{"id":35,"date":"2025-04-24T07:48:49","date_gmt":"2025-04-24T07:48:49","guid":{"rendered":"http:\/\/mrbenshoof.com\/JeffsPlayground\/?page_id=35"},"modified":"2025-04-25T20:58:08","modified_gmt":"2025-04-25T20:58:08","slug":"stepper-motor-music-mar-2025","status":"publish","type":"page","link":"https:\/\/mrbenshoof.com\/JeffsPlayground\/stepper-motor-music-mar-2025\/","title":{"rendered":"Stepper Motor Music – Mar 2025"},"content":{"rendered":"\n

I love to learn about new tools via hands on experience. I decided I wanted to learn how to control a stepper motor with an Arduino. I was pretty new to stepper motors but eventually I figured it out using the Arduino IDE built in “Stepper” library.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

I noticed that the sound the motor made was amplified by the wooden desk – and that it also made a distinct note! Using a piano I found that note to be G. Making the motor play a song was my next goal.<\/p>\n\n\n\n

Through trial and error I chose notes on the piano, and found what speed (rpm) it took to make the motor match that sound.<\/p>\n\n\n\n

I did find that as I went lower (slower) the note became quieter and less audible, and same with going too high (faster), so I only found speeds for notes D3 through F#4.<\/p>\n\n\n\n

Using these speeds I made a simple program to ‘play’ each note needed for “Happy Birthday” in order. <\/p>\n\n\n\n

Two issues arose from this method of playing the song:<\/p>\n\n\n\n

1) Each note was played by telling the motor to move to a fixed number of steps (200 per rotation), and when each note does this at different speeds, the notes are different lengths.<\/p>\n\n\n\n

2) The notes seemed to meld from one to the next, it was a little difficult hear distinct note changes.<\/p>\n\n\n\n

The first issue required setting the amount of steps the motor needed to move for a note, to be proportional to the speed for that note. For example G is played at 60 rpm, so moving the motor 60 steps has the same duration of playing A# – requiring 70 rpm – 70 steps.<\/p>\n\n\n\n

The second issue was much simpler, and was solved by just changing the direction the motor moved each note (moving negative steps).<\/p>\n\n\n\n

Program<\/h2>\n\n\n\n
#include <Stepper.h>\n\nconst int stepsPerRevolution = 200;\n\nint SongSpeed = 2;\n\n\/\/note speeds\n\/\/double letter = next octave\n\/\/note+S = sharp\nint D = 44;\nint E = 50;\nint F = 53;\nint FS = 55;\nint G = 60;\nint GS = 63;\nint A = 66;\nint AS = 70;\nint B = 74;\nint C = 79;\nint CS = 84;\nint DD = 89;\nint DS = 93;\nint EE = 99;\nint FF = 105;\nint FFS = 110;\n\nStepper myStepper(stepsPerRevolution, 10, 11, 8, 9);\n\nvoid setup() {\n  \/\/ initialize the serial port:\n  Serial.begin(9600);\n}\n\nvoid loop() {\n  \/\/HAP\n  myStepper.setSpeed(D);\n  myStepper.step(SongSpeed * (D \/ 2));\n  \/\/PY\n  myStepper.setSpeed(D);\n  myStepper.step(SongSpeed * (-(D \/ 2)));\n  \/\/BIRTH\n  myStepper.setSpeed(E);\n  myStepper.step(SongSpeed * (E));\n  \/\/DAY\n  myStepper.setSpeed(D);\n  myStepper.step(SongSpeed * (-D));\n  \/\/TO\n  myStepper.setSpeed(G);\n  myStepper.step(SongSpeed * (G));\n  \/\/YOU 1\n  myStepper.setSpeed(FS);\n  myStepper.step(SongSpeed * (-(FS * 2)));\n  \/\/HAP\n  myStepper.setSpeed(D);\n  myStepper.step(SongSpeed * (D \/ 2));\n  \/\/PY\n  myStepper.setSpeed(D);\n  myStepper.step(SongSpeed * (-(D \/ 2)));\n  \/\/BIRTH\n  myStepper.setSpeed(E);\n  myStepper.step(SongSpeed * (E));\n  \/\/DAY\n  myStepper.setSpeed(D);\n  myStepper.step(SongSpeed * (-D));\n  \/\/TO\n  myStepper.setSpeed(A);\n  myStepper.step(SongSpeed * (A));\n  \/\/YOU 2\n  myStepper.setSpeed(G);\n  myStepper.step(SongSpeed * (-(G * 2)));\n  \/\/HAP\n  myStepper.setSpeed(D);\n  myStepper.step(SongSpeed * (D \/ 2));\n  \/\/PY\n  myStepper.setSpeed(D);\n  myStepper.step(SongSpeed * (-(D \/ 2)));\n  \/\/BIRTH\n  myStepper.setSpeed(DD);\n  myStepper.step(SongSpeed * (DD));\n  \/\/DAY\n  myStepper.setSpeed(B);\n  myStepper.step(SongSpeed * (-B));\n  \/\/DEAR\n  myStepper.setSpeed(G);\n  myStepper.step(SongSpeed * (G));\n  \/\/[NAME]\n  myStepper.setSpeed(FS);\n  myStepper.step(SongSpeed * (-FS));\n  \/\/[NAME] 2\n  myStepper.setSpeed(E);\n  myStepper.step(SongSpeed * (E));\n  \/\/HAP\n  myStepper.setSpeed(C);\n  myStepper.step(SongSpeed * (-(C \/ 2)));\n  \/\/PY\n  myStepper.setSpeed(C);\n  myStepper.step(SongSpeed * (C \/ 2));\n  \/\/BIRTH\n  myStepper.setSpeed(B);\n  myStepper.step(SongSpeed * (-B));\n  \/\/DAY\n  myStepper.setSpeed(G);\n  myStepper.step(SongSpeed * (G));\n  \/\/TO\n  myStepper.setSpeed(A);\n  myStepper.step(SongSpeed * (-A));\n  \/\/YOU!\n  myStepper.setSpeed(G);\n  myStepper.step(SongSpeed * (G * 2));\n}<\/code><\/pre>\n\n\n\n
The SongSpeed variable, simply multiplies the duration of the notes to make the song faster or slower. Each note is a half note, and then multiplied or divided by 2 to make whole and half notes respectively.<\/p>\n\n\n\n
One quick cool thing to note, is that the ratios of the speeds from one note to the next sequentially, is pretty comparable to the ratios of those notes’ known frequencies. The ratio of a 440 Hz A to a B at 493.8 Hz is ~ 0.8910. My A at 66 rpm and B at 74 rpm is 0.8918!<\/p>\n\n\n\n
Results<\/h2>\n\n\n\n
In hindsight I should’ve also put in rest notes to give better cadence to the song, however here’s the final result. The Tupperware is an addition I found increased the volume of the sound.<\/p>\n\n\n\n