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The ET is an open source project under the Creative Commons License.

The ET is currently manufactured on a not for profit basis by Creative Robotics Ltd. If you are interested in purchasing a device please contact Bill Bigge: bill@creative-robotics.com

The Enactive Torch

The Enactive Torch – Version 3.0

The ET a hand held device with distance sensors at one end and a vibrating motor that can be strapped to your wrist. The intensity of the vibration is lined to the distance of objects in front of the torch. It uses an Arduino pro-mini so it is totally user programmable and it includes a Sparkfun BlueSMiRF Gold bluetooth transmitter and a triple axis accelerometer so that data on usage can be logged remotely. Power comes from six AAA batteries and there is a charging socket so it can be recharged without removing the batteries. The vibrating motor can be fitted externally or internally, although an internal vibrating motor can interfere with accelerometer readings. The following page details some technical information about the ET and a source code listing for the Arduino controller.

Circuit Schematic:


ET Schematic

The schematic is also included in the instructions:

Enactive Torch Instructions (PDF)

Arduino source Code:

//global variables
int Sensor1, Sensor2;
int AccX, AccY, AccZ;
int MotorValue = 0;
int ToneFrequency = 500;

//pin input and output constants
const int MotorOutputPin = 9; //digital pin 4 – PWM OUTPUT
const int SpeakerPin = 4; //digital pin 4 – OUTPUT
const int ButtonPin = 8; //digital pin 8 – INPUT
const int GreenLED = 7; //digital pin 7 – OUTPUT
const int Sensor1Pin = 1; //analog input pin 1 – Long range sensor 20-150cm
const int Sensor2Pin = 2; //analog input pin 2 – Short range sensor 8-80cm
const int AccXPin = 5; //analog input pin 5
const int AccYPin = 4; //analog input pin 4
const int AccZPin = 3; //analog input pin 3
X axis is along the length of the ET
Y axis across the width
Z axis from bottom to top

//a high voltage on the LED pin switches it off
#define LEDON LOW

void setup()

//set up the digital inputs and outputs
pinMode(SpeakerPin, OUTPUT);
pinMode(ButtonPin, INPUT);
pinMode(GreenLED, OUTPUT);


void loop()

This code takes data from the long range (20-150cm) sensor only
and maps it to the motor which has a vibration intensity range of 0-255
All sensor data including accelerometers is printed over the serial port.
The sensor reading is also mapped to the speaker if the button is pressed
(closer = higher pitch) and the LED lights up when the button is pressed.

The USB programmer will only work when the device is switched OFF
The arduino Pro-mini can draw power from the USB programmer but if
the ET is switched ON when the programmer is inserted then there is a conflict
between the USB programmer and the bluetooth device
(Both share the same Tx and RX pins on the arduino)
This means that the sensors are OFF when the device is communicating over USB
and consequently any sensor data will be garbage.
The speaker is powered by the arduino so it will work with the programmer attached
Sensor1 = analogRead(Sensor1Pin);
// wait 10 milliseconds for the analog-to-digital converter
// to settle after the last reading:
Sensor2 = analogRead(Sensor2Pin);
AccX = analogRead(AccXPin);
AccY = analogRead(AccYPin);
AccZ = analogRead(AccZPin);

MotorValue = map(Sensor1, 0, 600, 0, 255);
analogWrite(MotorOutputPin, MotorValue);

// print the sensor data and accellerometer values:

//Map the sensor reading to the speaker if the button is pressed
//illuminate the Green LED if the button is pressed

ToneFrequency = map(Sensor1, 0, 600, 32, 1046);
tone(SpeakerPin, ToneFrequency);
digitalWrite(GreenLED, LEDON);


digitalWrite(GreenLED, LEDOFF);


void playTone()

//play a quick tune on startup
digitalWrite(GreenLED, LEDON);
tone(SpeakerPin, 392); //Start with a tone
tone(SpeakerPin, 440); //Up a full tone
tone(SpeakerPin, 349); //Down a major third
tone(SpeakerPin, 174); //Now drop an octave
tone(SpeakerPin, 261); //Up a perfect fifth
digitalWrite(GreenLED, LEDOFF);


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