A suitable pressure sensor for e-cigarette application for sensing air flow

[shai_b]

Hello Team,

Could you please suggest a suiatlabe pressure sensor for sensing the airflow in the E-CIG application?

the minimum requirements as follow:

• Pressure range – the main issue is to indicate the human inhale, which could be used in the e-cigarette
• Temp range 0-40 deg. C 
• Supply voltage 3.3-5VDC

Looking forward to your recommendations, Thanks a lot.

Best regards,

Shai

[reyes · Accepted solution]

Hi,

I don’t have experience with the application of e-cigarettes, but I’m assuming for this application…

1. The pressure range is small around 2 to 4 kPa (please correct me if I’m wrong),
2. Since it is for human inhale you need to measure negative pressure,
3. And I would personally use a device that can handle both negative and positive pressure mainly for protection of the device (in case someone exhale in the e-cigarrate).

Based on these points and your requirements, I would like to recommend you the MPXV7002DP: https://www.nxp.com/docs/en/data-sheet/MPXV7002.pdf

Regards,

Jose

[shai_b]

Dear @reyes, 

Thank you a lot for your inputs, Can you please suggest a suitable pressure sensor with a digital output?

Could I offer him the MPL3115A2 as an option for a pressure sensor with a digital output? Thanks in advance.

Kind regards,

Shai

[reyes]

Hi,

Correct, MPL3115A2 is a digital ouput solution.

And other digital output options are:

FXPQ3115: https://www.nxp.com/docs/en/data-sheet/FXPQ3115BV.pdf

FXPS7115: https://www.nxp.com/docs/en/data-sheet/FXPS7115D4.pdf

Regards,

Jose

[shai_b]

@reyes,

I've noticed that there is no digital pressure sensor that can measure negative pressure.

Since as far as I know the physics of breathing, the inhales pressure is around –4 mm Hg to -10 mm Hg (negative) which is around 0.5 – 1.5 kPa (negative) but the MPL3115 starts from +20 kPa (up to 110 kPa).

Could you please suggest the right implementation technic to detect human inhale with MPL3115?

Thanks in advance
Kind regards,
Shai

[reyes]

Hi Shai,

Unfortunately, it would not be possible to measure pressure below +20kPa using the MPL3115A2

For this case, I would return back to my initial recommendation, the MPXV7002 which can measure negative and positive pressure in the range from -2kPa to +2kPa.

This is an analog output sensor, so you would need to use an external ADC to convert the analog signal to a digital signal.

MPXV7002 datasheet: https://www.nxp.com/docs/en/data-sheet/MPXV7002.pdf

Regards,

Jose

[shai_b]

Got it, Thanks.

KR,

Shai