Research->Media Art->Musical Robot->Music Derby

Provides information about media arts.  


Overview and rules
Music Derby is a game in which sound of music runs seven robots.
The player predicts which robot will go the farthest when a tune is over.
A single pitch is assigned to each of the four-legged walking robots that imitate animals such as deer, rabbits, and mice.
For example, the note C is assigned to deer, the note D is assigned to rabbits, and note E is assigned to mice.
When the note G is played, the pig moves forward.
When the note F is played, the giraffe moves forward,
and when the note E is played, the mouse moves forward.
If twinkle twinkle little star is played in C major key, which animal will go the farthest at the end of the song?
In C major, C is the tonic note, so you might expect that the deer assigned to C goes the farthest.
But in reality, the pig assigned to G wins.
This is because G appears most frequently on twinkle twinkle little star.
On the contrary, the cat never moves because B never appears.
In this way, Music Derby can visualize the frequency of occurrence of notes on the scale in a song.

The microphone picks up the sound played by the instrument.
Analyze the pitch with Arduino.
Rotate the motor to move the animal forward.

I tested pitch detection system with various musical instruments.
Keyboard type harmonica is not bad but missed some notes such as F.
Metallophone and toy piano have good reaction.
12 string guitar is not good, contrary to expectations.
Voice is not good, but it might be used with some tuning, I guess.
Maybe I need voice training also.
Recorder is the best instrument for pitch detection.
I think it's because it doesn't contain much harmonics.

(1) Play a sound from a musical instrument such as a keyboard. (Single note is desirable)
(2) Analyze the pitch of the sound with Arduino.
(3) Each animal corresponding to the note of C, D, E (Do, Re, Mi) advances.
For example, when the sound of E(Mi) is played, the third animal (because E(Mi) is the third note of C,D,E...) moves forward.
If the note F is played, the fourth animal moves forward.
(4) The animal in the foreground wins when one song has finished playing.

Older versions used fans to advance balloon animals.
Production process
These are Components.

Product Spec. Amount Price
Relay OMRON G5V-1 (DC3V) 1 \275
Gearbox TAMIYA 1 670
Arduino Pro Mini KeeYees (ATMEGA328P 3.3V 8MHz) 1 \360
Microphone HiLetgo (MAX4466) 1 \313
Battery box (AAA x 2) 2 \158
LED 2.3V to 3.3V 2 \100
Switch   1 \100
Connector & Cable   22 \60
Acrylic frame     \1000 to \2000
Screws M2.6 X 10mm    
Nuts M2.6 6 \50
Split pin M2 X 20mm 2  
Race course field
There are 7 courses from note c(Do) to note B(Si).
There is a step between each course so that the animals can go straight.
The name of the note is engraved on the course so that you can see which sound it is.

Animal and sound assignment

C Deer
D Rabbit
E mouse
F Giraffe
G pig
A Rabbit
B cat
Instrument used


Maker Music Festival 2022 "Awards of Merit" 3 stars
Original Mind 11th(2022) Making Culture Exhibition Awarded
Amazing Maker Awards 2022 3rd Prize in Artistic Category