⚠️ WARNING: This article is obsolete
Geek Spin - ATTiny44 Project Prototype
Some days you feel like working on projects to benefit humanity. The day I made this clearly wasn't one of those days. A little over a year ago, I got into a troll war with my friend Mike Seese. The joke, similar to that of rick rolling, was to get each other to unexpectedly click a link to the Hatsune Miku version of the leekspin song. After several weeks of becoming beyond annoying, I decided to make an actual Hatsune Miku which would spin her leek and bobble her head to the techno version of the Levan Polka for his birthday.
The goal was to create a minature Miku which would perform perfectly in sync with audio coming from a portable music player (iPod or something) and NOT require a computer connection. I accomplished it by sending some creative control beeps out of the left channel of the stereo signal. Although I didn't finish the project, I got pretty far with the prototype, so I decided to dig it out of the archives and share it with the world because it's pretty entertaining!
(look how close I came to replicating the original:
How did I do it? First off, I used servos. If you're not familiar with them, I suggest you look up how servos work. Perhaps check out how to control servos with AVR microcontrollers. Basically, their position along a rotational axis is determined by the width of a pulse on a 20ms time window. Anyhow, if I only had 1 servo to control (i.e., leek only), I'd have controlled the servo directly with PWM signals in the left channel - no microcontroller needed, easy as pie, problem solved. However, since I needed to control two servos, I had to come up with something a bit more creative. Although I could have probably done this ten different ways, the way I chose to do it was using a series of pre-encoded leek spin and head bobble motions, triggered by control beeps in the left channel of the audio cable. (The right channel was patched through to the speakers.) Below is a diagram of what I believe I did, although I didn't thoroughly document it at the time, so you might have to use your imagination if you decide to re-create this project.
The idea is that by sending bursts of sine waves, the circuit can rectify them and smooth them out to have them look to a microcontroller like a brief "high" signal. Each signal would tell the microcontroller to proceed to the next pre-programmed (and carefully timed) routine. With enough practice listening, watching, and tweaking the code, I was able to make a final version which worked pretty darn well!
LISTEN to the music with control beeps (it's a surprisingly fun listen)
A few technical details are that I used an ATTiny44a microcontroller (it may have been an ATTiny2313, I can't remember for sure, but they're so similar it's virtually negligable). The servos I used were cheap (maybe $4?) from eBay. They looked like the one pictured below. The servo position was controlled by PWM, but I manually sent the pulses and didn't actually use the integrated PWM in the microcontroller. I can't remember why I did it this way - perhaps because it was so simple to use the _delay_us() and _delay_ms() functions? I also used an operational amplifier (if I remember, it was a LM741) to boost the left channel control signals rather than rectifying/assessing the left channel directly.
This is the video which I mimiced to create my prototype (note how the leek in her arm and her head move exactly the same as the prototype I made - score!)
And how did I find out about this song? I actually saw it on the video below which was hosted on wimp.com. I thought the song was catchy, looked it up, and the rest was history. It's worth noting that (perhaps to avoid copyright issues?) the key was shifted two half-steps up. I get a kick out of the way the girl waves her arm in the beginning, mimicking the leek :)
Here are some of the images I made which I printed, glued to foam board, and cut out with a razor blade. I'm not sure how useful they are, but they're provided just in case.
... but sometimes Japan takes it a bit too far and things get awkward ...
Below is the code I used. Note that PWM that controls the servos isn't the integrated PWM, but rather a couple pins I manually pulse on and off to control the arm and head positions. Also notice how, in the main routine, I wait for the control beeps before continuing the next sequences.
// leek spin code - designed for ATTiny
// by Scott Harden, www.SWHarden.com
#include <avr/io.h>
#include <avr/delay.h>
void go_high(){
// sets the arm to the highest position
for (char i=0;i<5;i++){
PORTA|=(1<<PA0);
_delay_us(1400);
PORTA&=~(1<<PA0);
_delay_us(20000-1200);
}
}
void go_low(){
// sets the leek to the middle position
for (char i=0;i<5;i++){
PORTA|=(1<<PA0);
_delay_us(1900);
PORTA&=~(1<<PA0);
_delay_us(20000-1900);
}
}
void go_lowest(){
// sets the leek to the lowest position
for (char i=0;i<5;i++){ // takes 100ms total
PORTA|=(1<<PA0);
_delay_us(2300);
PORTA&=~(1<<PA0);
_delay_us(20000-2500);
}
}
void go_slow(char times){
// does one slow leek down/up
// beat is 500ms
for (char i=0;i<times;i++){
go_low();
_delay_ms(10);
go_high();
_delay_ms(290);
PORTA^=(1<<PA2);
PORTA^=(1<<PA3);
}
}
void go_fast(char times){
// does one fast leek down/up
// beat is 250ms
for (char i=0;i<times;i++){
go_low();
_delay_ms(10);
go_high();
_delay_ms(15);
PORTA^=(1<<PA2);
PORTA^=(1<<PA3);
}
}
void head_left(){
// tilts the head to the left
for (char i=0;i<5;i++){
PORTA|=(1<<PA1);
_delay_us(1330);
PORTA&=~(1<<PA1);
_delay_us(20000-1200);
}
}
void head_right(){
// tilts the head to the right
for (char i=0;i<5;i++){
PORTA|=(1<<PA1);
_delay_us(1500);
PORTA&=~(1<<PA1);
_delay_us(20000-1200);
}
}
void head_center(){
// centers the head
for (char i=0;i<5;i++){
PORTA|=(1<<PA1);
_delay_us(1400);
PORTA&=~(1<<PA1);
_delay_us(20000-1200);
}
}
void head_go(char times){
// rocks the head back and forth once
for (char i=0;i<(times-1);i++){
head_left();
_delay_ms(400);
PORTA^=(1<<PA2);
PORTA^=(1<<PA3);
head_right();
_delay_ms(400);
PORTA^=(1<<PA2);
PORTA^=(1<<PA3);
}
head_center(); // returns head to center when done
_delay_ms(400);
PORTA^=(1<<PA2);
PORTA^=(1<<PA3);
}
int main(void) {
while (1){
DDRA=255; // set port A (servos) as outputs
DDRB=0; // set port B (listening pins) as inputs
go_lowest();head_center();// set starting positions
while ((PINB & _BV(PB0))){} // wait for beep que
PORTA=(1<<PA3);
go_high();_delay_ms(1000);
while ((PINB & _BV(PB0))){} // wait for beep que
go_slow(31); // tilt leek slowly 31 times
while ((PINB & _BV(PB0))){} // wait for beep que
go_slow(31); // tilt leek slowly 31 times
while ((PINB & _BV(PB0))){} // wait for beep que
_delay_ms(200);
head_go(16); // rock head 16 times
while ((PINB & _BV(PB0))){} // wait for beep que
go_fast(68); // tilt leek rapidly 68 times
while ((PINB & _BV(PB0))){} // wait for beep que
go_slow(24); // tilt leek slowly 24 times
while ((PINB & _BV(PB0))){} // wait for beep que
go_fast(17); // tilt leek rapidly 17 times
while ((PINB & _BV(PB0))){} // wait for beep que
go_slow(31); // tilt leek slowly 31 times
while ((PINB & _BV(PB0))){} // wait for beep que
go_slow(31); // tilt leek slowly 31 times
while ((PINB & _BV(PB0))){} // wait for beep que
_delay_ms(200);
head_go(16); // rock head 16 times
go_lowest(); // reset position
PORTA=0;
}
return 0;
}
Finally, I'd like to take a moment to indicate one of the reasons this project is special to me. My wife, Angelina Harden, died one year ago today. This project was the last one she worked on with me. She died a few days after the video was taken, and in the process of moving out of our apartment I threw away almost everything (including this project). Although I never finished it, I remember working on it with Angelina - we went to wal-mart together to buy the foam board I used to make it, and she told me that I should make her head rock back and forth rather than just move her arm. I remember that, once it was all done, I let her sit in the chair in front of it and played it through, and she laughed nearly the whole time :) I'll always miss her.
---
title: Geek Spin - ATTiny44 Project Prototype
date: 2012-08-18 15:28:38
tags: microcontroller, old
---
# Geek Spin - ATTiny44 Project Prototype
__Some days you feel like working on projects to benefit humanity. The day I made this clearly wasn't one of those days.__ A little over a year ago, I got into a troll war with my friend [Mike Seese](http://www.mikeseese.com/). The joke, similar to that of [rick rolling](http://www.youtube.com/watch?v=oHg5SJYRHA0), was to get each other to unexpectedly click a link to the [Hatsune Miku version of the leekspin song](http://www.youtube.com/watch?v=kbbA9BhCTko&feature=player_embedded). After several weeks of becoming beyond annoying, I decided to make an _actual_ Hatsune Miku which would spin her leek and bobble her head to the techno version of the [Levan Polka](http://www.youtube.com/watch?v=1ygdAiDxKfI) for his birthday.
<div class="text-center img-border">
</div>
__The goal was to create a minature Miku which would perform perfectly in sync with audio coming from a portable music player (iPod or something) and _NOT_ require a computer connection.__ I accomplished it by sending some creative control beeps out of the left channel of the stereo signal. Although I didn't finish the project, I got pretty far with the prototype, so I decided to dig it out of the archives and share it with the world because it's pretty entertaining!
(look how close I came to replicating the original:
__How did I do it?__ First off, I used servos. If you're not familiar with them, I suggest you look up [how servos work](http://www.servocity.com/html/how_do_servos_work_.html). Perhaps check out [how to control servos with AVR microcontrollers](http://www.engineersgarage.com/embedded/avr-microcontroller-projects/atmega16-servo-motor-circuit). Basically, their position along a rotational axis is determined by the width of a pulse on a 20ms time window. Anyhow, if I only had 1 servo to control (i.e., leek only), I'd have controlled the servo directly with PWM signals in the left channel - no microcontroller needed, easy as pie, problem solved. However, since I needed to control two servos, I had to come up with something a bit more creative. Although I could have probably done this ten different ways, the way I chose to do it was using a series of pre-encoded leek spin and head bobble motions, triggered by control beeps in the left channel of the audio cable. (The right channel was patched through to the speakers.) Below is a diagram of what I believe I did, although I didn't thoroughly document it at the time, so you might have to use your imagination if you decide to re-create this project.
<div class="text-center img-border">
</div>
__The idea is that by sending bursts of sine waves,__ the circuit can rectify them and smooth them out to have them look to a microcontroller like a brief "high" signal. Each signal would tell the microcontroller to proceed to the next pre-programmed (and carefully timed) routine. With enough practice listening, watching, and tweaking the code, I was able to make a final version which worked pretty darn well!
<div class="text-center img-border">
</div>
__LISTEN__ to the [music with control beeps](http://www.SWHarden.com/blog/images/2012/08/GOLEEKGO.mp3) (it's a surprisingly fun listen)
__A few technical details__ are that I used an ATTiny44a microcontroller (it may have been an ATTiny2313, I can't remember for sure, but they're so similar it's virtually negligable). The servos I used were cheap (maybe $4?) from eBay. They looked like the one pictured below. The servo position was controlled by PWM, but I manually sent the pulses and didn't actually use the integrated PWM in the microcontroller. I can't remember why I did it this way - perhaps because it was so simple to use the _delay_us() and _delay_ms() functions? I also used an operational amplifier (if I remember, it was a LM741) to boost the left channel control signals rather than rectifying/assessing the left channel directly.
<div class="text-center img-border img-micro">
[](01_findpic.png)
[](02_dropbg.jpg)
[](08_hairtop.jpg)
[](06_blockskirt.jpg)
[](body.png)
[](hairtop.png)
</div>
[This is the video](https://www.youtube.com/embed/kbbA9BhCTko) which I mimiced to create my prototype (note how the leek in her arm and her head move exactly the same as the prototype I made - score!)
__And how did I find out about this song?__ I actually saw it on the video below which was hosted on wimp.com. I thought the song was catchy, looked it up, and the rest was history. It's worth noting that (perhaps to avoid copyright issues?) the key was shifted two half-steps up. I get a kick out of the way the girl waves her arm in the beginning, mimicking the leek :)
__Here are some of the images I made__ which I printed, glued to foam board, and cut out with a razor blade. I'm not sure how useful they are, but they're provided just in case.
... but sometimes Japan takes it a bit too far and things get awkward ...
__Below is the code I used.__ Note that PWM that controls the servos isn't the integrated PWM, but rather a couple pins I manually pulse on and off to control the arm and head positions. Also notice how, in the main routine, I wait for the control beeps before continuing the next sequences.
```c
// leek spin code - designed for ATTiny
// by Scott Harden, www.SWHarden.com
#include <avr/io.h>
#include <avr/delay.h>
void go_high(){
// sets the arm to the highest position
for (char i=0;i<5;i++){
PORTA|=(1<<PA0);
_delay_us(1400);
PORTA&=~(1<<PA0);
_delay_us(20000-1200);
}
}
void go_low(){
// sets the leek to the middle position
for (char i=0;i<5;i++){
PORTA|=(1<<PA0);
_delay_us(1900);
PORTA&=~(1<<PA0);
_delay_us(20000-1900);
}
}
void go_lowest(){
// sets the leek to the lowest position
for (char i=0;i<5;i++){ // takes 100ms total
PORTA|=(1<<PA0);
_delay_us(2300);
PORTA&=~(1<<PA0);
_delay_us(20000-2500);
}
}
void go_slow(char times){
// does one slow leek down/up
// beat is 500ms
for (char i=0;i<times;i++){
go_low();
_delay_ms(10);
go_high();
_delay_ms(290);
PORTA^=(1<<PA2);
PORTA^=(1<<PA3);
}
}
void go_fast(char times){
// does one fast leek down/up
// beat is 250ms
for (char i=0;i<times;i++){
go_low();
_delay_ms(10);
go_high();
_delay_ms(15);
PORTA^=(1<<PA2);
PORTA^=(1<<PA3);
}
}
void head_left(){
// tilts the head to the left
for (char i=0;i<5;i++){
PORTA|=(1<<PA1);
_delay_us(1330);
PORTA&=~(1<<PA1);
_delay_us(20000-1200);
}
}
void head_right(){
// tilts the head to the right
for (char i=0;i<5;i++){
PORTA|=(1<<PA1);
_delay_us(1500);
PORTA&=~(1<<PA1);
_delay_us(20000-1200);
}
}
void head_center(){
// centers the head
for (char i=0;i<5;i++){
PORTA|=(1<<PA1);
_delay_us(1400);
PORTA&=~(1<<PA1);
_delay_us(20000-1200);
}
}
void head_go(char times){
// rocks the head back and forth once
for (char i=0;i<(times-1);i++){
head_left();
_delay_ms(400);
PORTA^=(1<<PA2);
PORTA^=(1<<PA3);
head_right();
_delay_ms(400);
PORTA^=(1<<PA2);
PORTA^=(1<<PA3);
}
head_center(); // returns head to center when done
_delay_ms(400);
PORTA^=(1<<PA2);
PORTA^=(1<<PA3);
}
int main(void) {
while (1){
DDRA=255; // set port A (servos) as outputs
DDRB=0; // set port B (listening pins) as inputs
go_lowest();head_center();// set starting positions
while ((PINB & _BV(PB0))){} // wait for beep que
PORTA=(1<<PA3);
go_high();_delay_ms(1000);
while ((PINB & _BV(PB0))){} // wait for beep que
go_slow(31); // tilt leek slowly 31 times
while ((PINB & _BV(PB0))){} // wait for beep que
go_slow(31); // tilt leek slowly 31 times
while ((PINB & _BV(PB0))){} // wait for beep que
_delay_ms(200);
head_go(16); // rock head 16 times
while ((PINB & _BV(PB0))){} // wait for beep que
go_fast(68); // tilt leek rapidly 68 times
while ((PINB & _BV(PB0))){} // wait for beep que
go_slow(24); // tilt leek slowly 24 times
while ((PINB & _BV(PB0))){} // wait for beep que
go_fast(17); // tilt leek rapidly 17 times
while ((PINB & _BV(PB0))){} // wait for beep que
go_slow(31); // tilt leek slowly 31 times
while ((PINB & _BV(PB0))){} // wait for beep que
go_slow(31); // tilt leek slowly 31 times
while ((PINB & _BV(PB0))){} // wait for beep que
_delay_ms(200);
head_go(16); // rock head 16 times
go_lowest(); // reset position
PORTA=0;
}
return 0;
}
```
__Finally, I'd like to take a moment to indicate one of the reasons this project is special to me.__ My wife, Angelina Harden, died one year ago today. This project was the last one she worked on with me. She died a few days after the video was taken, and in the process of moving out of our apartment I threw away almost everything (including this project). Although I never finished it, I remember working on it with Angelina - we went to wal-mart together to buy the foam board I used to make it, and she told me that I should make her head rock back and forth rather than just move her arm. I remember that, once it was all done, I let her sit in the chair in front of it and played it through, and she laughed nearly the whole time :) I'll always miss her.
