Smart_Car_Seat_v1 - This is the first version of the mbed program for…

Smart Car Seat GT Design Expo Spring 2017 » Code » Smart_Car_Seat_v1

Smart Car Seat GT Design Expo Spring 2017 / Mbed 2 deprecated Smart_Car_Seat_v1

This is the first version of the mbed program for the Smart Car Seat developed by the Smart Car Seat Team of GaTech Design Expo Spring 2017.

Dependencies: Adafruit_FONA FSR SDFileSystem mbed

Fork of Smart_Car_Seat_v1 by Jea Du Kim

Team Members

Bryan Bates – OBD/Bluetooth System
Robert Dunkin – Physical Wiring/Power
Jgenisius Harris – Cooling System
Jea Du Kim – Sensor System
Emily Pitts – Smartphone Application
Tyler Woei-A-Sack – GSM Communications

Advisor

Dr. Mick West

Overview

Car Seat Pic Car Seat Diagram

The purpose of this project was to design a child’s safety car seat with Internet of Things capabilities and a cooling system that activates in the case of an emergency. It is comprised of a network of sensors, a wireless notification system, and a cooling system.

How Does It Work

The Smart Car Seat is initially set up using a smartphone application where the user inputs their phone number. The number is saved to an SD card and is read by the GSM module when it sends the text messages. If the infrared thermometers read a critical temperature and the force sensitive resistors detect someone, the cooling system will turn on and a text message will be sent to the phone number on file.

Smart Car Seat Program

Import program Smart_Car_Seat_v1

This is the first version of the mbed program for the Smart Car Seat developed by the Smart Car Seat Team of GaTech Design Expo Spring 2017.

Components

/media/uploads/jd0205/overall_carseat_schematic.jpg

This project involves the usage of the mbed LPC1768.

400

Force Sensitive Resistors

250

This project uses 4 Square FSR Interlink 406, two placed on the seat and two placed on the back rest to detect if someone is sitting on the seat.

mbed	FSR	Voltage Divider
p20	FSR Bottom Left	10K
p19	FSR Upper Left	10K
p18	FSR Upper Right	10K
p17	FSR Bottom Right	10K

/media/uploads/jd0205/fsrschematic3.jpg

As they are still resistors, the orientation of the pins do not matter, as long as one end goes into VCC and the other leads to a voltage divider and an AnalogIn like shown in the diagram. With a 10K Ohm voltage divider, a raw analog value of 0.5 for each FSR should be enough to distiguish an object of the size of a small child on the sensor.

Any additional information can be found at the Force Sensitive Resistors page.

Import library
FSR - FSR Class Reference

Public Member Functions
	FSR (PinName Pin, float resistance)
	Create an FSR object.
float	readRaw ()
	Read the raw data.
float	readFSRResistance ()
	Read the resistance of the FSR .
float	readWeight ()
	Read the weight in N.

MLX90614 IR Thermometers

250

This project uses two MLX90614 IR Thermometer placed on the back of the headrest to measure the temperature of the child sitting on the seat and the ambient temperature.

mbed	FSR	Pullups	Pulldowns
gnd	VSS - gnd
Vout	VDD - 3.3V		0.1uF (to VSS)
p27	SCL - I2C Clock	10K
p28	SDA - I2C Data	10K

250

At around room temperature, the Thermometers should read approximately 22 C. When reading the temperature from the palm, the sensors should read approximately between 30 and 35 C.

With the MLX90614 and I2C, you can run up to 127 thermometers through the same SCL and SDA connection as long as they have different 7-bit addresses. The default I2C address for the MLX90614 is 0x5A, but it can be changed with this program.

Import program MLX90614 IR_Temp_Sensor (change address)

I have spent so much time looking into how to change the address of a MLX90614 sensor for use of multiple sensors, so I think it might be helpful to somebody.

Any additional information can be found at the MLX90614 I2C IR Thermometer page.

SD Card File System

250

This project uses the basic SD Card reader that works with the mbed to store all the contact information for the system.

mbed	MicroSD Breakout
p8 (DigitalOut)	CS
p5 (SPI MOSI)	DI
Vout	VCC
p7 (SPI SCLK)	SCK
GND	GND
p6 (SPI MISO)	DO
nc	CD

Careful

VCC is the 3.3V from Vout. Using the 5V will damage the SD card.

Information

The project uses a simple .txt file to store a 10-digit phone number. Before operations, check if the file is named correctly and in the correct directory based on your code.

Any additional information can be found at the SD Card File System page.

Import library SDFileSystem

SDFileSystem

GSM Module

250

This project used the FONA 808 MiniGSM provided from Adafruit to send messages to the contact information stored in the SD Card.

mbed	Adafruit FONA
nc	Bat
GND	GND
nc	SPKR+
nc	SPKR-
p12	Rst
nc	PS
GND	Key
p11	RI
p14 (Serial RX)	TX
p13 (Serial TX)	RX
nc	NS
Vout (3.3V)	Vio

Warning!

Adafruit Fona 800/808 will only work when there's an external battery connected with at least 3.4V. When the battery is at a low level, the MicroUSB charger should be plugged in with the battery. Be careful with low rated batteries as the USB will charge at 4.2V.

Both the 800 and the 808 uses the same protocols, so any additional documentations, information, and project libraries can be found at the Adafruit FONA 800 Project page.

Import library
FONA_Cellphone_Library - Adafruit_FONA Class Reference

Data Structures
class	EventListener
	Listener for FONA events. More...
Public Member Functions
	Adafruit_FONA (PinName tx, PinName rx, PinName rst, PinName ringIndicator)
	Create instance of the Adafruit_FONA .
bool	begin (int baudrate)
	Built-in Test to see if FONA is connected.
void	setEventListener ( EventListener *eventListener)
	Set the event listener for incoming calls.
int	readable (void)
	Check if FONA has anything in its output buffer.
bool	getADCVoltage (uint16_t *v)
	Get ADC voltage from external pin.
bool	getBattPercent (uint16_t *p)
	Get battery percentage level.
bool	getBattVoltage (uint16_t *v)
	Get battery voltage level.
bool	unlockSIM (char *pin)
	Unlock SIM if needed.
uint8_t	getSIMCCID (char *ccid)
	Get the SIM chip card interface device (CCID)
uint8_t	getNetworkStatus (void)
	Get the Network Status of FONA.
uint8_t	getRSSI (void)
	Get the RSSI of the network signal.
uint8_t	getIMEI (char *imei)
	Get the International Mobile Station Equipment Identity (IMEI)
bool	setAudio (uint8_t a)
	Set the Audio Output interface.
bool	setVolume (uint8_t i)
	Set the Audio Volume.
uint8_t	getVolume (void)
	Get the Audio Volume.
bool	tuneFMradio (uint16_t station)
	Tune the FM radio.
bool	FMradio (bool onoff, uint8_t a=FONA_HEADSETAUDIO)
	FM radio set output.
bool	setFMVolume (uint8_t i)
	Set the FM Radio Volume.
int8_t	getFMVolume ()
	Get the FM Volume.
int8_t	getFMSignalLevel (uint16_t station)
	Get the FM signal strength.
bool	setSMSInterrupt (uint8_t i)
	Set the SMS Interrupt.
uint8_t	getSMSInterrupt (void)
	Get SMS Interrupt Setting.
int8_t	getNumSMS (void)
	Set the SMS Interrupt.
bool	readSMS (uint8_t i, char smsbuff, uint16_t max, uint16_t readsize)
	Read SMS.
bool	sendSMS (char smsaddr, char smsmsg)
	Send SMS.
bool	deleteSMS (uint8_t i)
	Delete SMS.
bool	getSMSSender (uint8_t i, char *sender, int senderlen)
	Send SMS.
bool	enableNetworkTimeSync (bool onoff)
	Enable FONA to sync time with the cellular network.
bool	enableNTPTimeSync (bool onoff, const char *ntpserver=0)
	Enable FONA to sync time with the time server.
bool	getTime (char *buff, uint16_t maxlen)
	Retrieve the current time from the enabled server.
bool	setPWM (uint16_t period, uint8_t duty=50)
	Control the buzzer capability of the PWM out on the FONA.
bool	callPhone (char *phonenum)
	Call a phone.
bool	hangUp (void)
	Hang up a phone call.
bool	pickUp (void)
	Answer a phone call.
bool	callerIdNotification (bool enable)
	Enable/disable caller ID.
bool	incomingCallNumber (char *phonenum)
	Retrieve the incoming call number.

Bluetooth Module

250

This project uses the HC-05 Bluetooth Module to connect with an Android app to update or change contact information stored in the SD Card.

mbed	Bluetooth
p9 (TX)	RX
p10 (RX)	TX
GND	GND
Vout	VCC

The Bluetooth module simple acts as a wireless Serial connection, so there is no need for additional Libraries other than the Serial.

Any additional information about Serial connections can be found at the Serial page.

Import library mbed

No documentation found.

Cooling System

250 250

The Cooling System involves the use of a MOSFET Relay and a combination of 5V Fans, Peltier Plates, and Heatsinks to provide cold air when commanded to.

mbed	MOSFET Relay	Cooling System
gnd	JP2-2 - gnd
5V	JP2-1 - RAW
p16	JP2-3 - Control
	JP1-1	Device (Neg)
	JP1-2	Device (Pos)

Any additional information about Relays can be found here.

main.cpp@1:a33e55fecf16, 2017-05-03 (annotated)

Committer:: jd0205
Date:: Wed May 03 23:03:22 2017 +0000
Revision:: 1:a33e55fecf16
Parent:: 0:5a4b2c91de63

v1.1

Who changed what in which revision?

User	Revision	Line number	New contents of line
jd0205	0:5a4b2c91de63	1	#include "mbed.h"
jd0205	0:5a4b2c91de63	2	#include "FSR.h"
jd0205	0:5a4b2c91de63	3
jd0205	0:5a4b2c91de63	4	#include <ctype.h>
jd0205	0:5a4b2c91de63	5	#include <string>
jd0205	0:5a4b2c91de63	6
jd0205	0:5a4b2c91de63	7	#include "SDFileSystem.h"
jd0205	0:5a4b2c91de63	8	#include "Adafruit_FONA.h"
jd0205	0:5a4b2c91de63	9
jd0205	0:5a4b2c91de63	10	#define FONA_RST p12
jd0205	0:5a4b2c91de63	11	#define FONA_TX p13
jd0205	0:5a4b2c91de63	12	#define FONA_RX p14
jd0205	0:5a4b2c91de63	13	#define FONA_RI p11
jd0205	0:5a4b2c91de63	14
jd0205	0:5a4b2c91de63	15	Serial pcSerial(USBTX, USBRX);
jd0205	0:5a4b2c91de63	16
jd0205	0:5a4b2c91de63	17	DigitalOut led1(LED1); //Fona status - on(connecting), off(disconnecting)
jd0205	0:5a4b2c91de63	18	DigitalOut led2(LED2);
jd0205	0:5a4b2c91de63	19	DigitalOut led3(LED3); //Pressure status - on(child on seat), off(off seat)
jd0205	0:5a4b2c91de63	20	DigitalOut led4(LED4); //Temperature status - on(Too hot), off(not hot)
jd0205	0:5a4b2c91de63	21
jd0205	0:5a4b2c91de63	22	Adafruit_FONA fona(FONA_TX, FONA_RX, FONA_RST, FONA_RI); //GSM
jd0205	0:5a4b2c91de63	23
jd0205	0:5a4b2c91de63	24	SDFileSystem sd(p5, p6, p7, p8, "sd"); //SD card reader
jd0205	0:5a4b2c91de63	25
jd0205	0:5a4b2c91de63	26	DigitalOut CtrlRelay(p16); //Relay Controller
jd0205	0:5a4b2c91de63	27
jd0205	0:5a4b2c91de63	28	FSR bottomFSR1(p20, 10); // Pin 17-20 is used as the AnalogIn pin and a 10k resistor is used as a voltage divider for the FSR
jd0205	0:5a4b2c91de63	29	FSR topFSR1(p19, 10);
jd0205	0:5a4b2c91de63	30	FSR topFSR2(p18, 10);
jd0205	0:5a4b2c91de63	31	FSR bottomFSR2(p17, 10);
jd0205	0:5a4b2c91de63	32
jd0205	0:5a4b2c91de63	33	I2C i2c(p28, p27); //I2C commands
jd0205	0:5a4b2c91de63	34
jd0205	0:5a4b2c91de63	35	Serial bt(p9, p10); //Bluetooth module
jd0205	0:5a4b2c91de63	36
jd0205	0:5a4b2c91de63	37	float temp, avgTemp; //temperature in degrees C
jd0205	0:5a4b2c91de63	38	const int addr1 = 0xB4; //Default MLX90614 address - 0x5A
jd0205	0:5a4b2c91de63	39	const int addr2 = 0x08; //Changed another MLX90614 address to 0x04
jd0205	0:5a4b2c91de63	40	char data[3];
jd0205	0:5a4b2c91de63	41	bool danger;
jd0205	0:5a4b2c91de63	42	int onForce;
jd0205	0:5a4b2c91de63	43
jd0205	0:5a4b2c91de63	44	float temp1,temp2,temp3,temp4,avgF;
jd0205	0:5a4b2c91de63	45
jd0205	0:5a4b2c91de63	46	char pnum[22];
jd0205	0:5a4b2c91de63	47	char message[141]= "Emergency! Your child is still in the Smart Car Seat!";
jd0205	0:5a4b2c91de63	48	//Message to send to phone and contacts
jd0205	0:5a4b2c91de63	49
jd0205	0:5a4b2c91de63	50	class FonaEventListener : public Adafruit_FONA::EventListener {
jd0205	0:5a4b2c91de63	51	virtual void onRing() {
jd0205	0:5a4b2c91de63	52	led1 = 1;
jd0205	0:5a4b2c91de63	53	}
jd0205	0:5a4b2c91de63	54
jd0205	0:5a4b2c91de63	55	virtual void onNoCarrier() {
jd0205	0:5a4b2c91de63	56	led1 = 0;
jd0205	0:5a4b2c91de63	57	}
jd0205	0:5a4b2c91de63	58	};
jd0205	0:5a4b2c91de63	59	FonaEventListener fonaEventListener;
jd0205	0:5a4b2c91de63	60	//GSM Module initalization
jd0205	0:5a4b2c91de63	61
jd0205	0:5a4b2c91de63	62	bool onSeat(float fLevel); //Checks if there is a child on the seat
jd0205	0:5a4b2c91de63	63	float readTemp(int addr, char* cmd); //Reads the temperature through the I2/C
jd0205	0:5a4b2c91de63	64	void callback(void); //Changes the stored number on the SD card
jd0205	0:5a4b2c91de63	65
jd0205	0:5a4b2c91de63	66	int main() {
jd0205	0:5a4b2c91de63	67	pcSerial.baud(9600); //Set the serial baudrate to 9600
jd0205	0:5a4b2c91de63	68	wait(2); //Wait 2 secs to initialize and settle
jd0205	0:5a4b2c91de63	69	i2c.frequency(50000); //Set the I2C frequency to 50kHz for the MLX90614
jd0205	0:5a4b2c91de63	70	wait(2); //Wait another 2 secs for initalization
jd0205	0:5a4b2c91de63	71
jd0205	0:5a4b2c91de63	72
jd0205	0:5a4b2c91de63	73	char cmd1[1];
jd0205	0:5a4b2c91de63	74	char cmd2[1];
jd0205	0:5a4b2c91de63	75	cmd1[0] = 0x07; //Command to read object temperature
jd0205	0:5a4b2c91de63	76	cmd2[0] = 0x06; //Command to read ambient temperature
jd0205	0:5a4b2c91de63	77
jd0205	0:5a4b2c91de63	78
jd0205	0:5a4b2c91de63	79	pcSerial.printf("FONA basic test\r\n");
jd0205	0:5a4b2c91de63	80	pcSerial.printf("Initializing....(May take 3 seconds)\r\n");
jd0205	0:5a4b2c91de63	81	// See if the FONA is responding
jd0205	0:5a4b2c91de63	82	if (! fona.begin(9600)) {
jd0205	0:5a4b2c91de63	83	pcSerial.printf("Couldn't find FONA\r\n");
jd0205	0:5a4b2c91de63	84	while (1);
jd0205	0:5a4b2c91de63	85	}
jd0205	0:5a4b2c91de63	86	fona.setEventListener(&fonaEventListener);
jd0205	0:5a4b2c91de63	87	pcSerial.printf("FONA is OK\r\n");
jd0205	0:5a4b2c91de63	88
jd0205	0:5a4b2c91de63	89
jd0205	0:5a4b2c91de63	90	bt.attach(&callback); //Allows the app to change the phone number
jd0205	0:5a4b2c91de63	91
jd0205	0:5a4b2c91de63	92
jd0205	0:5a4b2c91de63	93	//Reads the stored phone number
jd0205	0:5a4b2c91de63	94	FILE *fpr = fopen("/sd/mydir/myphone.txt", "r");
jd0205	0:5a4b2c91de63	95	if(fpr == NULL) {
jd0205	0:5a4b2c91de63	96	error("Could not open file for read\n");
jd0205	0:5a4b2c91de63	97	}
jd0205	0:5a4b2c91de63	98	fscanf(fpr,"%s", pnum);
jd0205	0:5a4b2c91de63	99	pcSerial.printf("Phone Number: %s\n", pnum);
jd0205	0:5a4b2c91de63	100	fclose(fpr);
jd0205	0:5a4b2c91de63	101
jd0205	0:5a4b2c91de63	102
jd0205	0:5a4b2c91de63	103	danger = false;
jd0205	0:5a4b2c91de63	104
jd0205	0:5a4b2c91de63	105	while (1) {
jd0205	0:5a4b2c91de63	106	if (onSeat(0.2)) //Checks if child is on the seat
jd0205	0:5a4b2c91de63	107	// 0.2 is very low, 0.5 for moderate touch, 0.8 for heavy pressing
jd0205	0:5a4b2c91de63	108	{
jd0205	0:5a4b2c91de63	109	led3 = 1;
jd0205	0:5a4b2c91de63	110
jd0205	0:5a4b2c91de63	111	temp1 = readTemp(addr1, cmd1); //Read object temperature (C)
jd0205	0:5a4b2c91de63	112	temp2 = readTemp(addr2, cmd1);
jd0205	0:5a4b2c91de63	113	//temp3 = readTemp(addr1, cmd2); //Read ambient temperature (C)
jd0205	0:5a4b2c91de63	114	//temp4 = readTemp(addr2, cmd2);
jd0205	0:5a4b2c91de63	115
jd0205	0:5a4b2c91de63	116	avgTemp = (temp1+temp2)/2; //Average value
jd0205	0:5a4b2c91de63	117	//avgTemp = (temp3+temp4)/2;
jd0205	0:5a4b2c91de63	118	printf("%5.2f\r\n",avgTemp);
jd0205	0:5a4b2c91de63	119
jd0205	0:5a4b2c91de63	120	if ( avgTemp > 30) //If value exceed a "bad" temperature
jd0205	0:5a4b2c91de63	121	{
jd0205	0:5a4b2c91de63	122	led4 = 1;
jd0205	0:5a4b2c91de63	123	CtrlRelay = 1; //Turn on cooling system
jd0205	0:5a4b2c91de63	124	danger = true;
jd0205	0:5a4b2c91de63	125	} else if ( avgTemp < 25) //When it falls back down
jd0205	0:5a4b2c91de63	126	{
jd0205	0:5a4b2c91de63	127	led4 = 0;
jd0205	0:5a4b2c91de63	128	CtrlRelay = 0; //Turn off cooling system
jd0205	0:5a4b2c91de63	129	}
jd0205	0:5a4b2c91de63	130	if (danger) { //When child is in "danger"
jd0205	0:5a4b2c91de63	131	fona.sendSMS(pnum, message); //FONA will send message to the contact
jd0205	1:a33e55fecf16	132	wait(1); //Adjust wait time after sending a message
jd0205	0:5a4b2c91de63	133	}
jd0205	0:5a4b2c91de63	134	} else {
jd0205	0:5a4b2c91de63	135	led3 = 0;
jd0205	0:5a4b2c91de63	136	led4 = 0;
jd0205	0:5a4b2c91de63	137	CtrlRelay = 0; //When child is no longer on the seat
jd0205	0:5a4b2c91de63	138	danger = false; //The system resets
jd0205	0:5a4b2c91de63	139	}
jd0205	1:a33e55fecf16	140	wait(1); //Adjust wait time after reading
jd0205	0:5a4b2c91de63	141	}
jd0205	0:5a4b2c91de63	142	}
jd0205	0:5a4b2c91de63	143
jd0205	0:5a4b2c91de63	144	float readTemp(int addr, char* cmd) { //read the value from the MLX90614
jd0205	0:5a4b2c91de63	145	i2c.write(addr, cmd, 1, true);
jd0205	0:5a4b2c91de63	146	i2c.read(addr, data, 3); //Two bytes of data + 1 word of codes
jd0205	0:5a4b2c91de63	147
jd0205	0:5a4b2c91de63	148	temp = (((float)((data[1]<<8)\|data[0]))*0.02) - 273.15;
jd0205	0:5a4b2c91de63	149	return temp;
jd0205	0:5a4b2c91de63	150	}
jd0205	0:5a4b2c91de63	151
jd0205	0:5a4b2c91de63	152	bool onSeat(float fLevel) { //Detects child by activating enough pressure sensors
jd0205	0:5a4b2c91de63	153	onForce = 0;
jd0205	0:5a4b2c91de63	154	if (bottomFSR1.readRaw() > fLevel) {
jd0205	0:5a4b2c91de63	155	onForce += 1;
jd0205	0:5a4b2c91de63	156	}
jd0205	0:5a4b2c91de63	157	if (bottomFSR2.readRaw() > fLevel) {
jd0205	0:5a4b2c91de63	158	onForce += 1;
jd0205	0:5a4b2c91de63	159	}
jd0205	0:5a4b2c91de63	160	if (topFSR1.readRaw() > fLevel) {
jd0205	0:5a4b2c91de63	161	onForce += 1;
jd0205	0:5a4b2c91de63	162	}
jd0205	0:5a4b2c91de63	163	if (topFSR2.readRaw() > fLevel) {
jd0205	0:5a4b2c91de63	164	onForce += 1;
jd0205	0:5a4b2c91de63	165	}
jd0205	0:5a4b2c91de63	166	return onForce >= 2;
jd0205	0:5a4b2c91de63	167	}
jd0205	0:5a4b2c91de63	168
jd0205	0:5a4b2c91de63	169	void callback(void) { //Rewrites the phone number saved in the SD card
jd0205	0:5a4b2c91de63	170	bt.gets(pnum,11);
jd0205	0:5a4b2c91de63	171	pcSerial.printf("New number: %s\n", pnum);
jd0205	0:5a4b2c91de63	172
jd0205	0:5a4b2c91de63	173	FILE *fp = fopen("/sd/mydir/myphone.txt", "w");
jd0205	0:5a4b2c91de63	174	if(fp == NULL) {
jd0205	0:5a4b2c91de63	175	error("Could not open file for write\n");
jd0205	0:5a4b2c91de63	176	}
jd0205	0:5a4b2c91de63	177	fprintf(fp, "%s\n", pnum);
jd0205	0:5a4b2c91de63	178	fclose(fp);
jd0205	0:5a4b2c91de63	179	}

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	04 May 2017
Imports:	2
Forks:	0
Commits:	2
Dependents:	0
Dependencies:	4
Followers:	5