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Bar02 pressure sensor and Tsys01 sensor

Hello there,

I’m using the Bar02 pressure sensor and Celsius Fast response sensor for a school project and am able to run both sensors independently. However when i connect both of them to the rpi both of there addresses disappear. By disconnecting them their addresses reappear so i’m wondering if there is an issue with the way I wired the sensors to the rpi.


Are you using i2c-detect to check for devices connected ?
Try to run each one individually with i2c-detect to debug.

Also, Raspberry I2C is 3.3V and you using the 5V input of the I2C Level Converter:

Try to use the 3.3V power supply pin of the raspberry and the I2C pins in the 3.3V part of the board.

  1. i2c-detect has some issues sometimes. Try also i2c-dump
  2. You may use 5v or 3.3v to power the sensors, but only 3.3v for the sda/scl communication lines
  3. i2c busses are sensitive to long wires, you should make the length of wire from the computer to the sensor as short as possible
  4. These senors/i2c are very sensitive to loose connections, if you need to use jumpers, make sure your jumper connections are really tight, minimize the jumper connections, and use high quality jumpers and breadboards. You will get the best results if you can solder the connections.
  5. The Raspberry pi uses 3.3v on the sda/scl lines, so you may remove the level converters in order to reduce the number of connections and wire length in your setup.