Tuesday, 27 June 2017

FPV Hoops (Video)

I've had a wee project going on over the last little while, to create some neato FPV hoops for the micro quads to fly through.

The initial prototype for these came from an article on how to control RGB LED strip (non-indexable) from an Arduino. Not only did I have the RGB strip laying around after an impulse AliExpress purchase, but I also somehow, miraculously, managed to salvage the MOSFETs I needed from an old computer power supply that I had stuffed under my desk.

A bit of fiddling, some code copying, a few tweaks, and voila! I had a working led strip, and a few minutes later I'd made a circle out of some garden hose and I had a hoop to fly through.

I played with the idea for a while, pricing things up on AliExpress to see how I could make more, and in the end settled for some pre-build LED strip controllers, plus some other bits and bobs, and managed to price these hoops up at a fairly reasonable rate.

So I purchased the parts for 10 of them.

Mark and I spend an evening putting together the first one - ironing out the assembly process and figuring out what works and what doesn't. We managed to get one done, so along with the prototype had two hoops.

We had grand aspirations of assembling many, but we didn't get much further than that - with the Mobius Mini recording in the corner of the room we went off to see what we had created, and it was absolute madness.

The hoops are awesome - in a dark room where they are the only source of light they provide a decent amount of illumination, or if turned down they provide a good night challenge (the stock cameras on the QX95 is really good in low light conditions - grainy, but good). We weren't so sure about the insane flashing modes - when one of the rings was set to insane-speed-flashing it was actually causing problems with our VTX. Not sure if this was to do with the frequency of the switching in the LED controller or something else, but interesting to note at least.

We had too much fun.

All in the name of product research of course. We could have stopped any time.


A few days later we now have 9 of them in various sizes between 80cm and 60cm, and they are the best thing ever. One rainy day we did a little indoor flying, and have plans to get these out in the Playground as soon as the weather starts behaving itself.

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Monday, 26 June 2017

Taranis, V8JT and V8R4 receivers

My shiny new FrSky Taranis X9D Plus SE Carbon arrived the other day, and since then it's been a mad scramble to learn how it works and get it attached to everything.
Previously I was running an old analogue JR PCM9X-II Transmitter and was using an FrSky V8JT transmitter pack to get 2.4G goodness. This has worked well, but it was time for an upgrade. I temporarily upgraded to the DJT transmitter pack so I could bind to my current-favourites, the Eachine QX95 Micro Quad, but immediately found that it wasn't backwards compatible with my old V8R4 receivers. (note: we're not talking about the V8R4-II here, that's a different receiver).

I worked around this, and when picking out my new Taranis I was aware that it also wasn't backwards-compatible with the original series receivers - they use a protocol that is no longer supported by any of the currently produced tech.

However, the original V8JT transmitter pack does talk to those old receivers, and it happens to be a supported module of the Taranis. This means if you have a V8JT and any old V8R4 receivers, or those of a similar vintage, laying around you can get them working with your fancy new TX rather than going out and replacing old RXs that probably work perfectly well.

One of mine survived a crash in the ocean. Bulletproof. They don't make 'em like that any more sonny.

Being able to use the V8JT with the Taranis is actually hinted to in the Taranis quick-start guide, but there isn't any additional info on how to set it up, and the internet wasn't much help.

I'm sure there are a lot of reasons to just buy new receivers and replace the old ones. You can pick up an FrSky compatible receiver with classic PWM servo outputs for as little as $12(NZD) on Banggood, so it probably isn't worth running out and grabbing a V8JT just to do this, but if you happen to have one laying around...

How to get it all working

Here's what you need to do to get your V8JT working with your Taranis. If you have a different receiver the process is probably exactly the same because that is just between the transmitter module and the receiver.
  • Stick the V8JT module in the back of the Taranis
  • Go to your model settings, disable the internal TX and enable the external TX
  • Set the mode to PPM
  • These are the default settings and they work for me. If your defaults are different perhaps try those, but these ones do work for me:
  • Bind the V8JT to the receiver normally, which is something like this:
    • Turn on the Taranis while holding the bind button on the receiver. Lights will flash.
    • Turn on the receiver while holding the bind button. Lights will flash.
    • Done. Restart both devices and test the connection.
Hopefully this helps, and you'll be able to dust off some old receivers, save a few $$, and fly some things that probably shouldn't have ever flown again.
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Wednesday, 21 June 2017

Turnigy Bonsai Mobius Mini and TX02 Mount

The thing I love about having a 3D printer is really the rapid prototyping. I've deliberately avoided posting a whole bunch of stuff about printing, but it is great for smashing out a crazy idea, and has had a huge impact on what I can do in this hobby, and even the way I think about problems.

This was the case with this is the Mobius Mini mount that I designed one evening when I was determined to get both a Mobius Mini and FPV All-in-One (AiO) cam on the Turnigy Bonsai Flying Wing. I played with lots of different positions on the plane, trying to get both the Mobius and the FPV cam in the best positions as possible.

Once I set upon the idea of putting the VTX on top of the Mobius the mount just grew out of that. It took 4 iterations until the final was created.

The mount weights around 9 grams all up when printed in PLA with 5% infill. For my non-3D printing readers that means its a basic type of plastic and the mount is practically hollow.

Being light is important, so I actually printed 5 different prototypes before settling on the final design. The Mobius Mini is 27g, so with a 9g mount this addition accounts for around 10% of the overall weight of the plane (I can't remember if that is with or without the flight battery).

All the extra weight certainly makes the Bonsai heavy nose but there is enough throw in the control surfaces to trim that out. That trade-off also makes it sits a bit more firmly in the air and doesn't get thrown around as much, plus you get HD video.

You can download the STL files on Thingiverse, where there is more detail on the design and how it is mounted to the Bonsai.
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Monday, 19 June 2017

Chasing Mustang (Video)

Following other planes in FPV is something I thought would be easy, but when I started flying this way I was surprised just how hard it is. The trick seems to be to fly in the direction that the other plane is going, along a similar trajectory, however my initial attempts were all about flying directly at the plane, which didn't give me much room to manoeuvre when we needed to change direction suddenly.

The result of much practice (this video was cut from around 30 mins of footage) is a slight improvement in an understanding of how it works.

It's really funny being on the ground and realising your neck is twisted to one side because you've been trying to look out the side of the plane to get your bearings. I might look at a head-tracker for my next FPV rig, but not for this one as the Bonsai is teensy and mine is already overloaded with the Mobius Mini and FPV gear.

Perhaps a piston engine fighter is in my future... another Corsair perhaps?

Gear used in this flight:
Turnigy Bonsai with Mobius Mini action cam, multistar 2204 with 5/4.5 prop for about 9 mins of flying time.

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Sunday, 18 June 2017

Bonsai Maiden (Video)

Setting up a new plane is always fun. The first time I flew my Parkzone Corsair it flew perfectly except had less than half the control surface throw that it actually needed to operate. I managed to circle and land, which was a miracle.

At the other end of the scale was the first time I flew my heavily-modified and very quickly built MultiPlex EasyStar, which glided in a dead straight line right off the throw, even with a brushless inrunner, ailerons and a double-size rudder.

Maidens are, therefore, always a mixed bag for me, and the Bonsai was a bit of a hndful handful. She was overpowered, overloaded, marginally balanced and way-over thrown with no expo

In short, she was a handful.

Now, looking back (this maiden was  a few weeks ago now) she is flying beautifully and is a lot of fun for a small fixed wing FPV platform.

Check out the end of the video for some maiden crashes and craziness.
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Tuesday, 6 June 2017

Bonsai in the Park (Video)

There's nothing quite like flying with friends, especially when those friends are holding your hand (so to speak) while you're learning to fly FPV fixed wing proximity.

Turns out it isn't as hard as I wanted to think it was, so aside from a few impromptu landings on the wrong side of the park (mostly due to the slightly weird 170 degree perspective from the Eachine TX02 that I'm using as the FPV camera) and a wickedly fatal crash into a rubbish bin (no, the camera wasn't rolling) the whole experience was the highlight of my flying this year.

Except for the last time I flew the Bonsai, which was also the highlight.

This Bonsai is using a camera mount that I designed which also holds the Mobius Mini, hence the decent video. You can check out the mount on Thingiverse. This means the Bonsai has an All Up Weight of over 300 grams. It doesn't make much of a difference for normal flying, but loops and rolls are noticeably exaggerated. Given that this is only the second flying session (and I'm still a little precious about breaking my planes), I think a bit more throw and and bit more exponential will iron out much of the sluggish controls... or cause the wing to snap, but that brings me to...

The Joy of Foam. Yes! You too can turn this:

In to this:

With only half a stick of hot glue, some duct tape, and an evening which you were only going to spend rolling up D&D characters anyway.

Many thanks to Mark for laughing hysterically when the wing did crash - I've learning to be less precious every day.
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