Bass Guitar

Play this model bass guitar by sliding the shuttle along the neck to select one of the 7 color-coded frets then pull the pluck trigger lever to sound the note. The guitar can use the internal hub speaker to produce simple "beep" notes, or you can connect the hub to a smart device (smartphone, tablet, or computer) with the LEGO MINDSTORMS software running to allow the hub to send realistic bass-sounding audio to it. If you hide your phone in the "amp" stand, the sound will come from the amp!

In "Free Play" mode, the 7 frets give you 7 notes in a blues scale that you can improvise with however you want.

For another kind of challenge, pull the hub out from the guitar and place it on the stand nearby like a music reading display, then you can use "Song/Game" mode to read simple music notation on the hub for pre-programmed songs, or try to play along and hit the right notes in a simple game inspired by Guitar Hero. Programs for the bass pattern for two simple songs are provided, and you can copy and edit these programs to make your own songs to play along with.

Building Instructions

Bass Guitar


Hub Stand


Using Game Mode

The Song/Game mode program "Bass Get Lucky" allows you to read music for a simple version of the bass line for the song "Get Lucky" by Daft Punk. Pull the hub out from the back of the bass and put it on the Hub Stand facing you.

Toggle between Internal and External Audio

Press the left arrow button on the hub to toggle between internal speaker output (beeps) and external audio. For external audio to work, a smart device (phone, tablet, or computer) with the LEGO MINDSTORMS app installed and running must be connected to the hub, as if ready to download a program to it. If the connection is successful, toggling into external audio mode should sound a sample bass note through the device (and back to hub speaker mode will sound a beep from the hub). You may need to try a few times at first to allow the software to connect the audio.

Toggle between Cheat Mode and Game Mode

Press the right arrow button on the hub to toggle between Song ("Cheat") mode (flashes green light on the hub), and Game mode (flashes yellow light). In "Cheat" mode, all you have to do is pull the pluck trigger once for each new note, and the program will automatically play the correct next note in the song. You can use this to help learn the song and the expected bass part. In Game mode, you also need to select the correct fret indicated or the game will sound a "wrong note" beep and flash the red light on the hub.

Playing the Game

Playing the game is much simpler than the real Guitar Hero game. Timing is not important (unless you want to play along with real music). Each time you pluck the lever, the next note plays. So you can play as slowly as you want as you are getting used to it. Only 5 frets are used in the game: white through yellow. The red and black frets will act the same as the yellow fret. The correct next note to play is indicated by the position of the pixel on the bottom horizontal row of the display. The next 4 notes in the song are shown on the rows above. Each time you trigger a note, the display shifts down for the next note.

The bass groove for Get Lucky is coded as having a very simple rhythm. It is 8 measures of 4 quarter notes each. Each note gets one beat in the song. After 8 measures (32 notes), the pattern will keep repeating over and over, which works fine for this song.

Playing along with the Real Song

After practicing a bit by yourself, you can try playing along with the real song "Get Lucky" playing on another device or on the same device mixed with the MINDSTORMS audio. One challenge is that the bass part of Get Lucky starts in right away, so you can't easily tell when to start. You can hit notes as necessary to catch up, or you could just wait out the first 32 notes of the song and come in at the start of the first repeat. Once playing, the main challenge is trying not to get off by a note or two. Unlike the real Guitar Hero, the program does not know where you are supposed to be in the music, so if you get off by a note, you will keep missing notes until you figure how to get caught up or re-synched with the music. Practice helps!

Making your own Song

If you know a little about music (piano especially), you can copy and modify the Bass Get Lucky program to try making your own songs. Start by loading the program into the MINDSTORMS software and using File -> Save As to make a copy of it with a new name. Then find "Part 2" of the program where the song notes and frets are defined (see program images above). This is the only part you will need to change.

The song is defined as a series of "Note (n) at fret (f) blocks". This specifies the next note in the song and which fret to assign it to. See the standard Play Beep block in the MINDSTORMS software and click on the note number to see the piano keyboard display to help you find note numbers. The fret number should be 1-5, corresponding to the fret position left to right (white to yellow). You can assign any note to any fret number, and what note that fret previously played doesn't matter. Like the real Guitar Hero, this allows you use any notes and design whatever required fret pattern you want.

When designing your own song, keep the rhythm simple and slow. External audio cannot react very quickly, and the quarter notes in "Get Lucky" are about as fast as it can go. You can try fast stuff with the internal hub speaker mode if you want though.

The program "Bass Smoke OTW" is an example of making a new song this way. It has a very simple bass groove from the song "Smoke on the Water" by Deep Purple.