Gesture Controlled Soft Robot Tentacle

Made by blight3d28 / 3D Printing / Robotics

About the project

A soft robot controlled with a wrist mounted accelerometer.

Project info

Difficulty: Moderate

Platforms: Adafruit, Seeed Studio

Estimated time: 6 days

License: GNU General Public License, version 3 or later (GPL3+)

Items used in this project

Hardware components

	coin cell holder	x 1
	Coin Cell Battery CR2032	x 2
	dragonskin 10	x 1
	ecoflex 00-30	x 1
	Adafruit Silicone tube You need 6 tubes, but their long enough that you can cut each one in half.	x 3
	Seeed Studio Grove - 2-Channel SPDT Relay I used 6 single channel relays.	x 3
	Adafruit air valves	x 3
	Adafruit air pumps	x 3
	Arduino Nano 33 BLE Sense	x 2

View all

Hand tools and fabrication machines

	Soldering iron (generic)	x 1
	3D Printer (generic)	x 1

Story

I wanted to make a simple soft robot. The soft robot has 3 chambers inflated by air pumps. Once made I created a small wrist mounted accelerometer (Arduino nano 33 ble sense), to control the movements of the tentacle in a fun way. The tentacle mold was made with a mixture of ecoflex 00-30 & dragonskin 10 (ecoflex 00-50 may be enough, so that the cost goes down..... but it wasn't tested). The air pumps & the the air valves are all controlled with one relay each (making that part of the code super simple).

Schematics, diagrams and documents

Sketch

CAD, enclosures and custom parts

Watch case

A watch case, you need a nano 33 ble without pins & a power source (I used 2 coin cell battery holder from adafruit) use small screws to hold everything to the 3d printed case. I used nylon straps for the wrist part.

Go to download

inner design_mold_tentace

This forms the inner ridges in the silicone tentacle. Fit the sticks one by one in the triangle & solder them together.

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Tentacle mold

Tentacle mold (print 3 times) screw them together, once the silicone is mixed insert the inner design parts & slowly pour the silicone.

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Air pump/air valve cases

Case for the adafruit air pumps & air valves.

Go to download

V2 tentacle mold

A second version of the tentacle mold (cut in half, easier to print, print at different times). Need to print both pieces (top & bottom pieces 3 times each). After, solder top and bottom piece together.

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Tentacle base

The base of the tentacle, solder the two pieces together. Once your silicone tentacle has been made, put some silicone on the 3 circles and press the tentacle together with the pla. 3 small square holes in the bigger piece are for you to feed the air tubes through. The bottom of the smaller piece contains a small tube for you to connect the air tube to.

Go to download

Code

Transmitter

Simply a arduino nano 33 ble sense.

#include <ArduinoBLE.h> #include <Arduino_LSM9DS1.h> const char* deviceServiceUuid = "19b10000-e8f2-537e-4f6c-d104768a1214"; const char* deviceServiceCharacteristicUuid = "19b10001-e8f2-537e-4f6c-d104768a1214"; const int R_LED_PIN = 22; const int G_LED_PIN = 23; const int B_LED_PIN = 24; long tiempo_prev = 0; float pitch_prev = 0; float roll_prev = 0; // Sensibilidad del giroscopio 2000 dps -> 70 // Sensibilidad del acelermetro 4g -> 0.122 const float A_S = 0.122; const float G_S = 70.0; void setup() { Serial.begin(9600); setColor("RED"); if (!IMU.begin()) { //Serial.println("Failed to initialize IMU!"); while (1); } // begin ble initialization if (!BLE.begin()) { //Serial.println("starting BLE failed!"); while (1); } //Serial.println("BLE Central - gesture control"); } void loop() { connectToPeripheral(); } void connectToPeripheral(){ BLEDevice peripheral; do { // start scanning for peripherals BLE.scanForUuid(deviceServiceUuid); peripheral = BLE.available(); } while (!peripheral); if (peripheral) { // discovered a peripheral, print out address, local name, and advertised service //Serial.print("Found "); //Serial.print(peripheral.address()); //Serial.print(" '"); //Serial.print(peripheral.localName()); //Serial.print("' "); //Serial.print(peripheral.advertisedServiceUuid()); //Serial.println(); // stop scanning BLE.stopScan(); controlPeripheral(peripheral); } } void controlPeripheral(BLEDevice peripheral) { // connect to the peripheral //Serial.println("Connecting ..."); if (peripheral.connect()) { //Serial.println("Connected"); setColor("BLUE"); } else { //Serial.println("Failed to connect!"); return; } // discover peripheral attributes //Serial.println("Discovering attributes ..."); if (peripheral.discoverAttributes()) { //Serial.println("Attributes discovered"); } else { //Serial.println("Attribute discovery failed!"); peripheral.disconnect(); return; } BLECharacteristic gestureCharacteristic = peripheral.characteristic(deviceServiceCharacteristicUuid); if (!gestureCharacteristic) { //Serial.println("Peripheral does not have gesture characteristic!"); peripheral.disconnect(); return; } else if (!gestureCharacteristic.canWrite()) { //Serial.println("Peripheral does not have a writable gesture characteristic!"); peripheral.disconnect(); return; } while (peripheral.connected()) { String command = calculoAngulos(); //Serial.print("comando: "); //Serial.println(command); if (command != "") { setColor("PURPLE"); int n = command.length(); // declaring character array char char_array[n + 1]; // copying the contents of the string to char array strcpy(char_array, command.c_str()); gestureCharacteristic.writeValue((const char*)char_array); delay(1); } } //Serial.println("Peripheral disconnected!"); } String calculoAngulosConFiltroComplementario() { float ax, ay, az; float gx, gy, gz; float pitch,_pitch; float roll,_roll; float dt; String _command = ""; if (IMU.accelerationAvailable()) { IMU.readAcceleration(ax, ay, az); } if (IMU.gyroscopeAvailable()) { IMU.readGyroscope(gx, gy, gz); } // Ratios ax = ax/A_S; ay = ay/A_S; az = az/A_S; gx = gx/G_S; gy = gy/G_S; gz = gz/G_S; dt = (millis() - tiempo_prev) / 1000.0; tiempo_prev = millis(); // Calcular los ngulos con el acelerometro _pitch = atan2(ax, sqrt(ay*ay + az*az)); _roll = atan2(ay, sqrt(ax*ax + az*az)); // Convertimos de radianes a grados _pitch *= (180.0 / PI); _roll *= (180.0 / PI); // Aplicar el filtro complementario pitch = 0.98*(pitch_prev + gx*dt) + (0.02*_pitch); roll = 0.98*(roll_prev + gy*dt) + (0.02*_roll); //Serial.print(F("Rotacion en X: ")); //Serial.print(pitch); //Serial.print(F("\t Rotacion en Y: ")); //Serial.println(roll); pitch_prev = pitch; roll_prev = roll; _command = String(pitch, DEC) + "," + String(roll, DEC); return _command; } String calculoAngulos() { float ax, ay, az; float gx, gy, gz; float pitch,roll; String _command = ""; if (IMU.accelerationAvailable()) { IMU.readAcceleration(ax, ay, az); } // Calcular los ngulos con el acelerometro pitch = atan2(ax, sqrt(ay*ay + az*az)); roll = atan2(ay, sqrt(ax*ax + az*az)); // Convertimos de radianes a grados pitch *= (180.0 / PI); roll *= (180.0 / PI); Serial.print(F("Rotacion en X: ")); Serial.print(pitch); Serial.print(F("\t Rotacion en Y: ")); Serial.println(roll); _command = String(pitch, DEC) + "," + String(roll, DEC); return _command; } void setColor(String color) { if (color == "RED") { digitalWrite(R_LED_PIN, LOW); // High values -> lower brightness digitalWrite(G_LED_PIN, HIGH); digitalWrite(B_LED_PIN, HIGH); }else if (color == "GREEN") { digitalWrite(R_LED_PIN, HIGH); // High values -> lower brightness digitalWrite(G_LED_PIN, LOW); digitalWrite(B_LED_PIN, HIGH); }else if (color == "BLUE") { digitalWrite(R_LED_PIN, HIGH); // High values -> lower brightness digitalWrite(G_LED_PIN, HIGH); digitalWrite(B_LED_PIN, LOW); }else if (color == "PURPLE") { digitalWrite(R_LED_PIN, LOW); // High values -> lower brightness digitalWrite(G_LED_PIN, HIGH); digitalWrite(B_LED_PIN, LOW); } }

Receiver

An arduino nano 33 ble sense, with 3 air pumps & 3 air valves

#include <ArduinoBLE.h> const int R_LED_PIN = 22; const int G_LED_PIN = 23; const int B_LED_PIN = 24; int relay7SOLELEFT = 7; int relay10PUMPLEFT = 10; int relay8SOLEMIDDLE = 8; int relay11PUMPMIDDLE = 11; int relay9SOLERIGHT = 9; int relay12PUMPRIGHT = 12; const char* deviceServiceUuid = "19b10000-e8f2-537e-4f6c-d104768a1214"; const char* deviceServiceCharacteristicUuid = "19b10001-e8f2-537e-4f6c-d104768a1214"; String command = ""; static int dutyX = 0; static int dutyY = 0; static int duty1 = 0; static int duty2 = 0; // BLE gesture Service BLEService gestureService(deviceServiceUuid); // BLE gesture Switch Characteristic BLEStringCharacteristic gestureCharacteristic(deviceServiceCharacteristicUuid, BLERead | BLEWrite,512); void setup() { Serial.begin(9600); pinMode(relay7SOLELEFT, OUTPUT); pinMode(relay10PUMPLEFT, OUTPUT); pinMode(relay8SOLEMIDDLE, OUTPUT); pinMode(relay11PUMPMIDDLE, OUTPUT); pinMode(relay9SOLERIGHT, OUTPUT); pinMode(relay12PUMPRIGHT, OUTPUT); // begin ble initialization if (!BLE.begin()) { Serial.println("starting BLE "); while (1); } // set advertised local name and service UUID: BLE.setLocalName("Mini Robot 4x4 peripheral"); BLE.setAdvertisedService(gestureService); // add the characteristic to the service gestureService.addCharacteristic(gestureCharacteristic); // add service BLE.addService(gestureService); // set the initial value for the characeristic: gestureCharacteristic.writeValue(""); // start advertising BLE.advertise(); //Serial.println("Mini Robot 4x4 peripheral"); setColor("GREEN"); } void loop() { // listen for BLE peripherals to connect: BLEDevice central = BLE.central(); // if a central is connected to peripheral: if (central) { //Serial.print("Connected to central: "); // print the central's MAC address: //Serial.println(central.address()); // while the central is still connected to peripheral: while (central.connected()) { // if the remote device wrote to the characteristic, if (gestureCharacteristic.written()) { command = gestureCharacteristic.value(); Serial.print(F("commmand value: ")); Serial.println(command); sendInstruction(command); } } // when the central disconnects, print it out: //Serial.print(F("Disconnected from central: ")); //Serial.println(central.address()); } } void sendInstruction(String str) { if (str.length() == 0) return; // split int pos = str.indexOf(","); int strLength = str.length(); dutyX = str.substring(0,pos).toInt(); dutyY = str.substring(pos+1,strLength).toInt(); Serial.print(F("valor en X: ")); Serial.print(dutyX); Serial.print(F("\t valor en Y: ")); Serial.println(dutyY); if ((dutyY >= 30) && (dutyX > -20) && (dutyX < 20)) // left { digitalWrite(relay9SOLERIGHT, HIGH); digitalWrite(relay12PUMPRIGHT, HIGH); digitalWrite(relay7SOLELEFT, LOW); digitalWrite(relay10PUMPLEFT, LOW); digitalWrite(relay8SOLEMIDDLE, LOW); digitalWrite(relay11PUMPMIDDLE, LOW); setColor("RED"); } else if ((dutyY <= -30) && (dutyX > -20) && (dutyX < 20)) //right { digitalWrite(relay7SOLELEFT, HIGH); digitalWrite(relay10PUMPLEFT, HIGH); digitalWrite(relay9SOLERIGHT, LOW); digitalWrite(relay12PUMPRIGHT, LOW); digitalWrite(relay8SOLEMIDDLE, LOW); digitalWrite(relay11PUMPMIDDLE, LOW); setColor("BLUE"); } else if ((dutyX >= 20) && (dutyY > -30) && (dutyY < 30)) //back {digitalWrite(relay8SOLEMIDDLE, LOW); digitalWrite(relay11PUMPMIDDLE, LOW); digitalWrite(relay7SOLELEFT, LOW); digitalWrite(relay10PUMPLEFT, LOW); digitalWrite(relay9SOLERIGHT, LOW); digitalWrite(relay12PUMPRIGHT, LOW); setColor("YELLOW"); } else if ((dutyX <= -20) && (dutyY > -30) && (dutyY < 30)) //foward { digitalWrite(relay8SOLEMIDDLE, HIGH); digitalWrite(relay11PUMPMIDDLE, HIGH); digitalWrite(relay7SOLELEFT, LOW); digitalWrite(relay10PUMPLEFT, LOW); digitalWrite(relay9SOLERIGHT, LOW); digitalWrite(relay12PUMPRIGHT, LOW); setColor("PURPLE"); } else if ((dutyY >= 30) && (dutyX >= 20)) // adelante + izquierda { } else if ((dutyY >= 30) && (dutyX <= -20)) // adelante + derecha { } else if ((dutyY <= -30) && (dutyX >= 20)) // atras + izquierda { } else if ((dutyY <= -30) && (dutyX <= -20)) // atras + derecha { } else { } } void setColor(String color) { if (color == "RED") { digitalWrite(R_LED_PIN, LOW); // High values -> lower brightness digitalWrite(G_LED_PIN, HIGH); digitalWrite(B_LED_PIN, HIGH); }else if (color == "GREEN") { digitalWrite(R_LED_PIN, HIGH); // High values -> lower brightness digitalWrite(G_LED_PIN, LOW); digitalWrite(B_LED_PIN, HIGH); }else if (color == "BLUE") { digitalWrite(R_LED_PIN, HIGH); // High values -> lower brightness digitalWrite(G_LED_PIN, HIGH); digitalWrite(B_LED_PIN, LOW); }else if (color == "PURPLE") { digitalWrite(R_LED_PIN, LOW); // High values -> lower brightness digitalWrite(G_LED_PIN, HIGH); digitalWrite(B_LED_PIN, LOW); }else if (color == "YELLOW") { digitalWrite(R_LED_PIN, LOW); // High values -> lower brightness digitalWrite(G_LED_PIN, LOW); digitalWrite(B_LED_PIN, HIGH); } }

Credits

blight3d28

Hi, I'm Computer Scientist, love robotics & programming.

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Gesture Controlled Soft Robot Tentacle

About the project

Project info

Items used in this project

Hardware components

Hand tools and fabrication machines

Story

Schematics, diagrams and documents

Sketch

CAD, enclosures and custom parts

Watch case

inner design_mold_tentace

Tentacle mold

Air pump/air valve cases

V2 tentacle mold

Tentacle base

Code

Transmitter

Receiver

Credits

blight3d28

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