ᐅ Electronic front door with fingerprint access

You mean an automatic lock with an electric strike.

If you want to prepare for this, it’s important to run power to the door to operate the strike or motorized lock. The rest of the system works at the facade (fingerprint reader) and its control unit.

Be careful with systems from the well-known German manufacturers. There are definitely systems that can be easily bypassed. That’s ridiculous.

I’m not sure what the exact technical term is. I mean a lock where the door locks automatically, as if you were always locking it with a key. Is that an automatic lock with an electric strike? What exactly is the electric strike? Is it the fingerprint reader?

I’m aware of the need to bridge the system, and it’s still on my to-do list. I’ve only read that there are safety relays for this purpose. I don’t know the details. But you seem to know more... Which “well-known” manufacturers are you referring to? What exactly is the issue? What does the solution look like?

These are three different things:

- Automatic lock: mechanically locks the door when it is closed, so the door is considered locked (possibly combined with an electronic motorized locking mechanism)
- Motorized lock: electrically unlocks the door lock when triggered, allowing the door to be opened just like turning a key
- Fingerprint reader / keypad / card reader, etc.: does not open the door itself, but sends a signal to the motorized lock. In older and cheaper systems, this signal was simply generated by closing an electrical contact. If you removed the unit and shorted the control wires, it would trigger the lock. Today, it works via a separate control unit, so shorting the wires is no longer effective.

Christian K. schrieb:

I’m not sure about the exact technical term. I mean a lock where the door locks automatically, as if you were always locking with a key. Is that an automatic lock with an electric strike? What exactly is the electric strike? The fingerprint reader?

I’m aware of the concept of bypassing and it’s still on my to-do list. I’ve read that there are safety relays for this purpose. I don’t know the details yet. But you seem to know more... Which "well-known" manufacturers are you referring to? What exactly is the problem? What does the solution look like?

The automatic lock basically works mechanically and extends two additional bolts when the door closes. From an insurance perspective, the door is considered locked at that point. An automatic lock does not lock by turning like a key would. That’s what a motor lock does. Motor locks are more expensive and less reliable than automatic locks, so I would not recommend them.

The electric strike electrically retracts the bolts extended by the automatic lock as well as the latch, just like pressing the door handle. The electric strike only needs a power impulse for that. How that is triggered is secondary. The main point is that power is available in the door and leads, for example, to the electrical distribution. You can then connect whatever you want there, such as a control unit from eKey, a relay, or something else.

The fingerprint reader just sends a signal to its control unit when a finger is positively recognized. That’s all it does—and that’s actually a good thing. Some systems from well-known manufacturers simply close a contact when a valid fingerprint is detected. If you tamper with the reader and bridge the contacts, the door will open just the same. That’s as clever (and secure) as an ignition lock from the 1960s. For example, eKey handles this smarter by having the fingerprint reader not directly control the electric strike (or motor lock) but connecting through a control unit. The communication between the fingerprint reader and control unit is encrypted. Simply bridging the contacts won’t open the door.

We installed a Fuhr motorized lock in the front door along with the FSB handle. From the door, there is a power cable plus two additional cables running to the electrical panel, where the Ekey control unit is installed. Conveniently, when closing the front door, I can simultaneously open the garage door.

This is a great solution if you, as the homeowner, are knowledgeable and able to assert yourself against the specialist tradespeople. However, finding someone who could work with a control unit located outside the door was a major challenge. I received a rough quote that was unaffordable. In the end, I purchased the handle myself, persuaded the door installer to cooperate, and did the rest on my own. Still, the motorized lock, handle, and Ekey technology cost around 2500–3000 euros without the front door, plus a similar amount in labor time.

Thank you for the explanation. For me, an automatic lock and a motorized lock were the same. To clarify:
Option 1: Automatic lock with an electric strike, since with only an automatic lock, ekey cannot open the door.
Option 2: Motorized lock

I now need to clarify what was offered to us.

@sla83
I don’t quite understand why the professionals were against it and especially why it cost 2,500–3,000€. It might be due to the handle, but we have an offer for ekey with a control unit installed in the door for 1,300€. A second offer is similar. There is also the option to install just the lock. That costs about 600–700€. The ekey would be connected at the doorbell, and the control unit would be installed in the sub-distribution panel. Costs:

Lock: 650€
ekey: 500€
Control unit: 300€
KNX integration: 400€
Total: 1,850€