PR33-15 device not detected by the Pico W on the i2c bus

I connected the NCD PR33-15 to a Raspberry Pico W that is underneath the LCD.

The pico has an i2c logic voltage level of 3.3V.

I have tried changing wires and connecting a SI7021 in the same bus. The SI7021 is detected on the i2C bus but not the NCD PR33-15.

Any recommended steps I should take to troubleshoot?

Does the MCP3728 require a current loop in its channel to begin communication?

The MCP3728 is powered by 5V, so I think you need a voltage adapter for the Rpi Pico W to recognize the (5V) I2C device.

I have used SparkFun Logic Level Converter - Bi-Directional to convert 3.3V to 5V

The image of the (new) setup:

I have connected a SI7021 in parallel on the I2C bus to rule out connectivity issues.
I can detect the SI7021 on the same I2C bus but not the NCD PR33-15?

Am i missing anything?
Any troubleshooting steps?

Thank you in advance!

Try putting two pull-up resistors at 3.3V on the raspberry pico side, disconnect the SI7021 sensor and check if you can read the address of the NCD PR33-15. also check that your cables are in good condition.

I hope this can help you!

Attempt made. Still cannot detect the NCD PR33-15. :pensive:

I appreciate your efforts and guidance.

Could try your first connection, this one:

But with Pull-up enable:

And add an electrolytic 100uF capacitor between 5v and GND.

I hope this can help you.

The pico runs a 3.3V logic level.

I am scared that the pico might not be able to read a 5V i2c communication and worse might damage the pico.

I am moving to an arduino just to make sure that the NCD PR33-15 works.

I am planning to use this code: Arduino Code Git Repo

SCL → A5 (10K pull up to 5V or NCD onboard pull-up)
SDA → A4 (10K pull up to 5V or NCD onboard pull-up)
5V → 5V

If that works, I will come back to the pico.

Not an intensive arduino user, let me know if you know something that surely works with the PR33-15.


I hooked it to an arduino, and connected it directly to the PR33-15. I used the onboard pull-up resistors. I used the code provided in the link.
I get nothing from the ADC.

You could try this Arduino code that it runs the i2c scan and try to check if detect any i2c address.


Output Serial Monitor:

Same Outcome unfortunately. :pensive:


It’s very difficult for us to provide technical support on the i2c products. There are so many variables that can interfere with functionality. The only way we can provide support for connecting to a Pi is if you use our Pi I2C interface adapters:

These adapters handle voltage adaption on the SDA and SCL lines.