Gabriella Levine

ongoing and past work
sensors

Documentation of Sneel_002

Soon I will make a how-to guide for Sneel_002 on instructables.com, as I did for the first version of Sneel, (i’m working on that) but until then…

Sneel swam in central park

The hardware:

Like a real snakes vertebrates:

I used Arduino Mega with multiple servos attached, using multiple 6V NiMh battery packs, placed along the body, with an xbee mounted on top to control three parameters of wave behavior: period, wavelength, and amplitude.

I taped the bottom of the Arduino so nothing shorted:

First I stuffed the arduino + xbee into a waterproof sac:

Then I decided that was overkill so I just stuffed everything into the tube (as I had sealed each servo motor with epoxy and had a water tight seal on the tube top and bottom)

See the waterproofed servos:

See wires etc. stuffed in the tube:

The Software:

A diagram of the control firmware and the relationship between the classes:

I wrote an Arduino library called ServoWave to control period, amplitude and wavelength of the oscillation for Sneel’s swimming behavior.

Here is it on github.

See how each servo motor oscillates – in the following graph, I print out values of each servo as each motor rotates in a sine wave slightly out of phase from each other. The x axis is time and the y axis is angle, and each colored line is a different motor.

After getting everything packed up in the tube, I tested Sneel_002 on the floor of ITP.

He seemed sort of real:

Sneel in the wild:

Well, Sneel_002 swam pretty well, sort of like a real snake, but there’s much work to be done…

Model shot:

Protei in Ars

Protei got an honorary mention in Ars Electronica!

Protei on Wired!

we got on wired!
“Designing Sailboats to Mop Up Oil Spills”

bellflower voltage logging solar panel

logging voltage here: http://www.levinegabriella.com/bellflower/bellflower_dataLog.txt

arduino code here:

https://github.com/gabriella/bellflower

php and more to come…

tmp36

I’ve switched over to this sensor as a solid state temperature sensor:
I will use thermocouples for rapid rate of changes of liquids but for environmental sensing:

from adafruit:

temperature from tmp36 sensor: http://www.ladyada.net/learn/sensors/tmp36.html

0.73 volts
22.75 degrees C
72.96 degrees F
0.73 volts

//TMP36 Pin Variables
int sensorPin = 0; //the analog pin the TMP36's Vout (sense) pin is connected to
//the resolution is 10 mV / degree centigrade with a
//500 mV offset to allow for negative temperatures

/*
* setup() - this function runs once when you turn your Arduino on
* We initialize the serial connection with the computer
*/
void setup()
{
Serial.begin(9600); //Start the serial connection with the computer
//to view the result open the serial monitor
}

void loop() // run over and over again
{
//getting the voltage reading from the temperature sensor
int reading = analogRead(sensorPin);

// converting that reading to voltage, for 3.3v arduino use 3.3
float voltage = reading * 5.0;
voltage /= 1024.0;

// print out the voltage
Serial.print(voltage); Serial.println(" volts");

// now print out the temperature
float temperatureC = (voltage - 0.5) * 100 ; //converting from 10 mv per degree wit 500 mV offset
//to degrees ((volatge - 500mV) times 100)
Serial.print(temperatureC); Serial.println(" degrees C");

// now convert to Fahrenheight
float temperatureF = (temperatureC * 9.0 / 5.0) + 32.0;
Serial.print(temperatureF); Serial.println(" degrees F");

delay(1000); //waiting a second
}

IR proximity sensor

Here’s the Sharp product i’m using: http://www.sparkfun.com/datasheets/Sensors/Infrared/gp2y0a02yk_e.pdf
bought from here: http://www.sparkfun.com/products/8958

This code is simply smoothing an analog input value (0-5V), and it seems to work ok, but I have to see – I’m working on graphing the values (using Excel and CoolTerm) to make sure that my linearizing function I got from here: http://www.acroname.com/robotics/info/articles/irlinear/irlinear.html = has worked correctly

const int numReadings = 100;

int readings[numReadings]; // the readings from the analog input
int index = 0; // the index of the current reading
int total = 0; // the running total
int average = 0; // the average

int inputPin = A0;

void setup()
{
// initialize serial communication with computer:
Serial.begin(9600);
// initialize all the readings to 0:
for (int thisReading = 0; thisReading < numReadings; thisReading++)
readings[thisReading] = 0;
}

void loop() {
// subtract the last reading:
total= total - readings[index];
// read from the sensor:
readings[index] = analogRead(inputPin);
// add the reading to the total:
total= total + readings[index];
// advance to the next position in the array:
index = index + 1;

// if we're at the end of the array...
if (index >= numReadings)
// ...wrap around to the beginning:
index = 0;

// calculate the average:
average = total / numReadings;
// send it to the computer as ASCII digits
Serial.println(average);
}

This code also is seems good but I have to check it out more closely:

int sensorPin = 0; // input pin for the sensor
int barPin[] = {2, 3, 4, 5, 6, 7, 8, 9, 10, 11};
int barPinCount = 10;
int volt = 0; // variable to store the value coming from the sensor
int zeit = 100; // *10 = Gesamtzeit - total time

void setup() {
Serial.begin(9600);
int thisPin;
// the array elements are numbered from 0 to (pinCount - 1).
// use a for loop to initialize each pin as an output:
for (int thisPin = 0; thisPin < barPinCount; thisPin++) {
pinMode(barPin[thisPin], OUTPUT);
}
}

void loop() {
int volt = 0;
for(int i=0; i<10; i++)
{
volt += analogRead(sensorPin);
delay(zeit);
}
volt /= 10;

Serial.println(volt);
int litCount = 0;
if (volt <= 82) {
// >= 80cm
litCount = 1;
} else if (volt <= 92) {
// >= 70cm
litCount = 2;
} else if (volt <= 102) {
// >= 60cm
litCount = 3;
} else if (volt <= 123) {
// >= 50cm
litCount = 4;
} else if (volt <= 154) {
// >= 40cm
litCount = 5;
} else if (volt <= 184) {
// >= 30cm
litCount = 6;
} else if (volt <= 266) {
// >= 20cm
litCount = 7;
} else if (volt <= 328) {
// >= 15cm
litCount = 8;
} else if (volt <= 461) {
// >= 10cm
litCount = 9;
} else if (volt > 461) {
// < 10cm
litCount = 10;
}

for(int b=0; b<10; b++)
{
if(b<=litCount)
digitalWrite(barPin[b], HIGH); // Turn the bar on
else
digitalWrite(barPin[b], LOW); // Turn the bar off
}

}

circuit – SHT11 humidity sensor

I found a super nice library – https://github.com/practicalarduino/SHT1x – it’s working way better than what I had going before – Thanks!

I’m using this schematic: using this http://www.parallax.com/dl/docs/prod/acc/SensirionDocs.pdf

I’m getting legible values :

Temperature: 25.4199981689C / 77.8459930419F. Humidity: 23.45%
Temperature: 25.4399948120C / 77.8639984130F. Humidity: 23.45%
Temperature: 25.4799957275C / 77.7919921875F. Humidity: 25.12%
Temperature: 25.4599990844C / 77.8999938964F. Humidity: 27.65%
Temperature: 25.3600006103C / 77.7739944458F. Humidity: 27.87%
Temperature: 25.5199966430C / 77.9719924926F. Humidity: 26.86%

circuit – 2 axis parallax accelerometer

This is on the arduino side:

int pinX = 3;
int pinY = 2;
unsigned long serialTimer = millis();
unsigned long xAcc = 0;
unsigned long yAcc = 0;
boolean flipflop;

void setup()
{
pinMode(pinX, INPUT);
pinMode(pinY, INPUT);
Serial.begin(115200);
}

void loop()
{
if (flipflop == true) {
xAcc = pulseIn(pinX, HIGH);
flipflop = false;
} else {
yAcc = pulseIn(pinY, HIGH);
flipflop = true;
}

if ((millis() - serialTimer) > 50 ) {
Serial.print("X ");
Serial.println(xAcc);
// Serial.print(" ");
Serial.print("Y ");
Serial.println(yAcc);
}
}

to visualize it:
in processing:

import processing.serial.*;

Serial port; // Create object from Serial class
int val; // Data received from the serial port
int xAngle;
int yAngle;

void setup()
{
println ( Serial.list());
size(200, 200,P3D);
frameRate(10);
// Open the port that the board is connected to and use the same speed (9600 bps)
port = new Serial(this, Serial.list()[0],115200);
port.bufferUntil(13);
lights();

}

void draw()
{
background(0);
directionalLight(51, 102, 126, 0, 0, -1);
translate(100,100,0);
rotateX(map(xAngle,3800,6300,-1 * HALF_PI,HALF_PI));
rotateY(map(yAngle,3800,6300,-1 * HALF_PI,HALF_PI));
translate(-50,-50,0);
rect(0,0,100,100);

}

void serialEvent(Serial p) {
String msg = port.readStringUntil(13);
if (msg != null) readMsg(msg);

}

void readMsg(String msg) {

//remove non printing chars
int badChars = 0;
for (int i = msg.length() -1; i >= 0; i--) {
char c = msg.charAt(i);
if ( c == 10 || c ==13) {
badChars++;
}
}
if (badChars > 0) msg = msg.substring(0,msg.length()-badChars+1);

String[] words = splitTokens(msg);
if (words[0].equals("X")) {

xAngle = int( words[1]);
}
if (words[0].equals("Y")) {
yAngle = int( words[1]);
}

}