Sentinel Beacon — ByStander
ByStander
★ New · Coming 2027

Meet the
Sentinel Beacon.

A discreet, tamper-resistant wearable that summons help two ways: automatically when it detects danger, and silently with a hidden manual trigger when you can act yourself. No app to open. No visible panic button to give you away.

Notify Me at Launch → How it works
ByStander Sentinel Beacon prototype
Why a beacon?

When your phone can't help you.

A phone in your pocket only protects you if you can reach it, unlock it, and open the right app. Sentinel Beacon protects you when you can't.

⚡

Instant, hands-free

An impact, a fall, a sudden stop — Sentinel detects it and triggers your incident automatically. You don't have to do anything.

🔒

Tamper-resistant

If someone tries to remove or destroy the beacon, that itself triggers an alert. It can't be silently disabled.

💎

Built to be worn

Jewelry-grade aesthetic. Comfortable for all-day wear. Discreet enough to forget you have it on — until you need it.

How it works

Four ways Sentinel
keeps watch.

Sentinel pairs with the ByStander app on your phone over Bluetooth and uses on-device sensors to recognize danger patterns. When something happens, your full incident response activates — advocates, contacts, GPS, video.

📉
01 · FALL DETECTION

Hard impacts and falls

Sentinel's accelerometer recognizes the signature of a fall or violent impact. If you don't acknowledge it within 15 seconds, an incident triggers automatically.

🚨
02 · SUDDEN MOTION

Abnormal struggle patterns

Sustained, abnormal motion — the kind that happens during a struggle or assault — triggers a silent alert without you needing to press anything.

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03 · TAMPER ALERT

Forced removal

Removing or destroying the beacon raises an immediate emergency. An attacker can't take it off you to silence the alarm.

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04 · HIDDEN TRIGGER

Silent manual activation

When you can act but can't reach for your phone, a hidden trigger on the beacon silently launches your full ByStander incident — live GPS, audio, video, advocate, and contacts — with no visible signal to an attacker.

Specs at a glance

Engineered to be worn.
Engineered to be missed.

Every detail of Sentinel is built around one goal: to disappear into your day until the moment you need it.

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Multi-day battery 5+ days of typical use on a single charge
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Water-resistant IP67 rated — rain, sweat, accidental splashes
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Bluetooth Low Energy Pairs with the ByStander app on iOS and Android
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9-axis motion sensing Accelerometer + gyroscope + magnetometer for accurate detection
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On-device processing Pattern recognition runs locally — no cloud lag, no privacy compromise
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Encrypted pairing End-to-end encryption between beacon and app
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Multiple form factors Pendant, bracelet, and clip-on variants planned
✓
Silent activation No lights, no sounds, no signal to an attacker
Common questions

Sentinel, answered.

When will Sentinel Beacon be available?
We're targeting a 2027 launch. Pre-orders for ByStander subscribers will open ahead of general availability. Add your email below to be notified the moment ordering opens.
How is this different from a smartwatch with SOS?
Smartwatches require a visible button press and an unlocked screen. Sentinel works in two modes: it triggers automatically for falls, struggles, and forced removal, and it offers a hidden silent trigger you can activate without an attacker noticing. It's also designed to look like jewelry, not a piece of consumer tech.
Do I need a ByStander subscription to use it?
Yes. Sentinel pairs with the ByStander app and uses your existing subscription for the advocate response, video streaming, and contact alerts. The hardware is a one-time purchase; the response service runs through your ByStander plan.
What if I get a false alarm?
Sentinel gives you a 15-second cancellation window with a discreet vibration before any incident is broadcast. If you confirm the cancel from your phone or by tapping the beacon in a specific pattern, no alert is sent.
Is there a monthly fee for the beacon itself?
No additional fee for the beacon hardware. Your ByStander subscription covers everything Sentinel triggers — advocate response, location, video, contacts — just as it does today from the app.
How is my data protected?
Sentinel processes motion data on-device. Nothing is transmitted unless an incident triggers, at which point the same encrypted ByStander incident pipeline takes over. We never sell or share your data, and recordings are deleted after 90 days unless you save them.
⚡ Pre-launch list

Be first in line for Sentinel.

Add your email and we'll let you know the moment pre-orders open in 2027. Subscribers on the pre-launch list get founding-pricing and priority shipping.

No spam. We'll only email you about the Sentinel launch.