Pitot airspeed and i2c ms4525do

Comments

• JonnyMac Posts: 9,371

  2020-03-23 17:33 edited 2020-03-23 17:34

  There doesn't seem to be a lot to reading values from the sensor -- except the required information seems to be spread across more than one document. The basics go like this:
  

  pub read_pitot
  
    i2c.start
    i2c.write($51)                                                ' read; other ids are $6D and $8D
    i2c.read(bridge.byte[1], i2c#ACK)
    i2c.read(bridge.byte[0], i2c#ACK) 
    i2c.read(temp.byte[1],   i2c#ACK) 
    i2c.read(temp.byte[0],   i2c#NAK)
    i2c.stop
  
    if (bridge & $C000)                                           ' check status bits, should be %00
      return false
  
    temp >>= 5                                                    ' fix lsb of temp  
  
      
    ' do bridge and temp calculations here
  
  
    return true
  

  In this suggestion, bridge and temp are global variables (words or longs). I'll leave the raw readings to useful values calculations to you.
• Ltech Posts: 385

  2020-03-23 20:23

  Whow, I didn't get one now.
  Just inform if somebody have user experience
  
  I go order one for testing
  
  Thank you Jon
• JonnyMac Posts: 9,371

  2020-03-23 20:35

  You're welcome. Keep in mind that I don't have one either, I just translated the data sheet to Spin. Hope it helps you get going with the sensor.
• Duane Degn Posts: 10,588

  2020-03-23 20:55 edited 2020-03-23 20:57

  Just invcase you haven't seen these, here's a sensor with an a pitot tube.
  
  I haven't used mine with the Propeller yet but I wouldn't think translating the open source C code to Spin shouldn't be too hard.

  

  

  Pitot200323a.PNG

  877 x 825 - 629K

  Pitot200323a.PNG 629.1K
• Ltech Posts: 385

  2020-03-24 07:43

  Duan, that was the one I looking for.
  
  There are two type of them, one with I2C(PX4), the other analogue (AMP cheap one).
  I go for the I2C, just put in my basket.
  
  Daniel