Prop-Guards

To anyone building drones the absence of prop-guards might raise warning flags, and so I've addressed the issue with spars borrowed from the mono-ski and an 8' length of dowelling from the timber yard around the corner. Yes, I could have used carbon-fibre but no, I can't be arsed.

Wire My Even Bothering?

...after an entire afternoon trying to get a motor to talk to a F(uck)UTABA transmitter?

Achilles heel seems to be the lack of instruction from the suppliers, which frankly could have stayed in the mandarin without making a difference on the day.

Principally the side of that ESC that you need to see is hidden from view, beside the fact the single lead emerging from it bears no relation to the five wires that do.

Thankfully (and doubtless reluctantly) there's a video now from which the lower image is cut. Looking at it, I realise with Dumbledore's hat on what I may have been missing.

The text accompanying the upper image appears to say the throttle is calibrated after two beeps from a motor connected to receiver Port 3 (which is normally attributed to throttle settings).

An addendum however suggests this is much too easy for the 80A ESC, which must presumably be programmed with the three wires marked 'Programming' on the video.

Your mission Jim, should you choose to accept it, is to find out which port that plugs into and then try again.

Three takeaways from this though:

Firstly I spent a lifetime flying airliners, something that when made as complicated as possible was considered a positive virtue by its proponents.

Secondly I'd a brush with computing, which all now agree should be made as simple as possible if we're going to buy millions of smartphones every day.

Thirdly, Chinese firm DJI captured 80% of a global market by making drones fly out the box.

Management guru Peter Drucker suggests the role of companies is to organise things for us so that we don't have to: and why you sleep securely at night whilst I grapple with this shit.

Many of you ~ yeah, right ~ will have been wondering what a yellow Return Back Wire could possibly do. ESCs basically send broad-brush instructions down the line to fast motors like these that drive propellers, but require information in return from motors operating relatively slowly like those driving RC cars.

Santa Ditches Donner...

... und Blitzen in time for '25 deliveries.

One Small Step-Motor for a Man #2

Let's look at connecting an RC transmitter to a receiver. And take the gum out of your mouth.

First thing to note that ~ designed by nerds for nerds ~ it's not obvious how to turn it on. It's either of the two chrome switches in the middle. Don't ask why there's two... just be happy that the light comes on.

First thing to note is that the Futaba 'Secret Squirrel®' HOME/EXIT key necessary to return to the system screen is that chrome strip on the left, just below the side-stick.

The side-stick here controls the throttle, and as a safety feature this should be left closed (lower stop) throughout, which is to stop people from inadvertently turning on things so that the motor and propeller elsewhere take out a bystander's finger.

Of most interest here is the TX (transmitter) voltage top right. Run this down and the cat will sail off into the sunset of its own accord.

Ignore the SYSTEM menu, and the MODEL select. The latter allows nerds to use the TX with a range of different types, whereas thankfully we'll be dealing with only one.

Instead press the LINKAGE menu-pick, with a side order of fries. With more options on this next screen than a Chinese takeaway, we need only SYSTEM TYPE.

According to 'Chip' on the FUTABA video, five time aerobatic champion, our receiver is an 18-channel FASSTest type, with built in telemetry like an F1 car. This means it can send data back to you like the afore-mentioned onboard voltage level.

Pressing this, and then the LINK button, should connect the receiver. Doing this while the RX was powered up, the TX was not a happy bunny ~ may just be me, but you may have to power up the RX after initiating the process.

Once this is done ~ you'll agree it's not rocket science ~ the screen below appears.

Note that it provides the Receiver ID, which sadly cannot be personalised. Also shows the voltage (3.8V and not the 5.0V I guessed at tho' the RX will run on a range of some three to six volts).

It also provides the BFS voltage, which is not the big friendly giant but the status of the batteries powering the receiver. Should it drop below par, the throttle will shut the power down and stop the boat.

D/L is download interval for data, you can speed this up at the cost of the control data being sent up-link, but like... who cares?

More exciting is the fact that it says SINGLE up there, which can be switched to DUAL or DIVORCED.

This affects us, as it affects the TELEDRONE as I'd like each pontoon to be a snap-on module that's self-contained with its own battery, RX, ESC, motor and propeller... and this may be a means of sending control signals to an RX on each drivetrain.

It's not knowing that makes life exciting, just like Christmas Eve.

But turn it all off now, and go to bed:

Hobbywing X-8

Referring to the airboat seen in the previous post-but-one and speculation regarding the motor in use, it turns out it was the above. I guessed looking at it that it was on a par with T-motor's U13 that I've used on unmanned drones, though in fact it is nearer half the power... which is good news for the prospects of an uncrewed cat in terms of its potential speed and the required power.

(Note the X-8 integrates the speed controller and indeed supporting arm in a package, much like how personal computers evolved from separate electronic components into the laptop I am using here today. Expect this to be one of the more exciting trends in 2025, but don't whip yourself into a frenzy over it...

One Small Step-Motor for a Man #1

... one giant leap for drone-kind. This is an RC receiver, and whilst they come as small as a finger-nail nowadays they still need a pair of antennae that any cockroach would be proud of.

The receiver operates like all RC currently (geddit?) on 2.4GHz, or UHF radio-waves. I last used these as a cadet in the RAF, because the military use UHF communications whereas airliners use VHF.

(I was shocked to discover that TV remotes operate at over 5 GHz ~ or SHF ~ tho' they use infrared light which to my mind is cheating.)

Note the dedicated battery ~ whose voltage I've forgotten but I do recall electronics runs generally on 5V DC ~ which has to be plugged in to the last port on the receiver, marked 8/SB because there are eight of them and SB because it's a serial bus that requires only a single wire. You remember those printer cables that looked like strips of lasagne? They were parallel buses, which have fallen out of favour.

Can I connect the plug the wrong way around? "Yes we can!" as Bob the Builder would say, and the only way of telling is that the green LED power-up light remains off.

Note there is a socket at the end of the R7008SB (catchy name, could be a BMW) for a voltage meter that transmits voltage back to the operator holding the transmitter. It doesn't say WHOSE voltage it is transmitting, as there may be separate batteries for the receiver and for the motors... you're just supposed to know, or risk ridicule at the annual RC-nerd convention over ginger beers.

Why though is knowing the voltage important? For you can run the motors and all else onboard from the same battery-pack, but then you need a distribution board, known to electrical engineers and pilots as a 'bus'. (And if you pronounce it 'bus' not 'buzz' you'll be paying for the ginger beers all night).

Well the Achilles Heel of the state of the art batteries that the modern world runs on is that if the voltage falls below a certain threshold i.e. flat, then you've to throw them away. Phones, cars and laptops use a BMC (Battery Management Computer tho' it used to mean British Motor Company in the age of empire) to prevent this from happening.

Tho' whilst you're driving the TELEDRONE, that BMC is going to be you.

© Colin Hilton, BMC.

The Joy of Esc

Another in the series of 'If I can do it, anyone Nobel prize-winning physicist can'.

So with a new year upon us, it's time to go large or go home. Our first objective is to connect an RC transmitter, receiver, electronic speed controller (ESC) and motor in a meaningful way.

Accordingly I provide the instructions from Flame (bad name for an electrical device if ever there was one), to see if you can figure it out before I can. It applies to all known Flame ESCs in the universe, but turning to your text-books note that ours is the 80A.

Top tip ~ modern motors use the ESC to draw a DC current and deliver it like an AC so as to drive a motor that no longer requires a split-ring commutator as it did during my physics classes.

Top takeaway ~ the ESC essentially governs the power delivered the motor by virtually throttling it. As you may recall from those same physics lessons, restricting electrical currents invariably produces heat and therefore ESCs have proven MORE reliable when operating at full-chat (much like reciprocating aero-engines are designed to do, unlike their cousins in automobiles), because this is when they're needing to work less hard.

N.B. It's not the most legible, tho' the bare bones also appear here:

https://robu.in/wp-content/uploads/2021/10/Flame-ESC_merged-1.pdf