Hi,

The Humidity sensor SEN0438 is not transmitting any data to microcontroller Rx pin. The sensor connection is like this

red - +12V White - B of RS485 to TTL module

Black - Gnd Yellow - A of RS485 to TTL module

RS485 to TTL module connection

RO - RX and DI toTX RE and DE ns joined and set to a GPIO pin

The Code is here

RE and DE pin high;
USART_Transmit(0x01);
USART_Transmit(0x03);
USART_Transmit(0x00);
USART_Transmit(0x00);
USART_Transmit(0x00);
USART_Transmit(0x02);
USART_Transmit(0xC4);
USART_Transmit(0x0B);
_delay_ms(1);

RE and DE pin high;

in =USART_Receive();
in =USART_Receive();
in =USART_Receive();
in =USART_Receive();
in =USART_Receive();
in =USART_Receive();
in =USART_Receive();
in =USART_Receive();

No data is received .