Airspeed sensor location?

Hi, i’m building a Cularis with a Black cube.
I’m going to place the Pitot tube 0.5m from the wing root in order to get it clear of the prop wash.
From your experience, what would give the best results, short silicone tubes between the sensor and the Pitot w/ long I2C wires or vice versa ?
I heard once that I2C protocol was meant originally for short PCB trails and not long wires…

Thanks, Guy.

Yes, generally more than 20cm of an I2C line is a problem. I have seen up to 50cm of silicone lines work just fine for airspeed sensors, as long as you don’t let them rattle too much.

Do you have need for more length than that?

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As mentioned by George, keep the wires short and make the tubes longer.

Rattling tubes would not hurt. It’s just ugly and increase the chance of failures.
Make sure you don’t pinch or squeeze the lines.

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Up to 1 meter shielded cables are worth a try, otherwise CAN bus.


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I’ve tried that with shielded twisted pairs, but no luck.
You can have 100% success with an I2C range extender chip, though. It’s a bit of a hassle though, for small builds.

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well, after taking into consideration the connectivity of the 1.3m long wing, I’ve ordered silicon tubing + interconnecting stainless tubes so the airspeed sensor would be in the body, next to the Cube.
I guess it’s easier to connect silicon tubing rather then I2C connectors…

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