varx @varx@infosec.exchange

I'm opening a new social alt: @varx

When i.write.codethat.sucks was collapsing in on itself, I moved all my follows and posting to infosec.exchange, which I had been using for mostly tech stuff.

But now I'm going to try separating my stuff out again a little. We'll see how it goes!

I'm starting a Social Media Design community on Dreamwidth for longer-form, more persistent discussion of what we want in social media systems:

https://social-media-design.dreamwidth.org/

Anyone who's interested in talking out new approaches, getting feedback on designs, analyzing current systems, or just plain brainstorming on how to Make Stuff Better is encouraged to join and participate.

Thinking back on times that USB plugs have been a little tough to insert or remove, I can probably answer my own question: Yes, tolerances are too small.

...but you could totally build a short, transparent plastic adapter that visually demonstrates that only the power lines are connected.

I assume that the charging circuit for the LiPo battery in the toy has some sort of limiter on how much it will draw. And I assume that the USB port on my laptop is well-behaved and won't allow drawing more than 100 mA or so.

But I also don't want to damage something.

Electronics question:

I want to splice an RC toy's proprietary charging cable with a USB cord so that I can charge it from USB instead of a ~5V battery pack.

...do I need to know anything about amperage for this? Or can I assume that both ends are gonna take care of this for me?

Doing an image search for "USB condom", I'm disappointed to discover that no one seems to have made something that is literally just a thin piece of plastic that blocks the data lines.

Are the tolerances too small for that?

Bingo! I found a USB A cord in my 'lectronics box with male and female connectors, and it's only 10 inches long. Since no one wants a USB extension cord that is less than a foot long, I suppose this thing's purpose is defined by the big ferrite choke that it sports.

I can't recall ever needing such a thing. Time to cannibalize it.

OK, I think my best option might be to cut the charging cord off of the controller and splice on male and female USB connectors. Then I can still chain those together to use the controller in a pinch, but most of the time I'd be able to charge the 'copter directly from my laptop.

OK, so this is probably for when the copter is being sold in a store, batteries included, and there's a "Try Me" button on the box that... what, lights up the LEDs or something?

Bizarre.

There's a marking on the board "TRY-ME" near the wire. I can find *one* reference to this online: https://www.youtube.com/watch?v=QKZyVGggPQ0

So... it comes with a wire connecting the helicopter and controller on these special ports, and you're then supposed to... throw it away?

all of my whats

OK what the actual.

Got the thing open. As far as I can tell, while the charging cable is connected to the full battery series via the power switch, the mystery port is... connected straight to just two of the batteries?

What kind of monster designed this thing?

(My wife points out that transformers aren't a thing for DC.)

I was hoping I could somehow manufacture a cable that would fit the port and just connect the USB power wires directly, but I checked it with a voltmeter and it has *half* the voltage of the batteries (2.7 instead of 5.4). It's active even when the controller's power switch is off. Is there a little transformer in there? :-/ I haven't found a small enough screwdriver to take this thing apart yet.

However, the controller and the copter both a *different* proprietary port with two prongs! (No cable provided.) Apparently on some models there is a port like this that 1) is supposed to be connected to USB for power, and 2) is wired directly to the battery terminals of the controller, which is weird and bad because of voltage mismatches.

I have come into possession of a crappy little Air Hogs RC helicopter. To charge it, I have to connect it to the controller via a proprietary adapter. The controller is then powered by 4 AA batteries, which I then have to recharge. This is all very inefficient!