An iTag is cheap (< 2 euro) Bluetooth Low Energy (BLE) device equipped with a button and piezzo buzzer. This CLI tool publishes iTag button press notifications to a MQTT queue.
Requirements:
- gcc
- GattLib (
lgattlib) - GLib (
lglib-2.0) - Paho MQTT C Client (
lpaho-mqtt3c)
Build:
$ make
Note: since GattLib is a dependency, you can only build on Linux.
./button <MAC ADDR OF BUTTON>
There are a variety of types of iTags, with different branding. iTags I have been working with were branded as Dehyaton.
Although iTags seem very attractive to use as a smart button in home automation applications, especially because of their low price, there are some big caveats.
- Connection behaviour is erratic. And, it is often difficult to reconnect after disconnection.
- Range is limited.
- No difference in notification data between single, long and double click.
- Beeping on button press and connection loss is annoying. There is no known way of disabling these beeps that work for all devices. Although there seem to be iTag versions around which support turning off the beeping. If device supports disabling beeping, a "Link loss service" (UUID 0x1803) is supposed to be discoverable on device (on mine there is no such service).
- Device switches off after some time, even when still connected and even when there has been regular button press activity. When device is off, you need to turn it on again (long press on button) and reconnect.
These devices are perfect though for experimenting with the Bluetooth Low Energy and GATT protocol stacks.
And, to be fair, I should mention that iTags are not designed to be used as a smart button, their intended use is as a tracking device, to help you find your keys for example. Hence the beeping on connection loss.