SimpliSafe is one of the most popular DIY home security systems on the market, and for good reason — it’s genuinely easy to set up. The Entry Sensor is the most common component in any SimpliSafe system, and most people have several of them covering doors and windows throughout their home. This guide covers how to mount them correctly the first time, where to place them for maximum effectiveness, and a few clever use cases beyond standard doors and windows.
How the Entry Sensor Works
The SimpliSafe Entry Sensor has two parts. The larger piece houses the wireless communication technology and the pairing button. The smaller piece is a magnet. When a door or window opens and breaks the magnetic connection between the two pieces, a signal is sent to your SimpliSafe base station. Both pieces mount separately — typically the larger sensor on the door or window, and the magnet on the door frame or window sill — and the two pieces must be within 1.5 inches of each other when the door or window is closed.
It doesn’t technically matter which piece goes on the moving part and which goes on the fixed frame — either configuration works. Most people find it easier to put the larger sensor on the door frame and the magnet on the door itself, since the frame is more stable for mounting.
Adhesive vs. Screws: Which to Use
Each piece of the sensor comes ready for both mounting methods — adhesive strips on the back and screw holes on the bracket. Here’s the honest difference between the two:
Adhesive is faster and leaves no holes. It works well on smooth, glossy surfaces like vinyl window frames, smooth-painted trim, and metal doors. The stock adhesive strips tend to perform poorly on flat or matte-painted drywall — the bond just isn’t strong enough over time. A sensor that falls off while your system is armed will trigger the alarm, so this matters.
Screws are more reliable, especially on wood doors, door frames, and drywall surfaces. A pilot hole isn’t necessary for most installations — SimpliSafe’s own support team confirms you can drive the included screws directly with a Phillips head screwdriver. If you want to drill a pilot hole, use a 3/64″ bit.
Step-by-Step: Adhesive Installation
- Clean the mounting surface thoroughly with a dry cloth to remove dust and debris. If possible, wipe with isopropyl alcohol and let it fully dry — any residue will weaken the bond.
- Peel the wax backing off the adhesive strip on the sensor bracket.
- Press the bracket firmly against the surface and hold it for 30 seconds. SimpliSafe recommends this dwell time to ensure a good initial bond.
- Slide the sensor body down onto the bracket until it clicks into place.
- Repeat for the magnet piece, positioning it on the opposing surface so both pieces are within 1.5 inches of each other when the door is closed.
Step-by-Step: Screw Installation
- Slide the sensor body off the bracket to expose the mounting holes.
- Hold the bracket in position and drive the two included screws through the holes into the surface.
- Slide the sensor back onto the bracket.
- Repeat for the magnet piece.
Special Case: Metal Doors
If you’re mounting to a metal door, SimpliSafe recommends placing a thin piece of cardboard between the sensor and the metal surface. Metal can interfere with the magnetic bond, and the spacer prevents false readings. Similarly, if your door frame itself is magnetic, place the smaller magnet piece on the magnetic surface rather than the sensor body.
Pairing the Sensor to Your System
Once both pieces are mounted with the door or window closed, it’s time to add the sensor to your SimpliSafe system. Open the SimpliSafe app, go to Add Device, and press the small button on the larger sensor piece. The system will recognize it and prompt you to give it a name or location. You can also do this through the keypad by entering your Master PIN and navigating to Add Device.
Using Entry Sensors Outdoors
Here’s something most people don’t realize: SimpliSafe Entry Sensors have a range of 400–500 feet, which means they can be used outdoors — on a gate, a shed door, or even a mailbox. The catch is they aren’t weatherproof on their own. A weatherproof enclosure for SimpliSafe Entry Sensors solves that problem. It’s a protective case that keeps the sensor dry and protected from the elements, with a plug seal to keep moisture out. Battery access is easy. It’s a clever way to extend your coverage well beyond the interior of your home.
Using Entry Sensors on a Garage Door
A standard entry sensor isn’t designed for the curved, moving surface of a garage door panel — the gap and angle make alignment tricky. A purpose-built garage door bracket for SimpliSafe Entry Sensors solves this cleanly. It holds the sensor at the correct angle for reliable detection, includes both adhesive and screw mounting options, and is built to handle the vibration of regular garage door use. It’s a much cleaner solution than trying to improvise with the stock mounting bracket.
If the Adhesive Fails
If a sensor falls off or you need to reposition it, the original adhesive strips are single-use and won’t re-stick. You have two options: use the screws going forward, or replace the adhesive. Pre-cut replacement pads made specifically for SimpliSafe sensors are available on Amazon and are a significant upgrade over the stock strips — the VHB formula holds considerably better on painted surfaces.
