Communication between Arduino uno and BME280 with the converter SC18IM700

Hello Guys i have a problem with my XBee and Arduino uno. At first i want to show my setting.

The First XBee is configuared as Coordinator, pan id=2 and Broadcastmode, api mode
The wiring from Arduino and XBee S2C looks like:
RX pin from Arduino to TX pin XBee S2C
TX pin from Arduino to RX pin XBee S2C

The Second XBee S2C looks looks like:
RX pin XBee S2C to TX SC18IM700 (datasheet:
TX pin XBee S2C to RX SC18IM700
Configuarad as Router, same pan id, JV on, api mode

And from SC18IM700 to BME280: (datasheet: )
SCL SC18IM700 to SCK BME280
SDA SC18IM700 to SDA BME280

Why i need here a SC18IM700? Because the BME280 support only I2C or SPI so the SC18IM700 working here as a converter from I2C to Uart.

So my problem is if i am writing a simple code for my arduino to receive any datas, i get nothing. Whats wrong with my settings?

void setup() { Serial.begin(9600); }

void loop() {
if (Serial.available() > 0) {
int my =;

Best regards

Have you got the BME280 working when it's directly connected to the Arduino?

Personally, I'd use a small Arduino such as a Teensy or Pro Mini as my UART-I2C converter. Then I can plug in to that unit and see what it gets from each side and what it send out in response.

The concepts of I2C don't really translate directly into Serial concepts. I2C requires you to address an individual slave and the slave knows when you stop talking to it. Serial doesn't have addresses and it doesn't have stops.