Analog Airspeed to Pixhawk?

Hello,
Is there a way to connect the older, analog airspeed sensor to the Pixhawk?
Any help appreciated,
Steven

Hi Steven,

I haven’t done it, but am almost certain people are. Have a look at this and see if it helps:

plane.ardupilot.com/wiki/airspeed-3/

Hope that helps…

Any confirmation on this? I just spoke to a friend who said he spoke to 3DR tech support and they said that the Pixhawk requires the new digital airspeed sensor. The old analog sensors do not work with the Pixhawk. That’s terrible news since I have 4 planes I want to swap to Pixhawk with analog sensors already installed and I don’t want to spend an additional $55 per plane. Perhaps that is 3DRs business strategy?
Hopefully it’s just a firmware thing that will be fixed in the next release.

Somebody misunderstood something.
The Digital Airspeed sensor is only supported on the Pixhawk, but the analog sensor works on both APM and Pixhawk

Thank you for the clarification. Perhaps my friend has a faulty airspeed sensor. I’ll see if he have the name of the support rep who told him that so he can be corrected.

[quote=“JoshW”]Hi Steven,

I haven’t done it, but am almost certain people are. Have a look at this and see if it helps:

plane.ardupilot.com/wiki/airspeed-3/

Hope that helps…[/quote]

Thanks. That’s very helpful. It’s not totally clear which physical pin to select but with some investigation, I’m confident I will find the correct analog pin “11”.
Stevn

[quote=“iskess”]Any confirmation on this? I just spoke to a friend who said he spoke to 3DR tech support and they said that the Pixhawk requires the new digital airspeed sensor. The old analog sensors do not work with the Pixhawk. That’s terrible news since I have 4 planes I want to swap to Pixhawk with analog sensors already installed and I don’t want to spend an additional $55 per plane. Perhaps that is 3DRs business strategy?
Hopefully it’s just a firmware thing that will be fixed in the next release.[/quote]

Take a look at this plane.ardupilot.com/wiki/common- … -overview/. From the O&M and the airspeed instructions posted above, it is most probably ADC 6.6 that has to be connected in order to enable analog airspeed sensor readings. My educated guess is that the signal pin (2) is pin “11”. From my reading, the digital airspeed sensor offers more accuracy and compensation than the analog but like you said, $$$. Let us know if you try it. More than one smoke signal is not useful. :slight_smile:

I can’t remember the name of the tech rep from 3DR, but they looked up my order and said that it looked like I “mistakenly ordered the wrong pitot system with the pixhawk”, “the analog will not work with Pixhawk, only 2.x”, and that they would give me credit towards the correct digital set after I returned the analog. Before contacting 3DR, I tried connecting to both the 6.6 analog input and re-writing my params to Pin 15, and many other combinations! But nothing. I will try again tomorrow before trading it in for the digital, maybe I overlooked something…

In this documentation, plane.ardupilot.com/wiki/airspeed-3/, there is only pin 11 and pin 65 mentioned wrt airspeed for the Pixhawk and PX4.

But look in the Parameter descriptions:
Airspeed pin (ARSPD_PIN)
Note: This parameter is for advanced users

“…Set to 11 on PX4 for the analog airspeed port. Set to 15 on the Pixhawk for the analog airspeed port. Set to 65 on the PX4 or Pixhawk for an EagleTree or MEAS I2C airspeed sensor.”

So it should be 15 according to that.

Somewhere, I have seen a physical pin number decoder ring for Pixhawk. I can’t remember where but I’ll keep looking.

Ok. I found the info that identifies virtual pins. I’m going to permanently save it for future reference. FWIW it does indeed look like it’s pin 15 and the ADC 6.6V.

Ok, don’t know why I couldn’t get it to work the first time, maybe a loose DF13 connector, at any rate, I finally got it… the analog airspeed sensor does in fact work on the Pixhawk. Connect to ADC 6.6V, and set your ARSPD_PIN param to 15. Sorry for the drama.

No drama. Actually you brought to light two issues that 3DR must address:

  1. There is misinformation coming from 3DR tech support regarding the use of analog AS sensors on the Pixhawk.

  2. There is an error on the wiki airspeed page which does not identify the correct pin to use for analog airspeed sensors on the Pixhawk.

Thanks for pointing out the error in the wiki
I’ll get that corrected right away

Fixed.

Thanks guys. I love open source!

Open source is great, as long as everyone is open and helpful…