Phil V
Published © GPL3+

Freedom Chair

Wheelchair add-on allows quadriplegic individuals to have greater freedom with a puff-controlled robotic arm and various safety mechanisms.

AdvancedFull instructions provided5 hours319

Things used in this project

Hardware components

DRIVE wheel chair
×1
OWI Robotic Arm Edge
×1
LED (generic)
LED (generic)
×5
wire conduit
×1
Adafruit MPRLS ported pressure sensor breakout
×2
Grove - Round Force Sensor (FSR402)
Seeed Grove - Round Force Sensor (FSR402)
×2
Battery, 3.7 V
Battery, 3.7 V
×1
JS Series Switch
C&K Switches JS Series Switch
×1
Resistor 10k ohm
Resistor 10k ohm
×7
Adafruit TCA9548A I2C Multiplexer
×1
Boron
Particle Boron
×1
Adafruit Ultimate GPS FeatherWing
×1
Adafruit DC Motor + Stepper FeatherWing Add-on For All Feather Boards
×2
Adafruit Quad Side-By-Side FeatherWing Kit with Headers
×1
Galvanized Steel Two Hole Strap, 1-1/4" Pipe Size
×1
Machine Screw with Nut, 6-32-Inch x 1-Inch, 10-Pack
×1
metal clothes hanger
×1

Software apps and online services

SMS Messaging API
Twilio SMS Messaging API
Ubidots
Ubidots
Particle Build Web IDE
Particle Build Web IDE

Hand tools and fabrication machines

3D Printer (generic)
3D Printer (generic)
Multitool, Screwdriver
Multitool, Screwdriver

Story

Read more

Custom parts and enclosures

Force Sensitive Resistor case

Its an STL file which can be downloaded and put onto your 3D-printer application

Force Sensitive Resistor Cover

Its an STL file which can be downloaded and put onto your 3D-printer application

Spacer for Arm mount

This is was made specifically for the drive wheel chair, however it should not be too hard to edit to fit your wheel chair.

Schematics

Freedom Chair Fritzing Diagram

Fritzing image of the circuit powering the Freedom Chair

Code

Complete Code for Particle Boron - Freedom Chair

Arduino
#include <Debounce.h>


#include "lib1.h"

#include <Ubidots.h>

#include "Particle.h"
#include "AssetTrackerRK.h"
#include <Adafruit_MPRLS.h>
#include "TCA9548A-RK.h"
#include <Adafruit-MotorShield-V2.h>
 
#define RESET_PIN  -1  // set to any GPIO pin # to hard-reset on begin()
#define EOC_PIN    -1  // set to any GPIO pin to read end-of-conversion by pin
  
#ifndef UBIDOTS_TOKEN
#define UBIDOTS_TOKEN "****" // Put here your Ubidots TOKEN
#endif 

Ubidots ubidots(UBIDOTS_TOKEN, UBI_UDP);
  
  
SYSTEM_THREAD(ENABLED);

void displayInfo(); // forward declaration

const unsigned long PUBLISH_PERIOD = 120000;
const unsigned long SERIAL_PERIOD = 5000;

// GPS variables and parameters
AssetTracker t;
unsigned long lastSerial = 0;
unsigned long lastPublish = 0;
unsigned long startFix = 0;
bool gettingFix = false;
int seatAlert = 0;
boolean inSeat = true;

// reset seat alert button, currently assigned to D2
long currentResetDebounce, previousResetDebounce;
long debounceInterval = 75;
int currentResetButton, previousResetButton;
int resetButtonState = HIGH;

char lastLocation[128]; // used for out of seat check alert

double lastLat = 0;
double lastLon = 0;

// Seat check variables and parameters
int leftSeatSensor, rightSeatSensor;
long currentSeatCheck, previousSeatCheck;
const long seatCheckInterval = 1500;


// sip/puff control variables and parameters
Adafruit_MPRLS mpr = Adafruit_MPRLS(RESET_PIN, EOC_PIN);
TCA9548A mux0(Wire, 0);
long currentSelect, previousSelect;
const long selectInterval = 50;

int motorIndex;
const int maxIndex = 5;

int lights[] = {7, 4, 6, 5, 3, 8};

// Motor variables and parameters
Adafruit_MotorShield AFMS0 = Adafruit_MotorShield(); 
Adafruit_MotorShield AFMS1 = Adafruit_MotorShield(0x61); 

Adafruit_DCMotor *baseMotor     = AFMS0.getMotor(1);
Adafruit_DCMotor *shoulderMotor = AFMS0.getMotor(2);
Adafruit_DCMotor *elbowMotor    = AFMS0.getMotor(3);
Adafruit_DCMotor *wristMotor    = AFMS0.getMotor(4);
Adafruit_DCMotor *gripMotor     = AFMS1.getMotor(2);
Adafruit_DCMotor *lightMotor    = AFMS1.getMotor(1);


Debounce debouncer = Debounce();

long currentUbidots, previousUbidots;
long ubidotsUpdateInterval = 2500;

bool updateUbidots()
{
   
  char* str_lat = (char *) malloc(sizeof(char)* 10);
  char* str_lng = (char *) malloc(sizeof(char)* 10);
  sprintf(str_lat, "%f", lastLat);
  sprintf(str_lng, "%f", lastLon);
  char* context = (char *) malloc(sizeof(char) * 30);
    
  ubidots.addContext("lat",str_lat);
  ubidots.addContext("lng",str_lng);
  ubidots.getContext(context); 
  ubidots.add("position", 1.0, context); 
  
  ubidots.add("Left_Seat_Sensor", leftSeatSensor);  // Change for your variable name
  ubidots.add("Right_Seat_Sensor", rightSeatSensor);

  bool bufferSent = false;
  bufferSent = ubidots.send(); 
  
  free(str_lat);
  free(str_lng);
  free(context);
    
}

void setup()
{
	Serial.begin();
	// Turn on GPS module
	
	Particle.variable("seatAlert", seatAlert);
    Particle.variable("latitude", lastLat);
    Particle.variable("longitude", lastLon);
	
	
	t.gpsOn();

	// Run in threaded mode - this eliminates the need to read Serial1 from loop or updateGPS() and dramatically
	// lowers the risk of lost or corrupted GPS data caused by blocking loop for too long and overflowing the
	// 64-byte serial buffer.
	t.startThreadedMode();

    startFix = millis();
    gettingFix = true;

    // If using an external antenna, uncomment this line:
    // t.antennaExternal();
    
    mux0.begin();
	mux0.setChannel(1);
	
	Serial.println("MPRLS Simple Test");
    if (! mpr.begin()) 
    {
        Serial.println("Failed to communicate with MPRLS sensor, check wiring?");
    }
  
    Serial.println("Found MPRLS sensor");
    
    // motor indicator lights
    pinMode(D8, OUTPUT);
    pinMode(D7, OUTPUT);
    pinMode(D6, OUTPUT);
    pinMode(D5, OUTPUT);
    pinMode(D4, OUTPUT);
    pinMode(D3, OUTPUT);
    
    // out of seat reset button
    //pinMode(D2, INPUT);
    debouncer.attach(D2, INPUT_PULLUP);
    debouncer.interval(35);
    
    
    
    
    // seat pressure/force resistor sensors
    pinMode(A0, INPUT);
    pinMode(A1, INPUT);
    currentSeatCheck = millis();
    previousSeatCheck = currentSeatCheck;
    
    
    AFMS0.begin();
    AFMS1.begin();
    baseMotor->setSpeed(250);
    shoulderMotor->setSpeed(250);
    elbowMotor->setSpeed(250);
    wristMotor->setSpeed(250);
    gripMotor->setSpeed(250);
    lightMotor->setSpeed(250);
}

void loop()
{
	// In threaded mode, you must not call updateGPS() from loop - it's handled automatically
	// from a separate thread if you call t.startThreadedMode()
    // Serial.println("check");
    // Out of seat alert check:
    currentSeatCheck = millis();
    if ((currentSeatCheck - previousSeatCheck) > seatCheckInterval)
    {
            previousSeatCheck = currentSeatCheck;
            leftSeatSensor = analogRead(A0);
            rightSeatSensor = analogRead(A1);
            // Serial.print("Checking Seat: ");
            // Serial.print("LS: ");Serial.print(leftSeatSensor);
            // Serial.print(" RS: ");Serial.print(rightSeatSensor);
            // Serial.print(" SeatCheck(inSeat, seatALert) ");Serial.print("(");
            // Serial.print(inSeat);Serial.print(",");Serial.print(seatAlert);
            // Serial.println(")");
            
            if ( (leftSeatSensor > 1200) || (rightSeatSensor > 1200))
            {
        	    
        	    if (inSeat) 
        	    {
                    inSeat = false;
                    seatAlert = 1;
                    
                    String smsLat = String(lastLat);
                    String smsLon = String(lastLon);
                    String emerGPS = String("OUT OF SEAT @ LAT: " + smsLat + " and LON: " + smsLon  );
                    
        	        // Particle.publish("ALERT", "out", PRIVATE);
        	        // Particle.publish("twilio_sms", "emergency out of seat", PRIVATE);
        	        // Particle.publish("twilio_sms", emerGPS, PRIVATE);
        	       // Serial.print("OUT OF SEAT _ALERT_: ");Serial.println(seatAlert);
        	    }
            }
    }
    
    debouncer.update();

    if ((debouncer.read()==HIGH) && (inSeat == false))
    {
        
        inSeat = true;
    } else {
        // do nothing.
    }
    
    // Sip-Puff controller check
    currentSelect = millis();
    if ((currentSelect - previousSelect)>selectInterval)
    {
        previousSelect = currentSelect;
        
        mux0.setChannel(0);
        float pressure_hPa0 = mpr.readPressure();
        
        Serial.print("Pressure0 (hPa): "); Serial.println(pressure_hPa0);
        
        if ( pressure_hPa0 > 1050 ) 
        {
            motorIndex++;
            if (motorIndex > maxIndex) { motorIndex = 0;} // roll over
            // Serial.print("TO NEXT FUNCTION: "); Serial.println(motorIndex);
        } else if (pressure_hPa0 < 900) {
            motorIndex--;
            if (motorIndex < 0) { motorIndex = maxIndex; } // roll over
            // Serial.print("TO PREVIOUS FUNCTION: ");Serial.println(motorIndex);
        } else {
           //  Serial.print("NO SELECTION CONDITION: ");Serial.println("functionIndex");
        }
        
       // Serial.print("MOTOR INDEX: ");
        // Serial.print(motorIndex);
        
        // Serial.print(" DIGITAL INDEX: ");
        // Serial.println(lights[motorIndex]);
        
        for (int i=0; i<6; i++)
        {
            if (i == motorIndex)
            {
                digitalWrite(lights[i], true);
            } else {
                digitalWrite(lights[i], false);
            }
        }
        
        mux0.setChannel(1);
        float pressure_hPa1 = mpr.readPressure();
        int direction = 0;
         Serial.print("Pressure1 (hPa): "); Serial.println(pressure_hPa1);
        if (pressure_hPa1 > 1050) { direction = 1; }
        else if ( pressure_hPa1 < 900 ) { direction = -1; }
        else { direction = 0; }
        
        // Serial.print("DIRECTION: ");Serial.println(direction);
 
        switch (motorIndex)
        {
            case 0:
                if (direction > 0) { baseMotor->run(FORWARD); }
                else if (direction < 0) { baseMotor->run(BACKWARD); }
                else { baseMotor->run(RELEASE); }
                break;
            case 1:
                if (direction > 0) {shoulderMotor->run(FORWARD);}
                else if (direction < 0) {shoulderMotor->run(BACKWARD);}
                else { shoulderMotor->run(RELEASE); }
                break;
            case 2:
                if (direction > 0) {elbowMotor->run(FORWARD);}
                else if (direction < 0) {elbowMotor->run(BACKWARD);}
                else { elbowMotor->run(RELEASE); }
                break;
            case 3:
                if (direction > 0) {wristMotor->run(FORWARD);}
                else if (direction < 0) {wristMotor->run(BACKWARD);}
                else { wristMotor->run(RELEASE); }
                break;
            case 4:
                if (direction > 0) { gripMotor->run(FORWARD); }
                else if (direction < 0) { gripMotor->run(BACKWARD); }
                else { gripMotor->run(RELEASE); }
                break;
            case 5:
                if (direction > 0) { lightMotor->run(FORWARD);}
                else if (direction < 0) { lightMotor->run(BACKWARD);}
                else { lightMotor->run(RELEASE); }
                break;        
        }
    }    
    
    
    currentUbidots = millis();
    if ((currentUbidots-previousUbidots)>ubidotsUpdateInterval)
    {
        // Particle.publish
        previousUbidots = currentUbidots;
        if ( updateUbidots()) {
            
            // Serial.println("UBiDOTS UPDATED :)");
        } else {
            // Serial.println("UBIDOTS NOT UPDATE :(");
        }
        
    }
    
    
    
	displayInfo();
}

void displayInfo()
{
	if (millis() - lastSerial >= SERIAL_PERIOD) {
		lastSerial = millis();

		char buf[128];
		if (t.gpsFix()) {
			snprintf(buf, sizeof(buf), "location:%f,%f altitude:%f satellites:%d hdop:%d", t.readLatDeg(), t.readLonDeg(), t.getAltitude(), t.getSatellites(), t.getTinyGPSPlus()->getHDOP().value());
			// snprintf(lastLocation, sizeof(lastLocation), "location:%f,%f altitude:%f satellites:%d hdop:%d", t.readLatDeg(), t.readLonDeg(), t.getAltitude(), t.getSatellites(), t.getTinyGPSPlus()->getHDOP().value());
			snprintf(lastLocation, sizeof(lastLocation), "{\"position\": {\"value\":1, \"context\":{\"lat\": \"%f\", \"lng\": \"%f\"}}}", t.readLatDeg(), t.readLonDeg());
			lastLat = t.readLatDeg();
			lastLon = t.readLonDeg();
			
			if (gettingFix) {
				gettingFix = false;
				unsigned long elapsed = millis() - startFix;
				Serial.printlnf("%lu milliseconds to get GPS fix", elapsed);
			}
		}
		else {
			snprintf(buf, sizeof(buf), "no location satellites:%d", t.getSatellites());
			if (!gettingFix) {
				gettingFix = true;
				startFix = millis();
			}
		}
		Serial.println(buf);

		if (Particle.connected()) {
			if (millis() - lastPublish >= PUBLISH_PERIOD) {
				lastPublish = millis();
				Particle.publish("gps", buf, PRIVATE);
			}
		}
	}

}

Credits

Phil V

Phil V

2 projects • 12 followers
hi

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