Can only find i2c client or sensor, but not both

Projects Networking, Protocols, and Devices
1

Hey there,

I have the following system setup:
*10x of those pressure sensors (https://www.first-sensor.com/cms/upload/datasheets/DS_Standard-SSI_E_11671.pdf)
*1x Arduino Mega 2560
*1x Adafruit Feather NRF52480 Express (Adafruit Feather nRF52840 Express : ID 4062 : $24.95 : Adafruit Industries, Unique & fun DIY electronics and kits)
*2x 4.7kOhm resistors on the V5+ to SDA/SCL

My Goal is to read the air pressure from the sensors using the Mega and send them to the Adafruit NRF Module for BLE communication.

The Mega is the I2C-Master in the system, the NRF52 is the client.

I am using the I2C-Scanner example to verify that my devices are there. When I connect all sensors and the Module, the scanner only finds the NRF Module. If I remove it, I can see all the pressure sensors with their correct addresses.

Its my first bigger project using I2C, so maybe someone could have an idea where the problem could be. Thanks!

2

Which are the operating voltages of your I2C devices?

3

The Mega with 5V and the NRF52 is normally a 3.3V device. I have it powered with 5V at the USB pin.

The sensors get 5V from the same bus.

4

I can't check that because I don't have your same hardware and I never had to do with multiple I2C devices, but I was wondering if maybe is an I2C baudrate problem. Try lowering to 100 kHz and see what happens.

5

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