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Topic: MPX4115A (Read 2292 times) previous topic - next topic

Things

Jun 26, 2010, 01:49 pm Last Edit: Jun 26, 2010, 03:36 pm by Things Reason: 1
Hi, I am trying to have an Arduino read the pressure in hectopascals (hPa) from a MPX4115A pressure sensor. The datasheet has a formula saying: Vout = Vs*(.009*P-.095)+/- Error

EDIT: OK, I now have the sensor reading in hPa :)
Code: [Select]
  P = (analogValue/1023.0 + 0.095) / 0.009;
  P2 = P * 10;


So, I guess now:

Also, since this is atmospheric pressure, is there any way to make the sensor more sensitive to a certain pressure range? I only need to measure between like 950 and 1040hPa, which is about a .6V voltage range on the sensors output, but using it like this is wasting ADC steps. SO if I can somehow get that .6V range to "stretch" between 0 and 1V, I can use the ATMega's internal 1V reference, for much better sensitivity between that range. Just not sure on how to do that, though :(

Cheers,
Dan

mrmeval

#1
Jun 27, 2010, 02:09 am Last Edit: Jun 27, 2010, 02:10 am by mrmeval Reason: 1
You can use an op-amp to extend the range.

First you use a voltage follower then a scaler.

http://www.electrotap.com/blog/503

You can try this separately and add the voltage follower buffer if you need it.
http://www.electrotap.com/blog/495

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