Priscilla Cheng
Published

CapTouch Steering Wheel Touch Interface

Add a touch interface to the steering wheel of any car to control music on your phone!

AdvancedFull instructions provided2,109
CapTouch Steering Wheel Touch Interface

Things used in this project

Hardware components

Nordic nRF51-DK mbed board
×1
BeagleBone Black
BeagleBoard.org BeagleBone Black
×1
AD5932 Wave Generating IC
×1
LT1360 Op-Amp
×2

Story

Read more

Schematics

System Diagram

Code

Classifier run on Beaglebone

Python
import warnings
warnings.filterwarnings("ignore", category=RuntimeWarning) 
import numpy as np
import matplotlib.pyplot as plt
from sklearn import svm
import Adafruit_BBIO.UART as UART
import Adafruit_BBIO.GPIO as GPIO
import serial 
import time
import threading
from threading import Thread, current_thread

#setup UART connection
print "setup"
UART.setup("UART1")
ser1 = serial.Serial(port = "/dev/ttyO1", baudrate=9600)

dtr = "P9_23"
touch_ready = "P9_21"
send_again = "P9_22"
result0 = "P9_13"
result1 = "P9_11"

#setup
GPIO.setup(dtr, GPIO.OUT)				
GPIO.setup(touch_ready, GPIO.OUT)		
GPIO.setup(send_again, GPIO.OUT)		
GPIO.setup(result0, GPIO.OUT)
GPIO.setup(result1, GPIO.OUT)
#initialize
GPIO.output(touch_ready, GPIO.LOW)
GPIO.output(send_again, GPIO.LOW)
GPIO.output(result0, GPIO.LOW)
GPIO.output(result1, GPIO.LOW)

data = []
clf = svm.SVC(kernel = 'linear', C=1.0)


def isFloat(string):
    try:
        float(string)
        return True
    except ValueError:
        return False

def train_data():
	global clf
	
	#read in and parse our CSVs for training data
	train_data_notouch = open("notouch.csv", 'r')				#0
	train_data_onefinger = open("onehand_onetouch.csv", 'r')  				#1
	train_data_twotouch = open("onehand_twotouch.csv", 'r') 				#2
	train_data_fullgrip = open("onehand_fullgrip.csv", 'r') 				#3
	train_data_twohands = open("twohands.csv", 'r') 				#4

	train_data_notouch = list(train_data_notouch)
	train_data_onefinger = list(train_data_onefinger)
	train_data_twotouch = list(train_data_twotouch)
	train_data_fullgrip = list(train_data_fullgrip)
	train_data_twohands = list(train_data_twohands)

	for i,line in enumerate(train_data_notouch):
		train_data_notouch[i] = train_data_notouch[i].rstrip('\n').split(',')
		train_data_notouch[i] = train_data_notouch[i][0:70]

	for i,line in enumerate(train_data_onefinger):
		train_data_onefinger[i] = train_data_onefinger[i].rstrip('\n').split(',')
		train_data_onefinger[i] = train_data_onefinger[i][0:70]
	
	for i,line in enumerate(train_data_twotouch):
		train_data_twotouch[i] = train_data_twotouch[i].rstrip('\n').split(',')
		train_data_twotouch[i] = train_data_twotouch[i][0:70]

	for i,line in enumerate(train_data_fullgrip):
		train_data_fullgrip[i] = train_data_fullgrip[i].rstrip('\n').split(',')	
		train_data_fullgrip[i] = train_data_fullgrip[i][0:70]
	
	for i,line in enumerate(train_data_twohands):
		train_data_twohands[i] = train_data_twohands[i].rstrip('\n').split(',')	
		train_data_twohands[i] = train_data_twohands[i][0:70]
	
	
	#np_train_data_notouch = np.array(train_data_notouch)
	#np_train_data_notouch = np_train_data_notouch.astype(float)
	#mins_water = np.min(np_train_data_notouch)
	#print mins_water

	training_input = []
	training_output = []
	#train our classifier
	for k in range(1,4):
		for i in range(0,3):
			training_input.append(train_data_notouch[i])
			training_output.append(0)
		for i in range(0,3):
			training_input.append(train_data_onefinger[i])
			training_output.append(1)
		for i in range(0,3):
			training_input.append(train_data_twotouch[i])
			training_output.append(2)
		for i in range(0,3):
			training_input.append(train_data_fullgrip[i])
			training_output.append(3)
		for i in range(0,3):
			training_input.append(train_data_twohands[i])
			training_output.append(4)
		
	#fit the data
	X = training_input
	y = training_output
	clf.fit(X,y)
	print "training score:", clf.score(X,y)

def read_data():
	global data,  ser1, ready_for_classifier
	
	ser1.close()
	ser1.open()

	data_array = [];

	#read in data from mbed
	if ser1.isOpen():
		print 'serial open'
		count = 0
		while ser1.readable():
			
			GPIO.output(dtr, GPIO.HIGH)
			GPIO.output(dtr, GPIO.LOW)
			GPIO.output(send_again, GPIO.HIGH) #tell mbed to send
			#print 'before read'
			read_value = ser1.readline()
			#print 'after read'
			read_value = read_value.strip('\n')
			
			if read_value=="end":
				print "read a buffer"
				count = 0
				if data_array[0]!="start":
					print data_array[0], "discarded"
					data_array = []
					continue
				else:
					data_array.pop(0);
					data = data_array
					data_array = []
					#print "data received: ", data
					break
					
			else:
				data_array.append(read_value)
				count = count+1
								
	#ser1.close()				#should we keep serial opened or closed?

def run_classifier():
	global data, ser1, ready_for_classifier
	data_float = map(float, data)
	#print "floats to run classifier on: ", data		#print the data if it is new
	result = clf.predict(data_float) 
	print "position: ", result
	
	if result==0:
		print "no hands"
	elif result==1:
		print "one finger touch"
	elif result==2:
		print "two finger touch"
	elif result==3:
		print "full hand grip"
	elif result==4:
		print "two hands on steering wheel"
	else:
		print "n/a"
		
	
	GPIO.output(touch_ready, GPIO.HIGH)	#tell mbed interrupt that classification is done
	"""
	if data_float[0] > 0.5:
		result = 2
	if data_float[0] <= 0.5:
		result = 1
	"""
	ser1.write(chr(result))
				
		
			
	

if __name__ == '__main__':	
	
	train_data()
	time.sleep(1)
	
	while(1):
		read_data()
		run_classifier()
		GPIO.output(touch_ready, GPIO.LOW)
		GPIO.output(send_again, GPIO.LOW)	
		"""
		while 1:
			GPIO.output(touch_ready, GPIO.HIGH)
			print "high"
			GPIO.output(touch_ready, GPIO.LOW)
			print "low"
			time.sleep(3)
		"""

Data collection and BLE interface

C/C++
#include "mbed.h"
#include "ble/BLE.h"
#include "CaptouchService.h"
#include "Serial.h"
#include "BufferedSerial.h"

#define BTON 1
//#define BTEST 2

InterruptIn button1(BUTTON1);
InterruptIn button2(BUTTON2);
InterruptIn button3(BUTTON3);
InterruptIn button4(BUTTON4);

DigitalOut led1(LED1);
DigitalOut led2(LED2);
DigitalOut led3(LED3);
DigitalOut led4(LED4);
AnalogIn input(A0); //P0.01

DigitalOut trigger(P0_12);
DigitalOut test_out(P0_13);
InterruptIn touch_ready_interrupt(P0_14);
InterruptIn send_now_interrupt(P0_15);

Timer t;
static uint8_t touchState = 0;

#if defined(BTON)
const static char     DEVICE_NAME[] = "captouch";
static const uint16_t uuid16_list[] = {CaptouchService::CAPTOUCH_SERVICE_UUID};
static CaptouchService *captouchServicePtr;
#endif

char end_buffer[4] = "end";
char buffer[10];
char start_buffer[6] = "start";
int touch_ready = 0;
int send_now = 0;
int eventIncoming = 0;

Serial pc(USBTX, USBRX);
BufferedSerial beaglebone(P0_9, P0_11);
char touchStateChar = 'a';

#if defined(BTEST)
void button1RiseCallback(void)
{
    led1 = !led1;
    test_out = 0;
}

void button2RiseCallback(void)
{
    led2 = !led2;
    test_out = 1;
}

void button3RiseCallback(void)
{
    led3 = !led3;
    test_out = 0;
}

#else
void button1RiseCallback(void)
{
    test_out = 0;
}

void button2RiseCallback(void)
{
    led2 = !led2;
    test_out = 1;
}

void button3RiseCallback(void)
{
    led1 = !led1;
    test_out = 0;
}
#endif


#if defined (BTON)
void disconnectionCallback(const Gap::DisconnectionCallbackParams_t *params)
{
    BLE::Instance().gap().startAdvertising();
}

void onBleInitError(BLE &ble, ble_error_t error)
{
    printf("Error initializing BLE\n\r");
}

void bleInitComplete(BLE::InitializationCompleteCallbackContext *params)
{
    BLE&        ble   = params->ble;
    ble_error_t error = params->error;

    if (error != BLE_ERROR_NONE) {
        /* In case of error, forward the error handling to onBleInitError */
        onBleInitError(ble, error);
        return;
    }

    /* Ensure that it is the default instance of BLE */
    if(ble.getInstanceID() != BLE::DEFAULT_INSTANCE) {
        return;
    }

    ble.gap().onDisconnection(disconnectionCallback);

    /* Setup primary service */
    captouchServicePtr = new CaptouchService(ble, 0x00);

    /* setup advertising */
    ble.gap().accumulateAdvertisingPayload(GapAdvertisingData::BREDR_NOT_SUPPORTED | GapAdvertisingData::LE_GENERAL_DISCOVERABLE);
    ble.gap().accumulateAdvertisingPayload(GapAdvertisingData::COMPLETE_LIST_16BIT_SERVICE_IDS, (uint8_t *)uuid16_list, sizeof(uuid16_list));
    ble.gap().accumulateAdvertisingPayload(GapAdvertisingData::COMPLETE_LOCAL_NAME, (uint8_t *)DEVICE_NAME, sizeof(DEVICE_NAME));
    ble.gap().setAdvertisingType(GapAdvertisingParams::ADV_CONNECTABLE_UNDIRECTED);
    ble.gap().setAdvertisingInterval(1000); /* 1000ms. */
    ble.gap().startAdvertising();

}
#endif


void touchReadyState() {
    touch_ready = 1;
}

void sendNow() {
    send_now = 1;
}

int main(void)
{
    uint8_t old_touchState = 0x00;
    beaglebone.baud(9600);
    float data_float, elapsed, start_time, end_time;
    int i;
    led1 = 1;
    led2 = 1;
    led3 = 1;
    led4 = 1;
    test_out = 1;
    
    #if defined (BTON)
    BLE &ble = BLE::Instance();
    ble.init(bleInitComplete);
    #endif
    
    t.start();
    
    #if defined (BTON)
    while (ble.hasInitialized()  == false) { }
    #endif
    
    touch_ready_interrupt.rise(&touchReadyState);
    send_now_interrupt.rise(&sendNow);
    button1.rise(&button1RiseCallback);
    button2.rise(&button2RiseCallback);
    button3.rise(&button3RiseCallback);
    
    
    while(1) {
        i = 0;
        //t.start();
        //start_time = t.read();
        if (send_now==1) {
            //__disable_irq();
            while (i < 70) {
                if (i==0) {
                    beaglebone.puts(start_buffer);
                }
                if (i==10) {
                    trigger = 1;                //give a couple samples leeway before pulsing trigger
                }
                data_float = input.read();
                sprintf(buffer, "%f", data_float);
                beaglebone.puts(buffer);
                memset(buffer, 0, sizeof(buffer));
                i++;
                trigger = 0;
            }
        
            //end_time = t.read();
            //beaglebone.puts(timebuf);
            beaglebone.puts(end_buffer);
            //__enable_irq();
            send_now = 0;
            //sprintf(timebuf, "%f", end_time - start_time);
            //printf("%f", end_time - start_time);
        }
        if (touch_ready==1) //touch_ready is updated by the interrupt when 
        {
            if (beaglebone.readable()) {    
                touchStateChar = beaglebone.getc();
            }
            touch_ready = 0;
            
            #if defined (BTON)
            if (ble.getGapState().connected) {
                touchState = int(touchStateChar) - 256; //convert to uint8
                if (old_touchState != touchState) {
                    captouchServicePtr->updateTouchState(touchState);
                    old_touchState = touchState;
                    led4 = !led4;
                }
            }
            #endif
        }
        led3 = !led3;   
        //wait(0.3);
        
    }

}

Credits

Priscilla Cheng

Priscilla Cheng

2 projects • 3 followers
Thanks to Ivan Poupyrev, Munehiko Sato, Chris Harrison.

Comments

Related channels and tags
  • BeagleBoard.org