5 ms·

Never mind mechanical reliability - the fact that it's an outright replacement concerns me. I wonder what the behaviour would be if I hooked a car battery up t

Never mind mechanical reliability - the fact that it's an outright replacement concerns me. I wonder what the behaviour would be if I hooked a car battery up to the exterior lock... not a concern with the previous, electrically disconnected from the exterior, model. Oh, and how well it fares when rain gets in it.

paulgerhardt 12y ago
An outright replacement acutually makes for a more robust product as we can control all the variables (how much rotation, how much force, and so on.) The previous version of Lockitron had to work in an unconstrained environment (vastly different characteristics for different kinds of locks Lockitron would fit over.) Think of it as parsing clean vs dirty data. Also with the car battery example, where are you hooking up what? Electricity follows the path of least resistance. If both jumpers are connected to the outside of the metal deadbolt, you're not going to affect the interior. You would need one jumper on either side of the door to do what I think you have in mind.
- milkanic 12y ago
  The exterior and interior of the door handle are the same wire as far as electricity is concerned - there is no resistance between them. It's not like it's going to magically unlock but the motor will be toast.
  - paulgerhardt 12y ago
    Yes, in theory because the two surfaces are connected they are one wire, but in practice metal does not have a non-zero resistance until you get down to absolute zero temperatures. This subtlety is what allows one to do something neat like this: https://www.youtube.com/watch?v=fPoomwdNZeY https://www.youtube.com/watch?v=fPoomwdNZeY - on their build log you can see the musician does accidentally hurt himself from time to time when bits of his chain-mail don't make for complete coverage but he never goes into cardiac arrest. The current allows goes for the shortest, least resistant path to ground. A similar effect is also what determines survival rates in lighting strikes. If the current passes through the brain it can arrest breathing, or through the heart and it can cause arrhythmia. If it just passes through a smaller area like a finger it can do more local damage but you'll survive. This is despite your body being 70% water or the equivalent of 'the same wire.' If you wanted to "shock" Lockitron's motor you would need to ensure the motor is in the current path - this is pretty difficult as it's isolated in a plastic container with only two wires grounded it with the pcb, itself mounted in plastic.
  - hueving 12y ago
    And how exactly do you attach one of the car battery cables to the inside handle if the door is locked? The point is that touching both cables to the front will result in the shortest path between the cables, which goes through nothing useful.
maxerickson 12y ago
If you are willing to damage the lock to get in you might as well use a sledgehammer. Or epoxy if you want to vandalize it. (I'm not recommending those activities, just pointing out that the car battery is pretty hypothetical)
- Jochim 12y ago
  Car battery would be much less obvious as a form of vandalism though, unless you were caught in the act.

paulgerhardt 12y ago

An outright replacement acutually makes for a more robust product as we can control all the variables (how much rotation, how much force, and so on.) The previous version of Lockitron had to work in an unconstrained environment (vastly different characteristics for different kinds of locks Lockitron would fit over.) Think of it as parsing clean vs dirty data. Also with the car battery example, where are you hooking up what? Electricity follows the path of least resistance. If both jumpers are connected to the outside of the metal deadbolt, you're not going to affect the interior. You would need one jumper on either side of the door to do what I think you have in mind.

milkanic 12y ago
The exterior and interior of the door handle are the same wire as far as electricity is concerned - there is no resistance between them. It's not like it's going to magically unlock but the motor will be toast.
- paulgerhardt 12y ago
  Yes, in theory because the two surfaces are connected they are one wire, but in practice metal does not have a non-zero resistance until you get down to absolute zero temperatures. This subtlety is what allows one to do something neat like this: https://www.youtube.com/watch?v=fPoomwdNZeY https://www.youtube.com/watch?v=fPoomwdNZeY - on their build log you can see the musician does accidentally hurt himself from time to time when bits of his chain-mail don't make for complete coverage but he never goes into cardiac arrest. The current allows goes for the shortest, least resistant path to ground. A similar effect is also what determines survival rates in lighting strikes. If the current passes through the brain it can arrest breathing, or through the heart and it can cause arrhythmia. If it just passes through a smaller area like a finger it can do more local damage but you'll survive. This is despite your body being 70% water or the equivalent of 'the same wire.' If you wanted to "shock" Lockitron's motor you would need to ensure the motor is in the current path - this is pretty difficult as it's isolated in a plastic container with only two wires grounded it with the pcb, itself mounted in plastic.
- hueving 12y ago
  And how exactly do you attach one of the car battery cables to the inside handle if the door is locked? The point is that touching both cables to the front will result in the shortest path between the cables, which goes through nothing useful.

maxerickson 12y ago

If you are willing to damage the lock to get in you might as well use a sledgehammer. Or epoxy if you want to vandalize it. (I'm not recommending those activities, just pointing out that the car battery is pretty hypothetical)

Jochim 12y ago
Car battery would be much less obvious as a form of vandalism though, unless you were caught in the act.