Task: Modify the program to turn on an LED connected to pin $13$ if the temperature exceeds a certain threshold $($e$.$g$.,\backslash (25^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash )).$

Procedure:

$1.$ Set up the LED using direct register access as done in Part $1.$

$2.$ Use a function to turn on the LED if the temperature exceeds the threshold.

Code Example:

$```$

#include $"$RHTwh$"$

#define DHTPIN $7$

#define DHTTYPE DHT$11$

##efine TEMP$\_$THRESHOLD $25\mathrm{.}0//$ Temperature threshold in Celsius

DHT dht$\{($DHTPIN$,$ DHTTYPE$)$;

$//$ Function to initialige the DHT sensor and pin $13$

$```$

$```$

ghtweggix$()$; $//$ Initialize the DHT sensor

DDRB $|=\{($ DDB$5)$; $//3$et pin $13$ as output $($direct register access$)$

$\}$

$//$ Function to read temperature and humidity

$```$

$```$

$*$ humidity $=$ dhtwreadHuridita$(?$;

$```$

$```$

$\}$

$//$ Function to control LED based on temperature

void GQRtr&lJER$\{$float temperature$)\{$

if $\{$temperature $>$ TEMP$\_$THRESHOLD$\backslash \backslash \backslash$

PORTB $|=\{1\backslash$ll PORTB$5\backslash$; $//$ Turn LED on $($direct register access$)$

$//($the easy way would be digitadJxiter$\{13,$ HIGH$)$;$)$

$\}$ else $\{$

PORTB &$=\backslash$cong$(1$ PORTB$5)$; $//$ Turn LED off

$\}$

$\}$

void setupl$)\{$

Seximb$\_**$gin$(9600)$: $//3$tart serial communication

$```$

$```$

$\}$

void loop$()$ &

float temp, hum;

$```$

$```$

$//$ Check if any reads failed and exit the loop early

$```$

$```$

return:

$\}$

$```$

$```$

S$9$RtratJER$\{$templ: $//$ Control the LED based on the temperature

delay$[2000)$; $//$ Delay for $2$ seconds

$\}$

$```$

Discussion:

$-$ Explore how combining sensor data and register manipulation in a modular program provides flexibility.

$-$ You can experiment with different thresholds and modify the LED behavior.