A simple app that regularly publishes to a configurable MQTT topic whenever connected to a given WiFi network or in proximity to a Bluetooth beacon. This can be used to integrate the presence of your phone in home automation.
Several networks and beacons can be configured at once and the message to be sent can be configured for each of them.
If your MQTT server is available on the internet, you can also choose to send an 'offline' message whenever you are not connected to any of the configured WiFi networks and not in range of any configured beacon.
As an additional feature, you can send the battery level of your device whenever a condition is met, so that you can recharge it before it turns off.
The app uses the built-in Android alarm manager, so notifications are sent even if the phone is in stand-by.
The app uses the default Android CA trust store for checking the server certificate validity. You can simply add your certificate via:
Settings → Security → Install from SD cardSettings → Security & location → Encryption & credentials → Install from SD cardThe Android keychain will only allow you to import a PKCS#12 keystore. If you have created a client certificate along the lines of https://mosquitto.org/man/mosquitto-tls-7.html, you will need to combine the certificate and key file together like this:
openssl pkcs12 -inkey client.key -in client.crt -export -out client.pfxIf you do not need your client certificate to be signed by a root certificate, because you plan to add it directly to the trusted certificates of your MQTT broker, you can also use the KeyStore Explorer to generate your client certificate:
Create a new KeyStore → choose PKCS #12Tools → Generate Key Pair → choose one of Android's
supported algorithms
→ configure properties of the public certificate → set a password for the private keyFile → Save → use the same password as above for the keystoreMake sure your PKCS#12 keystore file has the .pfx extension, otherwise Android will not recognize it.
