Key Controller

Mobile door lock indicator

With the Key Controller, you always know whether a door is locked or not. Since the display is placed directly on the key, you can also check if you have really locked the door when you are on the road.

The proposed invention is a device which indicates whether the door (e.g. house door) has been locked. This way you can be sure that you have locked the door and see immediately if you have forgotten to do so.

A key cap including indicator is attached to the key and an attachment made of dimensionally stable plastic is attached to the corresponding lock.

When the key is inserted into the lock, a protrusion (called a "nose") on the lock touches the field of view on the key. By locking the lock and the associated turning movement, the nose now pushes the field of view in one direction and the indicator field turns red.

When the lock is unlocked, if the key is turned in the opposite direction, the nose pushes the field of view in the other direction and the key shows green in the display field.



There are intelligent/electronic locks (e.g. Smart Lock...) which indicate the locking status of the door, but these systems always require the installation of a separate infrastructure.

The Key Controller, on the other hand, can be easily retrofitted and attached to any key and lock.

Locking state always retrievable

The key shows directly whether the lock has been locked. Even if you are unsure at a later time whether the lock has actually been locked, a glance at the key is enough to reassure yourself.


The Key Controller gives you the necessary security that your home is locked. Even when you are out and about, you can quickly reassure yourself with a glance at the key.

Cost-effective solution

Compared to extensive Smart Home systems, the Key Controller system is relatively inexpensive to manufacture and can also be installed without the need for specialist staff.

Clever system

The process works whether the key is inserted horizontally or vertically.

Furthermore, burglaries are made more difficult because people no longer forget to lock the door.

Help with compulsive behaviour

People with obsessive-compulsive disorders tend not to trust existing systems and run back many times to check whether they have been locked. This can be prevented with the handy Key Controller.

Possible uses of Key Controller


private dwelling

Regardless of whether you are renting or owning a flat: Key Controller can be easily attached to any lock, so you know your home is always well locked.

Commercial business premises

Key Controller can be installed on locks to business premises. The advantage is that the system can also be easily retrofitted to older properties.

Delivery and mounting details

Both parts, the key attachment and the lug on the lock, are delivered in one piece and are joined together in their original form by a small bar. This then breaks during the first application so that the adhesive part is also attached exactly to the lock. This ensures that the Key Controller System is not fitted out of place.

In the case of a horizontal key slot, a template is enclosed so that exact installation of the lug on the lock is also possible here.

3D Visualisations


Property rights

Utility Model Protection

Type of protection: AT Utility Model Protection
Reference number: GM45-2022
Date of registration: 13.05.2022

Main claim: Mechanical device for indicating the locking state of a lock, characterised in that it consists of a key cap (1) for placing on a key and an associated attachment (5) for placing on a cylinder lock, wherein, during the process of locking/turning the key, the lug (6) of the attachment (5) in the key (2) of the key cap (1) engages the knob (7) of the shaft-mounted (8) cylinder (4), and as a result the locking state in the viewing window (3) of the key cap (1) is changed so that "red" is indicated in the locked state and "green" in the unlocked state.

Are you curious about the invention?

Do you have any questions?

We will be happy to provide you with additional information material or clarify open questions with the inventor for you. Simply contact us and we will be happy to support you.

Contact us

JMW Innovation GmbH

jmw Innovation GmbH has been successfully implementing and marketing ideas at two locations (Salzburg/ Berlin) for over 20 years. Thanks to our many years of networking, our passion for new things and our experienced staff, we are now THE first port of call for new ideas in the German-speaking world.

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