Design a PIC $16F887$ based intelligent wrist band which measures the temperature and the SPO$2$ level $($blood oxygen level$)$ of a patient. The intellgent band is connected to a PC via the serial port and they communicate via the UART in asynchronous mode.

Body temperature of the patient is measured using an LM$35(10$ mV$/$degC$)$ connected to the AN$0$ pin. Assume that a reference voltage of $0\mathrm{.}5V$ is used in the ADC module of the microcontroller.

It is assumed that the SPO$2$ sensor module produces an analog output which is proportional to the SPO$2$ value such that the maximum output voltage of the module is $0\mathrm{.}5V$ when the SPO$2$ value is $100\%.$ The output of the SPO$2$ sensor module is connected to the AN$1$ input

PIC sends the values of the temperature, heart rate and SPO$2$ values to the PC via the USART serial port in the asynchronous serial communication mode, at a baud rate of $9600$ bits$/$s$.$

If the temperature of the patient is greater than $40$degC or the SPO$2$ value is less than $80\%,$ an SOS message is sent to the PC via the USART module and also an alarm is generated via a buzzer which is connected to the RD$0$ pin via a BC$237$ transistor.

a$)$ Draw the circuit diagram of the system by using the component models given in the Appendix. Indicate the connections and the components clearly

b$)$ Write a MicroC program to perform the above functions. Write your comments for each instruction, to explain its function and parameters clearly.

unsigned int temp, spo$2$;

char temp$\_$str$[8],$ spo$2\_$str$[8]$;

void main $0$

$\{$

ANSEL $=003$;

ANSELH $=000$;

UART$1\_$init$(9600)$;

while$(1)$

$\{$

temp $=$ ADC ${?}_R$ead$(0)$;

temp $=($long$)$ temp$100/1023$;

$//$ ALARM

if$($spo $2<mn\; id="EditorElement\_4469460">8</mn><mn\; id="EditorElement\_4469461">0</mn><mi\; id="EditorElement\_4469463">|</mi><mi\; id="EditorElement\_4469465">|</mi>$ temp $>40)$

$\{$

RDO$\_$bit $=1$;

delay$\_$ms $(500)$;

RD$0\_$bit $=0$;

$\}$

else RDO$\_$bit $=0$;

Int ToStr$($temp$,$ temp$\_$str$)$;

IntToStr$($spo$2,$ spo$2\_$str$)$;

UART$1\_$Write$\_$Text$("$ Temperature : $")$;

UART$1\_$Write$\_$Text$($temp$\_$str$)$;

UART$1\_$Write$\_$Text$("|$r$")$;

UART$1\_$Write$\_$Text$("$ Oxygen Level $(\%)$: $")$;

UART$1\_$Write$\_$Text$($spo$2\_$str$)$;

UART$1\_$Write$\_$Text$("(r^{\text{'}\text{'}})$;

delay$\_$ms $(1000)$; $\}\}$