I’ve been researching indoor location technoglogy which has lead me to looking more closely at the cost and effort of implementing Bluetooth Beacons, like Apple’s iBeacon or Google’s now unsupported Eddystone protocol. That led me to Bluetooth “Trackers,” “Tags” or “Key Finders.” There are also BLE sensor tags and fitness trackers. These are my barely edited notes.
Cheap Modules
There are a huge number of cheap Bluetooth ≥4 modules on eBay and AliExpress. Some are bare modules that include a Bluetooth SoC, an antenna, and supporting circuitry intended for integration into a larger device. Others are, more or less, finished devices. The have cases, and battery holders or connectors for an external USB power supply. They also often have demo firmware and apps.
Tracker devices are available for less than $2, with shipping, but they have unknown or poorly documented SoCs and repurposing them may be difficult or impossible.
For more flexible modules with well documented and supported SoCs from Nordic and TI, prices start at $4 for a basic coin cell powered device with Bluetooth 4LE support and go upward for more recent chips with support for later Bluetooth version and/or cases for more durable installation. Bare modules for incorporation into devices are available for less than $2.
- Shenzen Wellicorp: fixed and portable beacons with waterproof housings using nRF51, nRF52 and TI CC2541 SoCs.
- Bejing Aprilbrother: DA14580, nRF52 & TI based fixed and portable beacons and sensors.
- Radioland Technologies TI nRF and Dialog based beacons. Available from 3rd party sellers on AliExpress, like Shenzhen Duoweisi Tech
- Holyiot Sensors and beacons based on nRF51 & nrRF51. Also
- Minew sensors, beacons and electronic shelf lables based on nRF51 & nRF52 and, TI BLE SoCs. Their beacons were used for Google’s first public Eddystone demo. They sell BLE 5 capable beacons for $10 + shipping, with a three unit minimum order.
Bluetooth Profiles of Interest
- Proximity
- Find Me
Common Bluetooth SoCs
Their are a variety of manufacturers of Bluetooth SoC, but Texas Instruments and Nordic Semiconductor seem the most common.
| Mfg | Model | Intro | Notable | MCU |
| Texas Instruments | CC2540 | Oct 2010 | BLE v4, v5, USB | 8051 |
| CC2541 | Jan 2012 | BLE v4, v5 | 8051 | |
| CC2640 | Feb 2015 | BLE v4.2, v5 | Ctx-M3 | |
| CC2640R2F | Dec 2016 | BLE v4.2, v5 | Ctx-M3 | |
| Nordic Semiconductor | NRF51822 | 2014? | BLE v4.1-4.2 | Ctx-M0 |
| NRF52810 | BLE 5 | Ctx-M4 | ||
| NRF52811 | BLE 5.1 + direction finding | Ctx-M4 | ||
| NRF52832 | BLE 5 | Ctx-M4F | ||
| Dialog | DA14580 | |||
Texas Instruments
TI has updated SDKs for some of its BLE v4 ICs that are v5 certified for the subset of v5 features that the IC supported in v4.
TI’s BLE SoC all support a variety of peripherals relevant to sensor node applications. Some have integrated switching power supplies.
Nordic Semiconductor
Like TI, Nordics SoC’s support a variety of peripherals relevant to sensor node applications, and some have buck converters.
Nordic has a proprietary protocol called ANT which can also run on some of their SoCs at the same time as BLE.
Nordic’s nRF5 SDK includes sample applications for iBeacons, and proximity tags.
Others
- Dialog? DA14580
Elsewhere
- Teardown of three different Bluetooth Low Energy Tracking tags (2016)
- Hacking a $3, dollar store, Bluetooth camera shutter (2016) pt 1, pt 2, pt 3
- Teardown of a Chipolo Plus nRF51822 tracking tag (2016)
- Lenze ST17H2X
- Teardown of a cheap eBay tracking tag based on a low cost ST17H25 Chinese SoC (2015)
- Yet another cheap BLE tracker tag teardown (2016) using a similar chip as the above — mis-indentified as a TLSR8263 from Telelink Semiconductor
- ST17H26 product listing on LCSC $0.9307 for quantity 1! (datasheet)
ToDo
Or not, but I’m at least noting them
- Battery life estimates
- NFC for proximity based pairing
- Applications for UWB?
- Sensor/fitness tags
- “Finder” app ecosystems
- What is WeChat Shake?
- Is there any standardization of a protocol for configuring beacons?
- Bt 5 Advertising Enhancements — Use of more channels for advertising packets, reducing interference. Extended advertising lets advertisements use a larger payload (in another channel), allowing more info to be conveyed in beacon applications.