Door Knob Alarm

The Door Knob Alarm does two jobs from one small device. Hang it on a door knob and it monitors for vibration automatically — any touch on the knob triggers a 120dB alarm instantly without any setup or arming sequence. Take it off the knob and carry it as a personal alarm — pull the metal chain and the same 120dB siren activates to deter a threat on the go. No wiring, no installation, no tools. One 9-volt battery required, not included. Measures 4¼" x 2¼" x 1".

Door Knob Alarm Features and Specs

• 120dB vibration alarm: Triggers automatically when the door knob is touched — no arming sequence required after hanging
• Personal alarm mode: Pull the metal chain to activate the siren when carried on your person
• Hang-on installation: Loops over any door knob on a non-metal door in seconds — no wiring, no screws, no tools
• Non-metal doors only: Works on standard wood, fiberglass, or hollow-core doors with metal knobs — not compatible with metal doors
• Compact and portable: 4¼" x 2¼" x 1" — packs easily for travel
• Power: One 9-volt battery (not included)

The vibration sensor is what makes this practical for travel — it doesn't require programming, pairing, or calibration. Hang it on the hotel room door knob before bed and any attempt to turn the knob sounds the alarm immediately. The same unit that secured the door the night before goes in the bag in the morning and onto a wrist chain if needed during the day. For travelers who want door security at every accommodation without carrying multiple devices, one unit handles both scenarios.

Door Knob Alarm for Travel Security — How It Compares to Other Door Alarms

Door alarms fall into two categories: wedge alarms that block the door from opening and vibration alarms that detect the attempt before the door moves. The door knob alarm is the latter — it alerts you the moment the knob is touched, before any entry is made, which gives more response time than an alarm that triggers when the door is already opening. The trade-off is that it doesn't physically block entry the way a wedge does. For maximum hotel room security, pairing this with a door stop alarm covers both detection and physical resistance — the knob alarm warns you, the wedge slows any forced entry.

Will this work on any door knob?

The door knob alarm works on standard metal door knobs mounted on non-metal doors — wood, fiberglass, and hollow-core interior doors that are standard in hotel rooms, motel rooms, and most residences. The vibration sensor detects movement transmitted through the metal knob when someone touches or turns it from outside. Metal doors are not compatible — the door material, not the knob, is the limiting factor. Most hotel room and interior residential doors are wood or hollow-core, so compatibility is rarely an issue for the most common travel and home use cases. If you're unsure, the hang-on design makes it easy to test before relying on it — hang it, touch the knob lightly, and confirm the alarm triggers.

Can this be used as a personal alarm away from the door?

Yes — the metal chain on the unit functions as a pull-to-activate personal alarm trigger when the device is carried rather than hung on a door. Loop the chain around your wrist or attach it to a bag and pull to sound the 120dB siren. The same output that alerts you to a door intrusion is loud enough to draw immediate attention in a parking lot, on a trail, or in any public space. At 4¼" x 2¼" x 1" it is larger than a dedicated keychain personal alarm, so it carries better in a bag than on a keyring. For a more compact dedicated option for daily carry, the keychain alarm with light is the smaller single-purpose alternative.