance, effectively making it a variable resistor. That value is then fed into an ADC which then feeds the signal into a Raspberry Pi Zero, which plays the corresponding sound sample.

For Controls I have this in mind so far:

  • a volume knob (obviously for volume control)
  • a rotary sensor to switch between different instruments/sample libraries
  • the “strings” with 24 buttons/”frets” each, resulting in 144 buttons (thats gonna be a lot of wiring)
  • two buttons for switching the octave up and down, because why not make it virtually 24*x frets (x being the number of octaves)
  • 6 buttons for strumming or playing the strings individually
  • 6 metal contacts for better strumming. The same contacts as the strumming buttons, but activated by touching them with a metal pick which will be connected to the guitar via cable
  • on/off switch and power button, because I heard the Pi doesn’t like suddenly being cut off the power

My current plan for the string setup is this:


In theory, pressing one of the switches (which will be mouse buttons since they are nice and easy to press) should change the resistance individually. pressing an additional button above the first one shouldn’t change the value, just like you can touch the string of a guitar before the point where you press it down without changing the tune.
I’m not very knowledgeable in electronics though. According to Crocodile Clips (which is the program I used to set the above thing up) it works, but the amperage value only very slighty changes when pressing the first few buttons while the last few buttons cause very big amperage jumps. I’m not sure how that will work out in practice.

As for design, I decided to make it in the style of 80’s e-guitars because I love their funky look. Since I don’t need a guitar head (all “strings” are always calibrated) I could leave it out, but for stylistic reasons I decided to make it a Gameboy. The Display will glow while playing the Strings and maybe some more graphical effects. I could even use some of the buttons for controls, although I’ll be limited to things like on/off and the like since pretty much all other controls should be accessible on the fly, so it makes sense to put them near the strumming section.


This is roughly how it should look in the end. I might go for a different body form, depending what is the most comfortable while playing.

The parts that I already have are:

  • a Raspberry Pi Zero as the brains ($5)
  • an old Gameboy (although I might get transparent china-made parts instead) ($5-15)
  • some old speakers of which one should suffice (basically free)
  • power switch, button for powering off, potentiometer knobs and probably also a charging and earphone jack (about $6 altogether I guess)

What I still need:

  • the mouse buttons (I’ll get a 200-pack for $13.20)
  • the resistors (200 for $1.20)
  • a display for showing the current instrument (and development info) ($1.90)
  • a metal pick ($1.20)
  • some shielded cable (about $5 at most I guess)
  • Amp with Volume knob ($1.56)
  • an ADC (I’ll use the MCP3008T-I/SL, $2.60 for two)
  • a rotary sensor ($0.47)
  • batteries, charging board and some voltage regulators maybe (I may actually have some of that lying around, about $10+ depending on the battery capactiy)
  • the guitar casing. I’ll probably get laser-cut wooden pieces, at least for the first version. (about $10-20)

So all in all the Pitar will cost me about $63-83 or more. Still cheaper than the cheapest e-guitar I could find, and definitely more stylish and cool!

Any thoughts, tips or other comments are welcome!

Pi Handheld Mini (1)

The Raspberry Pi Zero is a nifty little device and many people use the small form factor of it to make a handheld gaming system. That is what I plan on doing as well. I actually want to make two handhelds: One that focuses on a small form factor while still being comfortable to play with and one that focuses on a big screen and battery life.

Since I only have one Pi Zero so far (because usually ordering is limited to one per order) and the bigger screen and battery are more expensive I will start with the small one.

I already made a simple 3d model (more of a sketch) and a parts list:


This is the (very generic) model for the Mini handheld: You have your regular dpad and face-buttons, along with volume and menu keys. The overall layout is similar to that of the Letcool N350JP:



click to get to aliexpress

The actual functions of the buttons are not set in stone. Also notice that my handheld will feature two shoulder buttons. Probably less interesting for most emulation, but useful for functions like quicksave and load.


On the bottom we have dual speakers, audio jack and (full-sized) usb port. The usb port may stick out a little in the final design, but I hope it won’t be a bother since you don’t usually have your hands on the bottom of the handheld.


The interior shows that a lot of space is used for the battery. However, the handheld will only be about 11*4*1 cm, so the battery power will be fairly small (more details on that later). Next to the battery we have the Pi Zero. There is no micro sd slot on the outer side of the handheld because I do not plan to make it removable without opening up the handheld. Copying files will be done via usb. I do want to make the back plate removable though, because it also helps with possibly needed repairs.


If we take off the Pi Zero and the Battery we can see the circuit boards of the display, front and shoulder buttons.

Things that I did not include in the model are the battery charging circuit and port, battery indicator, audio circuit board, controller board and 5v boost module. I plan to cut up and minimize those boards and cram them below the Pi Zero. That should be enough space, if not I may have to make the handheld slightly bigger.

I did not really decide on a controller to use yet. A china N64 controller would be good since it features enough gaming buttons (no counting menu and volume, although maybe i can use the analog inputs for that) and uses very few GPIO, which leaves the USB port free. I do not know though if i can cut the board enough to fit it in the handheld.


  • 11x4x1cm
  • 2.2 inch LCD, 320×240 resolution
  • about 800mah battery (a nokia BL-5B)
  • Dpad and 10 function buttons
  • power and menu button
  • volume buttons
  • stereo sound

Let me know what you think and if you have any questions!

NES Bluetooth Controllers 1: The Plan

Lately I’ve been showing a friend of mine great retro games which he never played or even heard of (he started gaming at a later point in time).

Currently we are playing the Gameboy Colour Zelda games, which are some of my most beloved games of all time!

Now here’s the thing: My friend has a very cool gaming setup: His Huge Flat TV is in his living room, with his computer hooked up to it via HDMI in the other room (the cable is VERY long and even goes through the wall). Also he’s got himself 4 ps3 controllers and a nice sofa. perfect setup, right? Well not for 8 bit games. What I’m still missing is better fitting controllers. Don’t get me wrong, the PS3 controllers are great, but for retro games they aren’t perfect. Playing with the analog stick feels weird to me, and playing with the Dpad hurts my thumb after a while. So what do we do?

Let’s get some good old NES controllers!

Originally I wanted to get cheap NES USB controllers from aliexpress, like these:

nes usb controller
click the picture to get to a shop on aliexpress

But then I thought… Look at those buttons. This is never going to be as good as an original controller, so what’s the point in getting them? Could as well use the PS3 controllers then.

So what I’ll do is get two original NES controllers, gut them and put inside bluetooth controllers.

So which bluetooth controllers will I use? Original PS3 controllers are too expensive to be gutted (I’m too cheap to do that) and also they have way more buttons than necessary.
Since a while those small keychain bluetooth controllers are being sold everywhere (online at least, do I look like I go outside?):

They are sold in china and in german online stores for under $5 and have enough buttons for old games. NICE!

So what I’ll do is order two of these, get two used NES controllers and fuse them together. Maybe I will add shoulder buttons for GBA games (the bluetooth gamepad should have enough buttons for that).