Between a rock and a hard place, again!

There’s been no progress on GPS routing in the last few days.

For RPi B3 performance reasons, I’m limited to down-facing video resolution of 320 x 320 pixels @ 10fps.  That rules out flying on the back lawn; only the gravel drive in sunshine* will do.  On the plus side, there’s a lot less clutter and more space on the drive once my wife’s gone to work in the morning.  On the downside, any negative flight result results in broken props.



I’ve only recently swapped from the T-motor CF to T-Motors white beechwood props, based on price, looks and sturdiness.  And this week, I’ve found out that the lovely white beechwoods are out of production.  It turns out I’d bought the UK’s stock last month, and, as a result, I’ve bought Germany’s (perhaps the EU’s) leftover stock this week.  As a result, these white props are in safe storage for show-and-tell at the Cotswold Raspberry Jam only; for testing, I’ve found these XOAR 12×4 beechwood props that are nearly identical, except they come in beechwood brown unsurprisingly.

These new props, combined with improved code changes have been tested, and as a result, GitHub has been updated.

Time now to finally get on with GPS routing, weather permitting – the forecast says rain for a week 🙁

*I am strongly considering adding down-facing bright LED lighting to Hermione so that flying conditions are not so significantly limited by weather conditions.

Hermione in wonderland.

Took her outside this morning, and the safety test without LiPo consistently threw I²C errors as yesterday.  I brought her straight indoors, still powered up, both her and my piPad and ran the same test; she worked perfectly. Curiouser and curiouser.

P.S. Shortly after writing the above, I had a eureka moment in the shower: I remembered reading LiPos don’t work well in the cold, and even the Mavic instructions suggest letting it run for a while before take off to let the battery chemistry warm out.  Next test then is to wrap both LiPos (batter bank and the main power) in bubble wrap, boot her up indoors, and then take her outside to fly.  I’ll report back here anon.

P.P.S. It worked!!!!! I wrapped both LiPos in some neoprene foam (normally used for scuba suits), set everything up and running the code and therefore the GLL and PWM to keep the LiPos warm indoors. After a couple of minutes, I lugged everything outside, and she did two flights without a glitch. Roll on spring / summer!

The only way is up, baby, for you and me now…

only trouble is, the lovely English summer has definitely gone now, and the renowned drizzly English Autumn has taken hold.

I still need to sort out fast safe, autonomous take-off by the drone, and there seems to be little advice out there since everyone has an RC which they hold up to full power, and then release to hover once it’s in the right place.  I could do that in the code, but it feels a bit clunky; I’d rather use the vertical acceleration / speed PIDs, and that’s what I’ve been tinkering with in the padded cell test environment, but the results of the limited testing showed either very slow takeoff resulting in yaw, or pogo-stick / trampoline takeoff which made me giggle but were also unacceptable in reality.  The net result of both was a crash due to the drone reaching the end of its tether.

So it’s outside I must go for untethered take-off landing testing.  Hence there may be some delay in any exciting updates as once more the weather has final say.

On the plus side, all this rain is softening up the concrete like soil in the garden, meaning it’s much better for the drone’s inevitable violent crashes!