[Labpacks] wanted to build a robot car controlled by his phone ... build a phone interface that will talk to your hardware over Bluetooth LE, USB, or Ethernet (including WiFi).

This Bluetooth-controlled car may seem too ambitious for a beginner project at first glance, but it's actually an easy build.

Arduino Bluetooth Controller by Ioannis Tzanellis Once you’ve graduated from the debugging stage to driving a remote-controlled car, tank, or robot, choose a controller with onscreen buttons. One such ...

So the driverless SEAT Leon Touring Car was a ... Saab being remotely controlled by a Nokia phone. Throttle, brakes and steering are all controlled via the phone through a Bluetooth connection.