Timer padlocks again (new model)

[ruru67]

And for those "don't wanna escape" days, here's a little guard to prevent (easy) shimming, made from some somewhat battered aluminium tube I had lying around:

You need to slide the guard over the end of the shackle after you've put it through whatever you're locking (unless it has a particularly large hasp). Then, the easiest way in is to take the cover off the display, and then either dismantle the thing with a small screwdriver, or short the reset pad as described upthread.

To defeat that, you could peel off the display cover and epoxy it back on, first putting a bit of glue into the screw threads, and filling in the screw recesses and reset hole. Or you could make a cover with a hole in the middle to see the display through but which covers the black edges of the display (and perhaps wraps around), and epoxy that into place. With either of these of those done, and a shim-guard in place, non-destructive early removal of the lock would be very difficult.

[kinbaku]

With either of these of those done, and a shim-guard in place, non-destructive early removal of the lock would be very difficult.

Nice.
My timer padlocks arrived in Belgium according to the tracing. I just hope they don't stay at Customs for another week.

[ruru67]

So I finally dismantled one, and here's what I found. First, there are three screws: two small Philips head screws behind the display cover (as per redsonic's pics back on page 1 of this thread), and a tiny Torx head screw under the "QC" sticker beside the USB hole:

Opening it up:

Here we see the motor and cam. A little trick is that on the right of the PCB you can see a small switch - this is engaged by the latch when it opens to tell the microcontroller when it's open and can stop, wait a tick, and reverse to release (close) the latch. With the device dismantled like this, the motor and cam just goes around and around for a short time, sometimes even stopping with the cam holding the latch open, whereas when you watch the latch with the lock assembled, it clearly goes one way, pauses, then reverses - you can hear two distinct movements.

The lock body is all cast metal, as I kind of expected from the heft of the thing (but wasn't clear from redsonic's pics), while the front cover (with the PCB mounted to it, the buttons and display) is made from plastic. Everything that's in contact with the shackle is made of some kind of metal, not plastic. I don't think it will stand up to too much violence though.

While I had it open, I also shorted the reset pad with a bit of wire through the hole in the front cover (under the display cover). When I did that, the whole thing just died, as if the battery had run down. To get it to respond again, I needed to plug the USB power supply in, at which point it came back to life, fully reset (and with the H+M "emergency reset" feature re-enabled). That behaviour suggests the "reset" simply shorts the power, causing the battery protection/charge circuit to isolate the battery until it's put back on charge. If it was an actual microcontroller reset, I'd have expected it to restart immediately.

I've now epoxied the display covers back on (with extra glue in the screw and reset holes), and disabled the emergency reset. Emergency releases from now will require a great deal more violence (or a shim, if I've omitted the shim-guard)...

[kinbaku]

Thanks for opening and studying.

My 2 timer padlocks arrived today. Immediately done a test with setting them both at 2 minutes and closing one padlock only after half a minute. They opened automatically at practically the same time.
One lock is a bit harder to close than the other, but this is because I bought 2 and could compare them, otherwise I would not have known.
The thickness of the shackle is not bad for me: I can put it in all my chains and my connection between the handcuffs and ankle cuffs, so many combinations are possible.

They are now fully charging.

[ruru67]

I've found with both of mine, if you tip the shackle towards the latch hole, it tends to bind at the fixed end (away from the latch hole). You need to make sure the shackle slides straight down into its hole, so if you feel it bind, rock it back towards the fixed end and it should slide in nicely. Be gentle, force does not help at all.

If you're looking at the lock face with the shackle at the top, pushing the shackle top left to bottom right will tend to make it bind, but pushing it top-right to bottom left should close it cleanly every time.

[ruru67]

Oh, and I just found another way to open them:

Apply upward (directions assume the lock is facing you with the shackle at the top) pressure on the shackle, then tap the lock body sharply and repeatedly on the left hand side with some kind of tool. You don't need a hammer - I used a rubber coated screwdriver handle to avoid damage. Don't restrain the lock in any other way. In particular, if you put the lock body with the right side against a hard object, this won't work. Holding it in your hand is fine.

A small number of taps (and the sharper the taps, the less you need) and the lock springs right open.

I tested this with heavy objects dangling from the shackle. You want around 20 N or 4 lbf on the shackle to open it. A little more doesn't hurt, but the sort of force you can apply by jamming a couple of fingers into the shackle is fine.

This works because tapping the lock makes the lock body move sharply to the right, but relative to the movement of the body, the acceleration pushes the latch to the left, against the spring and away from the notch in the shackle. When the forces settle down, the pull on the shackle prevents the latch from moving back. Do that enough times, and the latch is pushed back clear of the shackle and it pops open. Isaac Newton wins again!

I'd note that neither this attack nor shimming work with the old style locks, because the lock mechanism uses a cam positively blocking the latch - the cam has to be rotated out of the way to allow the latch to release (at least without damaging it). The new locks however rely entirely on a spring to hold the latch closed, which means any force applied to the latch can open it. The spring can't be too strong (as it can be in a keyed padlock), because it has to be reliably retracted by a small motor.

If I was designing this, I'd use a small switch at the bottom of the latch hole to indicate to the microcontroller that the shackle has bee inserted, which would then initiate turning a cam to slide the latch into place. The same cam would then retract the latch to unlock when required. (I think a robust design would have a spring pulling the latch open, with the cam pushing back against it.)

I might be over-analysing this.

[Shannon SteelSlave]

I might be over-analysing this.

It's what we love here. It's why I had chosen you as one of the co-authors for the total review of the old style.

[kinbaku]

If you're looking at the lock face with the shackle at the top, pushing the shackle top left to bottom right will tend to make it bind, but pushing it top-right to bottom left should close it cleanly every time.

I can close the least lock good with 2 fingers, but when I listen it seems to rub against something where the shackle is pushed upwards with a spring for opening of the lock. The other padlock doesn't have this, but your comment above greatly simplifies the closing.
Fortunately, the good one contains a small black dot next to the screen so that I can distinguish both from each other well. I can use the better padlock as a last lock when I have the least freedom of movement with my hands. Because as you say yourself, you have to bring the shackle just above the shackle opening to close it easily.

[ruru67]

Yeah, one of mine is definitely more prone to binding than the other. I hadn't noticed until I tried it just now. One of them binds hard every time if you try to close it "left to right" (but is fine if you push right to left); the other you have to apply more rightwards force than is really natural for it to bind, but the effect is still noticeable.

I was a bit disappointed after discovering the tapping vulnerability yesterday - thinking about protective covers to prevent the sharp taps required to open them, but realised that for a lot of uses, such as locking a cuff to something, you won't have access to a tapping tool nor a hard surface to bang it against. And mostly those are the sorts of uses that the more robust shackle and lock body seems better suited to than the plastic/cable of the old style locks.

[kinbaku]

Yeah, one of mine is definitely more prone to binding than the other. I hadn't noticed until I tried it just now. One of them binds hard every time if you try to close it "left to right" (but is fine if you push right to left); the other you have to apply more rightwards force than is really natural for it to bind, but the effect is still noticeable.

I was a bit disappointed after discovering the tapping vulnerability yesterday - thinking about protective covers to prevent the sharp taps required to open them, but realised that for a lot of uses, such as locking a cuff to something, you won't have access to a tapping tool nor a hard surface to bang it against. And mostly those are the sorts of uses that the more robust shackle and lock body seems better suited to than the plastic/cable of the old style locks.

I mainly use them to bind my hands together or to a fixed object so that I cannot move to, for example, a rubber hammer. I tried to do it with my hand tapping on it - something that is not even possible in my bondage - but I couldn't open the lock due to the law of slowness.
What I like is that it automatically pops open. This was a requirement for the purchase. I also find it pleasant to be able to close when the time is already running: If you have to stop the bondage at a certain time, you can set it this way and however long the preparation takes, you are sure that you will stop in time. Once closed you are stuck until your end time.

[ruru67]

Yep, they're much better suited to joining things together than say locking buckles, whereas with the cable style it's pretty much the opposite way around. While I haven't done exhaustive destructive testing on either type (but I have had the cable pull out of the metal attachments on one of the plastic ones), I feel that the plastic ones are better at resisting non-destructive attack (shimming and tapping don't work), and therefore good for locking cuffs, gags, collars et c where the lock is blocking the thing from opening, but isn't under any real stress, while the new ones are more robust and can be used for securing a cuff or chain to something that might get tugged at.

I wouldn't use them in a way that your full weight is bouncing on them (but then that's true of most keyed padlocks too), but they should be fine for a spread-eagle or joining cuffs et c.

And yes, having the things pop open automatically is a definite win compared to how fiddly the plastic locks can be to get open and closed, especially one-handed. I wouldn't use one in a situation where I couldn't reach the buttons, in case you happen to be pulling on at at the moment it tries to open and it doesn't unlatch. (You do have to pull quite hard to prevent it unlatching, but I've tried this and it can happen.)

I also like the ability to start the timer before placing the lock - as well as knowing all your locks are going to pop open at the same time, and knowing when it's going to happen, there's no danger of accidentally adding time while you're installing the lock somewhere awkward and out of sight. I spent an unexpected extra hour self-gagged a while ago after unknowingly bumping the hour button on one of the old style ones...

[TNTBound]

the timer locks are awesome! i have two that i use as a release for my wrists and they are amazing. they will resist struggling, although they if there is tension on them when the time runs out, the latch will not release. in which case, you simply need to hit the lock button three times to let yourself out. absolutely love them!

[kinbaku]

the timer locks are awesome! i have two that i use as a release for my wrists and they are amazing. they will resist struggling, although they if there is tension on them when the time runs out, the latch will not release. in which case, you simply need to hit the lock button three times to let yourself out. absolutely love them!

I'm having a lot of fun with them. I always keep them in the lock-position so I have to open them before I start. It happened to me one time that one padlock had a completely flat battery even though I hadn't used it for a long time. Now it was just starting a little later with the self-bondage to fully charge it again. Better that than getting stuck if one padlock breaks while the other has a flat battery (Murphy's law).

[gogglestars2]

Going back to the original plastic locks with cable, the reason the cable can be pulled out with enough force is that it's attached to plastic. The case closes around it, there's no screw or other strengthener. Knowing this may not help in the least if you can't get any leverage

[ruru67]

I've found that what fails isn't the plastic case, but the cable pulling out of the metal fittings. The crimps just aren't all that strong. I've had two do that; one pulled out accidentally, the other I wanted to verify that at a pinch the things could be destroyed by turning the lock so the cable twisted on itself (the lock itself had a faulty battery, so was ripe for a destructive test).

I posted about it here.

I note that it looks kinda like the plastic coating was crimped in with the cable, so the crimp was relying more on the strength of the plastic than the steel.