★ Recommended
KKM F1 / B2
SOS Panic Button · BeaconZone (London)
ChipsetNordic nRF52
BLE Version5.0
Open SDKYes — GitHub
ProtocoliBeacon / Eddystone
Onboard buzzerYes (dB unconfirmed)
IP RatingIP67
ChargingMagnetic (not USB-C)
White-labelYes — ODM available
UK Price£27 via BeaconZone
Dev RiskLow–Medium
B2 variant adds audible confirmation beep on press — better UX. Confirm 130dB spec with KKM directly: sales@kkmcn.com
Clean Protocol
Flic 2 / Flic Duo
Smart Button · Amazon.co.uk / flic.io
ChipsetNordic nRF52
BLE Version5.0 (50m range)
Open SDKYes — full byte-level spec
ProtocolFully published GitHub
Onboard buzzerNo — phone provides alarm
IP RatingNot specified
ChargingCoin cell (CR2032)
White-labelNo — branded Flic only
UK Price£23–27 Amazon.co.uk
Dev RiskLowest of all options
Flic Duo (Jan 2025) adds fall detection + dual button. Best choice if cleanest protocol spec is the priority. No production ODM path.
Alternative
Minew MWB02
Wearable Panic Button · BeaconZone
ChipsetNordic nRF52
BLE Version6.0
Open SDKYes — docs.minew.com
ProtocoliBeacon / Eddystone
Onboard buzzerHaptic vibration only
IP RatingIP67
ChargingMagnetic (260mAh)
White-labelYes — OEM/ODM
UK Price£41.58 BeaconZone
Dev RiskLow–Medium
Wristband form factor — not keychain. Accelerometer supports fall detection (useful future feature). Higher cost than KKM.
BLE
Bluetooth Low Energy. A version of Bluetooth designed for small devices that need to run on a small battery for months or years. Uses very little power compared to classic Bluetooth. Almost all modern personal safety devices and fitness trackers use BLE.
Nordic nRF52
The most popular BLE chip family in IoT and wearables — made by Nordic Semiconductor (Norway). Used by KKM, Flic, Minew, and many others. It's the "gold standard" because it has excellent documentation, a large developer community, and long battery life. When you see nRF52 in a spec, it means the device will be easy to develop against.
iBeacon
Apple's BLE advertising standard, released 2013. A device broadcasting as an iBeacon sends a regular Bluetooth signal containing a UUID (unique ID), Major number, and Minor number — like a digital name badge. Any phone in range can detect it. The KKM devices use this as their primary broadcast method, making them compatible with both iOS and Android apps without any pairing required.
Eddystone
Google's open BLE beacon format, equivalent to iBeacon. Eddystone-UID broadcasts a 16-byte identifier. Eddystone-URL can broadcast a web address directly. KKM devices support both iBeacon and Eddystone, giving maximum app compatibility. Open standard — no licence required.
GATT
Generic Attribute Profile. The framework BLE uses for two devices to have a conversation (not just broadcast). A GATT connection lets your app read data from the device and write commands to it — e.g., change the LED colour or tell it to beep. More capable than iBeacon/Eddystone broadcasting but requires the device to be "connected" rather than just "advertising".
SDK
Software Development Kit. A package of code and tools that a manufacturer provides so developers can build apps for their hardware without starting from scratch. An open SDK on GitHub means any developer can download it for free, inspect it, and use it. A closed or paid SDK (like Tuya's) means you must buy a licence before you can build anything.
ODM
Original Design Manufacturer. A factory that will take their existing proven hardware design and rebrand it with your logo, colours, and packaging. KKM offer ODM on their nRF52 platform — meaning Aaron could have a device that looks and feels like his own product but runs on proven, already-certified hardware. Lower risk and faster to market than designing a device from scratch.
MOQ
Minimum Order Quantity. The smallest number of units a manufacturer will produce in one run. BeaconZone sells KKM devices with MOQ of 1 (great for POC). Direct from KKM, standard products have no MOQ for small orders. A custom ODM product (your own branding, custom design) typically requires 500–1,000 units minimum as the factory needs to cover tooling and setup costs.
IP67
Ingress Protection rating. The 6 means fully dustproof. The 7 means it can be submerged in up to 1 metre of water for 30 minutes. For a personal safety alarm that might be used by runners, in rain, or in stressful situations, IP67 is the minimum you'd want. IP65 (water-resistant, not submersible) is acceptable; anything lower is a product quality concern.
POC / MVP
Proof of Concept / Minimum Viable Product. POC = a working demo that proves the core idea (button triggers app, app sends alert). MVP = the simplest version you'd put in front of real users to test. For Aaron's project: POC uses off-the-shelf KKM hardware + app. MVP adds polish, onboarding, and a small beta group. Full launch comes after MVP validation.
CE / FCC
Mandatory safety certifications. CE = required to sell in the UK and EU. FCC = required to sell in the USA. These cover electromagnetic compatibility and radio frequency compliance. KKM's existing products already hold CE and FCC — if Aaron uses KKM ODM hardware, he inherits these certifications rather than having to commission new testing (which costs £5k–£30k and takes months).
Tuya Cloud Lock
Tuya is a Chinese IoT platform. Most cheap AliExpress smart devices run Tuya firmware and route all their data through Tuya's servers in China. Building a custom app against a Tuya device requires their commercial SDK ($5,000/yr), a per-device licence fee on every unit sold, and accepting that all device data passes through Tuya's infrastructure — which is a GDPR risk for UK/EU customers and a commercial risk (Tuya controls your product's connectivity).