Tag Archives: Bluetooth

Hoard of the rings: extracting data from Colmi BLE annular activity trackers

I’m not especially a fan of the ‘quantified self’, the notion that I should continuously record massive amounts of data about my daily life and physiological state. But I am keen on Bluetooth LE communications, and this reason, not the former, is why I acquired a Colmi R02 “smart ring” from the PRC.

Colmi R02 smart ring. Image © 2025 Tony Smith

And all for a mere £6.24 including postage and packing. Barg!

The ring contains a tiny microcontroller and BLE radio, plus an accelerometer for step counting, a blood oxygen reader and a heartbeat sensor. It’s powered by a battery recharged using a tiny magnetic jack that you plug into any USB adaptor. Wee it may be, but the 17mAh battery will give you around five days’ usage on a full charge. From its size, the MCU looks like it’s the BlueMicro RF03, but the precise type is not stated in the ring’s specs.

Continue reading →

How to use a mouse with an iPad

You don’t need a mouse when you’re using an iPad, right? That’s Apple’s view, but it’s not mine. If you use an iPad as a small, very portable laptop — maybe you have the iPad’s Smart Keyboard add-on — then you don’t necessarily want to be moving your hand up to the screen every time you want to point and click.

0A8EE407-2BC0-4846-95C9-15121750722B

Continue reading →

Raspberry Pi Knowledgebase added

I’ve created a page containing simple sets of instructions for some key — and not so widely used — Raspberry Pi setup tasks. The goal is to have a single source that I (and anyone else) can check when they need to look up what they should do to perform a specific action: setting up Node.js, for example, or using Dropbox.

You can find the Knowledgebase here.

How to build your own Apple iBeacon… with a Raspberry Pi

US department store Macy’s recently said it is implementing iPhone-based tracking tech the better to encourage browsing punters to buy. Of course, Macy has chosen to pitch this as an Apple technology – figuring, presumably, iPhone owners are more receptive to inducements delivered through technology and have more cash to splash than Android fans.

A Pi's UART pins, connected
Can this operate as an Apple iBeacon? Yes it can
Continue reading →