Looking for ideas on how to activate a deadbolt electrically.

[Deeg]

Hey all, I need some advice for a project I'm looking into. I'd like to automate the lock on my front door by attaching a motor of some sort that can lock/unlock the deadbolt. I want to be able to use a key to unlock the bolt in case the power goes out so something like this is out. I could buy this system but it's expensive and I'd like to take a more DIY approach if possible.

I was thinking I could attach a server to the axle of a cheap deadbolt. The controller would be an Arduino with some inputs to determine when to lock or unlock. Are there any complexities that I'm not thinking of? Do you have any suggestions on how I could rig up a servo with a deadbolt?

 

[Sceadwian]

Got any detailed knowledge of how to make custom high strength gearboxes in a very compact form?
If you don't this is not an area you want to be meddling in. The torque required to actuate a deadbolt especially if the door is well sealed can be quiet high, a servo won't cut it. You'd have to make a custom gearbox for it.

 

[drjak]

Not sure what your idea of expensive is, but you can obtain these systems such as: **broken link removed** for a reasonable amount. In trying to come up with this to be functional and reliable from a DIY approach is probably going to run you as much if not more money. I have a keyless deadbolt system that I purchased from a local Menards store and it works quite well. Just a thought.....

Ken

 

[JayTheLockie]

you wont be able to convert a standard lock and still use a key, most electric locks that don't have a key override will unlock if the electric supply fails. Rather than find an electric lock, look for and electric latch/strike (the bit in the door frame that the lock goes into) and convert that, much simpler and cheaper.

 

[drjak]

How do you intend to activate your lock? I am guessing that since you mention a key for when the power fails, that you are intending to operate the lock normally without a key.

Ken

 

[Mike_2545]

I was playing around with the same idea and came up with this

 

[Sceadwian]

How much force does that solenoid put out Mike? The only reason I ask is every door is different, the one's at our house have weather seals on them, which require you to press on the door when you're latching the deadbolt, if you don't press on the door when you're unlocking them there's quiet a bit of friction, turning they key by hand is almost impossible, but the deadbolt you linked is much simpler, as long as the solenoid can put out enough force to pull it away from the specific lock it's in.

 

[3v0]

Sceadwian the door can be setup so the existing hardware holds the door closed. The surface mounted deadbolt can be setup to move freely.

That does not work if you intend to automate the existing lock.

 

[Mike_2545]

This video might show the strength of the solenoid, it has a pull force of 3.7lbs at 24v

 

[Sceadwian]

If you can hold it with you fingers like that, it's WAY too weak for my doors. Loud too.

 

[Mike_2545]

If you can hold it with you fingers like that, it's WAY too weak for my doors. Loud too.

Maybe your doors need adjusted to compensate for the added whether stripping.

 

[Sceadwian]

I'm not sure you understand....
In this case the weather stripping is a strip around the whole edge of the door, rubberized plastic. It's mean to SEAL, to create that seal when you close the door you compress the edging to create the seal. If the doors don't close under tension they can't seal...

You live in Ohio, you have no idea what winters are like here =) and here is not that far away. A compression seal as I'm talking about is the difference of 50 dollars a year or more on heating costs. 50 dollars a year could add an extra 12 square feet of bench material.

 

[OlPhart]

A matter of force required...

In order of low-> high: 1> motor drives leadscrew, 2> gearmotor drives leadscrew, 3> motor drives wormgear set drives leadscrew, 4> gearmotor drives wormgear set drives leadscrew.

The tradeoffs are in force vs actuation speed vs size/power. I'd go spelunking the robotics arena. G.H. <<<)))

 

[Mike_2545]

I'm not sure you understand....
In this case the weather stripping is a strip around the whole edge of the door, rubberized plastic. It's mean to SEAL, to create that seal when you close the door you compress the edging to create the seal. If the doors don't close under tension they can't seal...

You live in Ohio, you have no idea what winters are like here =) and here is not that far away. A compression seal as I'm talking about is the difference of 50 dollars a year or more on heating costs. 50 dollars a year could add an extra 12 square feet of bench material.

I know exactly what you are talking about, I have installed many feet of the same seals you mention, and I do know what cold winters are all about, we have them too =)

 

[JayTheLockie]

Mikes post is a "latch" lock not a "deadbolt"
A deadbolt has to locked and unlocked by hand, a latch lock locks its self as the door shuts. It would be a good idea to check your home insurance if you have any before you automate it as it could void your insurance if you ever get broken in to.