They used the webaudio API to send serial data to a remote Arduino. The hack uses a FET, a capacitor, and a few resistors. They didn’t quite build a real modem with the audio.

This Arduino MIDI sequencer has no shortage of ways to display loop info. The screen above is a touch-sensitive interface that acts as the user input. But if this screen is not visible, you can sti… ...

Using an IoT SIM that works on cellular networks in over 100 countries, the Electron's basic data plan starts at $2.99 per month for 1 megabyte of data and 99 cents for each additional megabyte.

Arduino devices have had the option of a GSM linkup for awhile, but getting that cellular link to truly strut its stuff hasn't always been easy, even for those of us who'd be inclined to program ...