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Precision Sensor Board

Precision Sensor Board

I recently designed a board that incorporates digital pressure, temperature, and dewpoint sensors I’ve called the PTU board. I deal with weather balloon tracking systems and the information sent back from the radiosondes is usually called PTU data (Pressure, Temperature, and Humidity).

I’ve written 2 new Arduino libraries for the pressure and temp and reused an existing library for the humidity sensor. You’ll notice in the readings that all 3 have temperature sensors embedded in them. One is a little higher than the temperature sensor itself and one is a little lower. Guess if the temp sensor failed you could average the other two for a good reading :). Current output using Arduino based boards is as follows:

Absolute Pressure : 987.42 mBar
Relative Pressure : 1021.95 mBar
Pressure: 30.18 inHg
 
P_Sensor Temp: 21.69°C
P_Sensor Temp: 71.04°F
 
*************************************
 
T_Sensor Temp: 21.45°C
T_Sensor Temp: 70.62°F
 
*************************************
 
Humidity: 38.07%
U_Sensor Temp: 21.20°C
U_Sensor Temp: 70.16°F
 
Dew Point: 6.58°C
Dew Point: 43.84°F
 
Heat Index: 69.17°F
 
*****2-Minute Averages*****
Avg_P: 30.18 inHg
Avg_T: 70.60°F
Avg_U: 37.84%
Avg_DewPt: 43.67°F
 
My only issue now is to figure out how to properly house one of these to make it a viable sensor to place outdoors. You can find electronics enclosures all over the place, but finding “probe” enclosures that you could place a breathable filter on the end seems to be very difficult. 
 
Any feedback or questions is welcome!
 
Sensor Info:

4 Comments

  1. Profile photo of Heather Brooks

    Great post! Thanks for sharing it and for featuring it in the Gadget Showcase.

  2. Profile photo of neilh

    Hi Rick
    Great to see, and I like the specs on the devices you’ve chosen.
    Have you a reference or a plan on where you might release the libraries – software and hardware design.
    Mechanical enclosures are a challange, and unfortunately, if you are doing a real-world design for a specific environment (weather balloon?) its one of the starting points. The other starting point is power budget. One way of talking about this is how the device is used – the lifecycle of data collection.

    • Profile photo of Rick Vogel

      neihl,
      This device wouldn’t be used in a weather balloon type environment, that’s just one of the areas I deal in most with NWS. I have a side business where I currently only sell NOAA Weather Radio / SAME Decoder modules for arduino and raspberry pi usage and wanted to expand my device offerings. I won’t post the site, cause that’s not really my intent to joining this group. I really just enjoy sharing ideas and experiences when it comes to using arduino with real world sensor devices. If someone is interested they can ask.

      I see this more as a datalogger sensor addition, but would really like a way to build it into a probe that would fit into an aspirated or unaspirated type enclosure. I’m sure I could just make it available as is for those who might want to integrate how they see fit.

      libraries would be set up on GitHub. I need to start making that the standard since that is where everything is going these days. My radio files were just posted on my website for download, but those most likely need to be moved as well.

      • Profile photo of Rick Vogel

        By the way, as far as enclosures go. I’ve had great luck, even when it comes to customization using TEKO, PacTec and Polycase.

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