Presumably, the core phone module will have regulatory acceptance ... Of course, we’ve seen GSM and cell phone shields for Arduino before. Difficult to imagine sticking those in a dog collar ...

He decided to go with the low-cost SIM800L GSM modem, but as it only works on 2G networks, provisions have been made in the board design to swap it out for a more modern module should you desire.

You'll need the sensor module R305 to read your fingerprint ... There are hundreds of different Arduino builds on the ...