Open Source Flipper Zero, Thread, Matter, and Zigbee on ESP32, Arduino go Zephyr, and more!

0:00:00 / -

Watch now on YouTube Watch now

Flex Controlled Air Powered Gripper

Made by blight3d28 / 3D Printing / Robotics / Sensors / Wearables

About the project

A silicone air powered gripper controlled with a flex sensor glove.

Project info

Difficulty: Moderate

Platforms: Adafruit, Arduino, Seeed Studio

Estimated time: 6 hours

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

Items used in this project

Hardware components

	Seeed Studio Grove - 2-Channel SPDT Relay I used 7 individual relays.	x 3
	Adafruit nOOds- Flexible LED Filament	x 1
	coin cell holder	x 1
	Arduino Nano 33 BLE Sense	x 2
	Long flex sensor	x 1
	Ecoflex 00-30	x 1
	Adafruit Air tube	x 1
	Adafruit Air valve	x 3
	Adafruit Air pump	x 3

View all

Hand tools and fabrication machines

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

Story

My project is a silicone gripper controlled with a flex sensor connected to my hand. When I close my hand the arduino nano 33 ble sense connected to the flex sensor sends a message to another nano 33 ble sense, the 2nd nano is connected to 7 relays. Each relay is connected to an air pump/valve (3 air pumps & 3 air valves), the final relay controls the nOOds green LED.

The silicone "fingers" are made of EcoFlex 00-30. I casted them using two 3D-printed molds, a top & bottom, which later is connected together using some eco-flex (also inserted an air tube in-between the two parts with a little bit of ecoflex to make sure it sticks).

Schematics, diagrams and documents

Transmitter _schematic

CAD, enclosures and custom parts

Base & top

Feed the air tubes through the holes & super glue the 3 fingers to each side. Super glue the top on the base.

Go to download

Glove_TPU

Glove made 3d printed out of tpu. Super glue flex sensor & electronics.

Go to download

Finger silicone molds

This makes the top & bottom of a silicone finger which you connect together with some silicone. The circular designs goes on the outside, the linear design goes on the inside.

Go to download

Code

Transmitter_BLE_Flex

The transmitter code, arduino nano 33 BE sense with a flex sensor sends msg via BLE to another arduino.

#include <ArduinoBLE.h> const int R_LED_PIN = 22; const int G_LED_PIN = 23; const int B_LED_PIN = 24; int voltageThreshold = 250; void setup() { Serial.begin(9600); // initialize the BLE hardware BLE.begin(); Serial.println("BLE Central - LED control"); // start scanning for peripherals BLE.scanForUuid("19b10000-e8f2-537e-4f6c-d104768a1214"); } void loop() { // check if a peripheral has been discovered BLEDevice peripheral = BLE.available(); 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(); if (peripheral.localName() != "LED") { return; } // stop scanning BLE.stopScan(); controlLed(peripheral); // peripheral disconnected, start scanning again BLE.scanForUuid("19b10000-e8f2-537e-4f6c-d104768a1214"); } } void controlLed(BLEDevice peripheral) { Serial.println("Connecting ..."); if (peripheral.connect()) { Serial.println("Connected"); } 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; } // retrieve the LED characteristic BLECharacteristic ledCharacteristic = peripheral.characteristic("19b10001-e8f2-537e-4f6c-d104768a1214"); if (!ledCharacteristic) { Serial.println("Peripheral does not have LED characteristic!"); peripheral.disconnect(); return; } else if (!ledCharacteristic.canWrite()) { Serial.println("Peripheral does not have a writable LED characteristic!"); peripheral.disconnect(); return; } while (peripheral.connected()) { int currentVoltage = analogRead(A0); // store the incoming voltage Serial.println(currentVoltage); if (currentVoltage < 200 ) { setColor("GREEN"); ledCharacteristic.writeValue((byte)0x01); } if (currentVoltage > voltageThreshold) { Serial.println("button released"); setColor("RED"); ledCharacteristic.writeValue((byte)0x00); } } Serial.println("Peripheral disconnected"); } 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_BLE_Flex

Receiver code, controls the relays connected to the 3 air pumps/3 air valves plus the nOOds LED.

#include <ArduinoBLE.h> BLEService ledService("19B10000-E8F2-537E-4F6C-D104768A1214"); // BLE LED Service // BLE LED Switch Characteristic - custom 128-bit UUID, read and writable by central BLEByteCharacteristic switchCharacteristic("19B10001-E8F2-537E-4F6C-D104768A1214", BLERead | BLEWrite); int relay7SOLELEFT = 7; int relay10PUMPLEFT = 10; int relay8SOLEMIDDLE = 8; int relay11PUMPMIDDLE = 11; int relay9SOLERIGHT = 9; int relay12PUMPRIGHT = 12; int relay5LED = 5; void setup() { Serial.begin(9600); pinMode(relay7SOLELEFT, OUTPUT); pinMode(relay10PUMPLEFT, OUTPUT); pinMode(relay8SOLEMIDDLE, OUTPUT); pinMode(relay11PUMPMIDDLE, OUTPUT); pinMode(relay9SOLERIGHT, OUTPUT); pinMode(relay12PUMPRIGHT, OUTPUT); pinMode(relay5LED, OUTPUT); // begin initialization if (!BLE.begin()) { Serial.println("starting BLE failed!"); while (1); } // set advertised local name and service UUID: BLE.setLocalName("LED"); BLE.setAdvertisedService(ledService); // add the characteristic to the service ledService.addCharacteristic(switchCharacteristic); // add service BLE.addService(ledService); // set the initial value for the characeristic: switchCharacteristic.writeValue(0); // start advertising BLE.advertise(); Serial.println("BLE LED Peripheral"); } 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, // use the value to control the LED: if (switchCharacteristic.written()) { if (switchCharacteristic.value()) { // any value other than 0 digitalWrite(relay8SOLEMIDDLE, HIGH); digitalWrite(relay11PUMPMIDDLE, HIGH); digitalWrite(relay7SOLELEFT, HIGH); digitalWrite(relay10PUMPLEFT, HIGH); digitalWrite(relay9SOLERIGHT, HIGH); digitalWrite(relay12PUMPRIGHT, HIGH); digitalWrite(relay5LED, HIGH); Serial.println("ON"); } else { // a 0 value digitalWrite(relay8SOLEMIDDLE, LOW); digitalWrite(relay11PUMPMIDDLE, LOW); digitalWrite(relay7SOLELEFT, LOW); digitalWrite(relay10PUMPLEFT, LOW); digitalWrite(relay9SOLERIGHT, LOW); digitalWrite(relay12PUMPRIGHT, LOW); digitalWrite(relay5LED, LOW); Serial.println("OFF"); } } } } }

Credits

blight3d28

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

Shop

Project Hub

Video

Blog

Shop home

3D printing

Single Board Computers

Development kits

Sensors

Internet of things

Robotics

Accessories

Product of the Week

Electromaker Educator

The Electromaker Show

The Electromaker Podcast

Flex Controlled Air Powered Gripper

About the project

Project info