About this item
The Bosch DS150i is a passive infrared request to exit detector -a REX sensor -designed specifically to release a door lock when someone approaches to leave. It picks up body heat and motion in front of the door, signals your access control panel or door controller, and the door unlocks. No button to push, no card to wave. You just walk up and the door releases. That's the entire job of a REX detector, and the DS150i is one of the more reliable ones for access-controlled interior openings.
If you've been searching "bosch rex" or "bosch motion rex" -REX is the abbreviation for request to exit. It's the standard term in access control for this category of detector. The DS150i is Bosch's dedicated REX product, not a repurposed burglar alarm motion detector. It's built from the ground up for door control applications, which is why it carries a UL 294 listing for access control devices, not just a general motion sensor listing.
What First Step Processing Actually Does
The one line on every competitor's product page is "First Step Processing (FSP) allows virtually instant response to human targets." Nobody explains what that means in practice.
Standard PIR detectors need to see motion across multiple detection zones before they trigger. That delay prevents false alarms but also means there's a brief hesitation between walking up and the door releasing. In a busy corridor or a loading dock, that lag is noticeable. First Step Processing is Bosch's algorithm that distinguishes a human heat signature from environmental noise quickly enough that the detector triggers almost immediately when a person enters the coverage zone -without giving up the false-alarm resistance you need to stop the detector from releasing the door every time a cart rolls by or an HVAC vent cycles on.
Coverage and Mounting
The DS150i covers 8 feet by 10 feet (2.4m x 3m). It mounts on a wall or ceiling, and the internal vertical pointability lets you adjust the aim after mounting without moving the base -useful when the door clearance or your mounting location isn't perfectly centered on the door. The wrap-around coverage pattern matters for door control specifically because people don't always approach a door straight on. They come from the side, from an angle, carrying things. A narrow beam sensor misses them. The wrap-around pattern catches people approaching from a wider arc, which reduces the awkward pause of standing at a door waiting for it to figure out you're there.
It works for single or double doors from the same unit.
Fail-Safe vs Fail-Secure: You Pick
The DS150i lets you set the power loss default mode to fail-safe or fail-secure, depending on how your door is controlled. Fail-safe means the relay opens on power loss -the door goes unlocked, which is what you want on most egress paths. Fail-secure means the relay stays closed -the door stays locked, which is correct for high-security openings where an unlocked door on power failure creates a security problem rather than a safety one. Setting this at the detector level means you can match the detector behavior to your lock type without relying entirely on the access control panel configuration.
The timer mode is also selectable -reset mode accumulates motion detections and holds the relay open as long as motion continues, non-reset mode ignores additional motion events once the latch timer starts counting. The relay latch time is adjustable up to 60 seconds.
Specifications
Model: Bosch DS150i (white/light gray)
Black Version: DS151i
Type: PIR request to exit detector
Coverage: 8 ft x 10 ft (2.4m x 3m)
Mounting: Wall or ceiling, surface mount
Alarm Output: Two form C relay contacts
Relay Latch Time: Adjustable to 60 seconds
Timer Mode: Accumulative (reset) or counting (non-reset), selectable
Power Loss Default: Fail-safe or fail-secure, programmable
Voltage: 12VAC/VDC or 24VAC/VDC
Current Draw: 26mA at 12VDC
Indicator: Single activation LED
Dimensions: 6.25" L x 1.5" W x 1.5" D
Enclosure: High impact ABS plastic
Operating Temperature: -20°F to +120°F (-29°C to +49°C)
Listings: UL 294 (access control), ULC-S319
Use: Interior only
American Locksets has stocked Bosch access control sensors since 2001.
Trusted Since 2001
.svg)
