Building your own mobile robot is becoming easier and easier, thanks to excellent ready-to-use robotic platforms. A good example of such platform is the Adafruit Mini Robot Chassis kit, which comes with a nice robot chassis, two servo motors with wheels and a support-wheel. This makes it the perfect base for all your mobile robot projects.
On the other hand, you now can buy powerful & cheap microcontrollers like the ESP8266 WiFi chip, which is not only easy to use but also comes with onboard WiFi connectivity. This is just the perfect chip to control robots remotely from your computer or mobile device.
All the code is provided, clearly written and commented:
Make a robot friend with Adafruit’s CRICKIT – A Creative Robotics & Interactive Construction Kit. It’s an add-on to our popular Circuit Playground Express, FEATHER and other platforms to make and program robots with CircuitPython, MakeCode, and Arduino. Start controlling motors, servos, solenoids. You also get signal pins, capacitive touch sensors, a NeoPixel driver and amplified speaker output. It complements & extends your boards so you can still use all the goodies on the microcontroller, now you have a robotics playground as well.