TouchDesigner & Arduino

You can use Arduino to send (sensor) data to TouchDesigner and vice versa.

For example, you might want to measure the light condition of a room and use this data to trigger something in TouchDesigner. Or you might want to be able to have a light bulb react to a sound file, or a motor spin in sync with a projection.
To do so there are typically to methods that can be used:

• Firmata

• Serial Communication

With this method you are making Arduino & TD talk to each other by using Serial, a communication protocol that is able to send info essentially through a wire (the usb wire that connect the board to the computer running TD). TD has a Serial DAT operator that is able to receive this data.
This method is preferred when your Arduino needs to use library or specific code to gather data from the sensors you are using.

Using Serial Communication

Serial communication is a method for transferring data between devices. It is able to send data sequentially over a wire. In this case the USB cable that connects your Arduino with the computer running TD.
For this example we are getting sensor data from a LDR and a Ultrasonic sensor, sensing light values and distance.

Arduino to TouchDesigner

Arduino wiring and code

First we wire the sensors to Arduino and upload the code to the board. The following example uses a LDR (light sensor) and an Ultrasonic sensor (distance sensor).
Here is the code:

 
//LDR PIN and VARIABLE
int sensorPin = A0; // select the input pin for LDR
int sensorValue = 0; // variable to store the value coming from the sensor
//ULTRASONIC SENSOR PIN and VARIABLEs
const int trigPin = 2;
const int echoPin = 3;
long duration;
int distance;

void setup() {
  //start serial communication
  Serial.begin(9600); //sets serial port for communication
 
 //define ultrasonic sensor pin as in or out 
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT); // Sets the echoPin as an Input
}

void loop() {
  //getting sensor data from LDR 
      sensorValue = analogRead(sensorPin); // read the value from the sensor

  //getting sensor data from ultrasonic sensor 
      // Clears the trigPin
      digitalWrite(trigPin, LOW);
      delayMicroseconds(2);
      // Sets the trigPin on HIGH state for 10 micro seconds
      digitalWrite(trigPin, HIGH);
      delayMicroseconds(10);
      digitalWrite(trigPin, LOW);
      // Reads the echoPin, returns the sound wave travel time in microseconds
      duration = pulseIn(echoPin, HIGH);
      // Calculating the distance
      distance = duration * 0.034 / 2;
      
   // Prints and sends the LDR and distance sensor values on the serial monitor on two separate lines 
      Serial.print(sensorValue); 
      Serial.print(" "); 
      Serial.println(distance);
}

We are initializing