Saturday, July 31, 2021

HuVVer-AVI testing

I just got a HuVVer-AVI from a friend at Oshkosh (event recap to follow; this is just a quick technical note). It seems like a dandy little instrument platform that could be super useful. It is ESP32 based, and has no graphics acceleration or anti-aliasing of any sort. But it seems rather capable for what it is.

I messed with the code, and eventually got myself this very simple static demo of an "Airball" like display painting to the screen:

The loop() time for each paint iteration was 74 milliseconds. It is possible that the many arcs were taking lots of time to paint. By contrast, the following, which is one of the standard screens but with the colors flipped because I was messing with it:

takes 63 milliseconds to paint.

Currently, Airball operates at a 20fps update rate with time to spare, including saving and painting the last N raw "ball" images in fading color. It is clear to me that the HuVVer-AVI cannot maintain that kind of "instant feedback" feeling. It is an instrument, not a "virtual windsock" that flutters instantly with every little twitch.

But of course: is that important? It is to some people, and not to others. Is it important to our project? How does that compare to the fact that the HuVVer-AVI is very small, and is ready to use, made by someone else? I honestly don't know.

Monday, July 12, 2021

Wired probe mockup

In preparation for Oshkosh, I've been making some prototypes / mockups to discuss with people. The latest is a mockup of a wired probe -- using aluminum tubing (since we don't need WiFi to the probe). Here are a few photos. It's pretty amazingly lightweight, but I'm not going to weigh it till I get some .035 wall aluminum for the boom.

Tuesday, July 6, 2021

More mount design thoughts

The latest version of the adjustable strut mount seems to work fine but it has a tendency to be a bit wobbly and have some "hysteresis" in its alignment. First, here are some photos:

Now the hysteresis. Note in this video how the rear does not quite return to the exact same position when disturbed. This may be rectified partly by making the front part more rigid, but probably not quite. Now I'm thinking about solutions involving two items that "hug" the strut at 2 locations, with the variable structure in between them. Stay tuned.

One other thought is of course to just "give up" and add a hinge right behind the probe. I've been resisting this because it just re-iterates the problem of creating a reliable and stiff hinge, and it is not quite as easy to "boresight". But maybe this would indeed be the best....