Connecting to BRKTSTBCDP5004 sensor breakout board with Raspberry Pi

[T_Sher]

Hi all,

I would like to know if the BRKTSTBCDP5004 differential pressure sensor breakout board can be used without the FRDMSTBCDP5004 design and instead can be attached to a Raspberry Pi 3 using a MCP3008 ADC?

Any advice would be very much appreciated.

Thank you.

[TomasVaverka · Accepted solution]

Hi Tillman,

Yes, it should be very easy to interface the BRKTSTBCDP5004 breakout board to the Raspberry Pi 3 using a MCP3008 ADC.

The BRKTSTBCDP5004 breakout board has an analog output (J2-1 - AOUT_5V) which can be directly connected to the ADC input. Its output voltage is typ. from 1V when no pressure is applied to 5V when max. differential pressure of 4kPa is applied.

You can find the schematic of the BRKTSTBCDP5004 breakout board at: https://www.nxp.com/downloads/en/schematics/BRKTSTBCDP5004-SCH.pdf

Best regards,

Tomas

[T_Sher]

Hi Tomas, 

Thank you for the response. I have since connected the breakout board and ADC with the Raspberry Pi and am getting readings. However, I am a little confused by the output. 

I am getting the output by calling the 16-bit channel.value and channel.voltage of the ADC as per this tutorial. At no pressure difference between the ports I typically read the following:

Raw ADC Value: 23808
ADC Voltage: 1.20529

Is this a typical offset for this type of sensor? Can I use this 0.2V offset to use the following formula (V = 0.95P + 1.2) from the plot below to convert to kPa? Or would you recommend a different method? 

Thanks again for your help.

Kind regards,

Tillman

[TomasVaverka]

Hi Tilman,

Yes, as you can notice in the datasheet (Table 3), the offset can be anywhere between 0.75V and 1.25V.

The sensitivity is 1V/kPa, so I would recommend to use the following formula:

Vout = P + 1.2 => The max pressure the sensor will be able to measure is about 3.8 kPa.

Best regards,

Tomas