Android/iOS: If you want to control a Raspberry Pi or Arduino connected device from your phone, you’d usually need to know at least some programming. Blynk is an app that makes it easier to ...

– Download the Blynk app on your smartphone and create an account. – Create a new project, select from the list your hardware (Raspberry Pi 3). – Select connection type (Wifi,Bluetooth…).

While the Raspberry Pi has very good support for an I2C bus, a lot of very cool chips – including the in system programmer for just about every ATtiny and ATmega microcontroller – use an SPI bus.