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May 18, 2019, 09:05 AM
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Discussion

airspeed sensor, pololu, Teensy 3.2 I2C daisy chain


I'm adding airspeed to my homegrown (working) Teensy flight recorder. This thing has worked fine for a couple of years recording to a microSD, time, gps position, mag heading, gps-altitude, barometric height, horizontal accuracy, vertical accuracy, and roll, pitch and yaw.

System employed a Pololu IMU and a real-time clock daisy chained I2C to the teensy powered from a separate 5 volt PS.

I'm adding SBUS fields to each record for control inputs and throttle setting. So the last thing I needed to complete data was airspeed.

I have an EagleTree Airspeed Micro-Sensor V3. After the blundering reported on another post, I have it configured for I2C use.

I have some questions.

Does the Airspeed V3 require more current than can be produced by a Teensy 5 volt port?

Could I power it off the plane's 5 volt line?

Will adding the two pull-ups to the I2C bus that was working ok before cause a problem? I haven't checked but assumed that maybe there were pull-ups on one of the other devices?

Has anyone else done this, and of so, am I missing anything?
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May 18, 2019, 09:47 AM
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Maybe a better question is:

Does the sensor need to be powered by the separate "stand-alone" cable while connected by I2C to my controller?
May 19, 2019, 10:45 PM
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Nuts,
Eagletree's I2C address for the v3 airspeed sensor was listed as 0xEA. After spending days trying to figure out why my code wouldn't work, I tried Nick Gammon's wonderful scanner which showed 0x75 as the address when connected to my Nano.

Using 0x75, and adding a 5 millisecond delay to the read cycle, I'm in business.

Is it possible that no-one reading here is doing anything like this anymore?
Last edited by jferguson; May 20, 2019 at 06:40 AM.


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