This is pretty clever. The major improvements I'd want to make are some sort of RFID chip that deactivates the magnet when I'm close enough, instead of a fingerprint scanner. It seems like anyone who gets close enough can see the scanner, so I'd prefer to have something more invisible.
And the second thing would be just to improve the lag time between grasping the handle and the deactivation of the magnet, so I can just lean down and casually grab it, instead of having to hold it for a second before bringing it up. The more magic, the better.
There are some ways that he could have improved the deactivation routine, but I thought the most clever thing was that he used a capacitance sensor to activate the magnet the moment the handle was touched. That had to greatly increase the battery life.
You could probably spin it out even with the magnet activated. The friction coefficient is probably too low for any realistic electromagnet to be strong enough to make it impossible to "slide" out.
Just try with a magnet on your fridge door. It's much easier to slide it around than it is to pull it away.
It's a bit of a balancing act between "magical" and "proper". Like it would be very easy to just have a third party control the electro-magnet via a remote control, and it would work perfectly in all situations as long as the third party was acting correctly. But it wouldn't really be a hammer that could only be lifted by one person.
Additionally having the hammer remain locked once he steps away would be a good improvement. It looks like it only locks when a person begins to clasp their hands around the handle.
Seems to me this is by design, to avoid wasting massive amounts of power when the hammer wasn't being grasped.
A Pro Mini draws a tiny amount of power, I'm talking tens of milliamps- he could leave this hammer somewhere for weeks probably without the batteries dying, with the occasional passerby trying and failing to pick it up. To manage that with the magnet running constantly would be impossible.
It's also a great safety mechanism, being stuck between an electromagnet and the metal sounds unpleasant, just shout at the guy stuck to not touch the handle and it will not hurt them!
Cool idea, terrible acting. I feel like the "wow" factor in his audience was really killed by the awkward way he made it look like he was pushing a button and waiting for something to happen, instead of struggling to "lift" the hammer while he waited for the thumbprint to register.
I knew a guy that made a lightsaber that only he could use. Part of the act was that only a "real Jedi" can activate a lightsaber. He used a neodymium ring and a hall sensor. The trick was seamless.
I agree. I think dressing up as Thor and playing up the crowd the way you suggested would have gone a long way. Also putting the fingerprint scanner where you one actually grabs the handle from, somewhere midway on the shaft, would have been a better design.
If you like this kind of stuff, check out Colin Furze's youtube channel. He does some similar experiments, and is very entertaining.
It is kind of terrifying seeing him operate so many machines with his tie dangling around his neck. He obviously knows his way a round a shop better than I do but I always thought neckties were no-nos in the shop.
Wearing them still isn't a good idea, but clip-on ties will at least break away when they get caught rather than forcing your head into some machine...
From the constant cuts to extreme close-up, I'm betting he puts on the tie and collared shirt for talking-to-the-camera shots (and one or two per episode where a machining tool is on, but he's carefully away from it) and takes it off most of the time when he's actually working.
A simple disguised mechanical switch would have worked much better. Set it up so you have to push the handle down before pulling it up to disengage the magnet for instance.
Most of the magnetic field lines are along the z-axis (up and down) so anyone could still simply slide the hammer towards the end of the metallic floor it's sitting on(like the sewer cover) and be able to pick it up then. That's how we unstick really strong magnetic targets in our sputtering system, we simply slide them off.
I was hoping that instead of magnets, it would just be extremely heavy, and be able to activate an internal gyroscopic system to do something like this: https://www.youtube.com/watch?v=GeyDf4ooPdo
It'd be pretty hard to fit all that in a small package though, and probably dangerous.
Instead of a thumbprint, he should have used a bracelet with an rfid chip, much faster response time and his hand could have been anywhere on the handle.
I'd have picked a different legend: the sword in the stone is more similar to how this works, the sword can be wielded by anyone after the king pulls it out of the stone, and this hammer can be wielded by anyone after the engineer pulls if off of the magnet. Thor's hammer can only be wielded by him, ever.
I can't help but wonder if you could beat the magnet by kicking the handle sideways, the strong impact multiplied by the lever force might be enough to beat it.
This is really neat. I wonder if there is the possibility of using a similar magnet set-up as a lock? I worry about my motorcycle being stolen since it is so easy to pick up and most locks can be broken, if I had an electro-magnet like this one it might be much harder to steal.
Magnetic force decreases with the cube of distance from the source. Which is to say that it would take a ludicrously strong magnet at arm's length to do any damage to credit cards in their back pocket.
There's some context not obvious in that video: The machine as a whole fails, yes, but the only part of it that malfunctioned was the hard drive. The rest of the electronics in there are solid-state, and won't (okay, will be, but only minutely, and not enough to cause failure) be affected by the magnet. Your cell-phone is magnet safe.
And the second thing would be just to improve the lag time between grasping the handle and the deactivation of the magnet, so I can just lean down and casually grab it, instead of having to hold it for a second before bringing it up. The more magic, the better.
Still, this is pretty awesome!