August DoorSense 2nd Gen: Improved Magnetic Position Sensor

The August DoorSense 2nd Gen is a wireless magnetic door position sensor designed to work with August smart locks. It replaces the original DoorSense with improved magnetic sensing, three distinct door states, and a noticeably faster response time. At around $25 sold separately, or included in several current August lock bundles, it's the missing piece that makes auto-lock genuinely safe to use.

Without a door sensor, a smart lock can throw the bolt while the door is cracked open. That's a real problem. The DoorSense 2nd Gen solves it by telling the lock exactly what position the door is in before any locking action fires.

What Does the August DoorSense 2nd Gen Actually Do?

The DoorSense 2nd Gen detects three door states: open, closed, and ajar. That ajar state is the key upgrade over the original. Earlier magnetic sensors could distinguish open from closed, but the gap in between went undetected. With the second-generation sensor, the August app knows when the door is sitting at an angle, and auto-lock won't engage until the door reads fully closed.

Response time is measurably faster than the first generation. In practice that means the app updates within a second or two of the door moving, rather than the 5-10 second lag some users reported with the original sensor.

How the Three States Work

• Open: door is clearly not latched, gap detected by the magnetic sensor
• Ajar: door is partially closed but not seated in the frame
• Closed: door is fully shut, magnet and sensor are aligned within spec

The ajar detection relies on a calibrated magnetic field threshold rather than a simple binary switch. August doesn't publish the exact field strength spec, but the sensor ships pre-calibrated and pairs wirelessly to the August lock during setup.

Installation and Compatibility

The DoorSense 2nd Gen mounts on the door frame using the included adhesive strip or the small screw mount. A matching magnet mounts on the door edge. The two pieces communicate magnetically, no wires, no batteries in the sensor itself. Power comes from the August lock it's paired to.

Pairing happens through the August app and takes under two minutes. The sensor is compatible with any August smart lock that supports DoorSense, which includes the Wi-Fi Smart Lock Pro (ASL-05), the August Smart Lock (4th gen), and most recent models. Older first-generation August locks from 2014-2015 do not support DoorSense at all.

The mounting hardware fits standard door frames up to around 7/8 inch gap between the door edge and frame. Thicker doors or unusual frame geometries occasionally need adjustment to the magnet position for reliable detection.

Auto-Lock Integration

The DoorSense 2nd Gen enables a safer auto-lock behavior. Without it, auto-lock fires on a timer regardless of whether the door is actually shut. With the sensor installed, the August lock checks door state before engaging the deadbolt. If the door reads ajar or open, auto-lock waits. This prevents the deadbolt from jamming against the frame. A problem that can damage both the lock and the door over time.

You set the auto-lock delay in the August app, anywhere from 30 seconds to 30 minutes. The lock won't start that countdown until DoorSense confirms the door is closed.

Alexa and Smart Home Notifications

The DoorSense 2nd Gen feeds door state data to the August app, which in turn surfaces that data to connected platforms. Alexa can announce when the front door has been left open for more than a set time. You configure this through the Alexa app using the "Announce" routine action tied to the August lock's door sensor status.

August's Alexa integration documentation covers the routine setup in detail. Google Home and Apple HomeKit also receive door state updates through the August lock, though notification options vary by platform. HomeKit exposes the door state as a contact sensor, which you can use in any HomeKit automation as a trigger.

DoorSense 2nd Gen vs 1st Gen: What Changed

The original DoorSense sensor shipped with the August Smart Lock Pro starting around 2017. It worked on a two-state system and had slower Bluetooth update intervals. The 2nd Gen improves on four points:

• Three-state detection (adds ajar)
• Faster state reporting to the app
• Improved magnet alignment tolerance (works reliably at slightly wider gaps)
• Updated mounting hardware with a more secure adhesive option

If you already have a working first-gen DoorSense and it's reading reliably, there's no urgent reason to replace it unless you want the ajar state or are seeing slow update times. The upgrade makes more sense when buying a new lock or replacing a sensor that's drifted out of alignment.

Reliability and Common Issues

Magnetic door sensors are simple by design, and the DoorSense 2nd Gen is generally reliable. The most common failure mode is misalignment after the door settles. Wood expands and contracts seasonally, and a sensor calibrated in summer can read incorrectly in winter. If you get false "open" readings on a closed door, nudge the magnet position on the door edge a few millimeters toward the sensor.

Adhesive failures are the second most reported issue. The included tape holds well on painted surfaces but can release from rough or dusty frames. The screw mount option is more permanent and worth using on exterior door frames that see temperature swings.

August's support page has a DoorSense calibration walkthrough that covers both alignment and the app-side recalibration step if the sensor starts reading inconsistently.

Is the DoorSense 2nd Gen Worth It?

At $25, the DoorSense 2nd Gen is one of the cheaper smart home accessories that delivers a concrete safety benefit rather than a convenience feature. Auto-lock without a door sensor is a liability. With the sensor in place, auto-lock actually does what users expect it to do: lock the door when it's closed, not on a timer regardless of door position.

If you're buying a new August lock, check whether DoorSense is included in the bundle before ordering separately. Many current August lock packages include the 2nd Gen sensor. If it's not in the box, the $25 add-on is worth it.