Motorola MPX4115A pressure sensor

[Texy]

Has anyone had experience of this device?

Although I don't know exactly my height above sea level, I estimate that it is around 200-400feet.

According to the datasheet, I should expect Vout to be around 4.03 volts with a 5volt supply,

but I,m getting 4.09 volts, which equates to -36 feet. This is reading directly from the device with a high

quality DVM. Also some days it reads slightly less and other days slight more, but never anywhere

near what I expect it to be. I can only assume that the atmospheric pressure also plays a part in its reading.

I read in the datasheet that temperature is compensated for (over a large range), but no mention of the

weather is mentioned.

What am I not taking into account?

(or does Motorola have a help forum).

TIA

Texy

 

[HappyHobit]

Hi Texy,

"Texy" <texy@nospam.btinternet.com> wrote in message
news:csmr6a$ifj$1@sparta.btinternet.com...

Has anyone had experience of this device?
Although I don't know exactly my height above sea level, I estimate that it
is around 200-400feet.
According to the datasheet, I should expect Vout to be around 4.03 volts
with a 5volt supply,
but I,m getting 4.09 volts, which equates to -36 feet. This is reading
directly from the device with a high
quality DVM.

With an allowable error of +/-1.5% ( +/- .075 volts) your error of .06 volts
seems reasonable.

Also some days it reads slightly less and other days slight more, but never
anywhere
near what I expect it to be. I can only assume that the atmospheric
pressure also plays a part in its reading.
I read in the datasheet that temperature is compensated for (over a large
range), but no mention of the
weather is mentioned.

You are measuring 'atmospheric pressure' so anything that affects it (warm
of cold air above your head) will affect it. What you have right now is a
barometer.

Jay