You will want to use a flat surface for the robot and a quiet room without several of your friends also using sound to control their robots (unless you pick different control frequencies). I used both wood and low-pile carpet with good results. The servos have good torque to move. The robot is sensitive to bumps as a two wheeled robot turns wil slight changes in differential between wheels.
Put the robot on a good surface, plug in a charged LiPo battery and ensure the slide switch on the Circuit Playground board is on the "+" position. You can test if things are working well by holding the robot and pressing the right pushbutton on Circuit Playground. It should run forward. Pressing the left button stops it. If you pick the robot up and want the wheels to stop, press the left pushbutton and then turn the slide switch to "-". The slide switch is not a power switch though, when you want to have the robot off for a period of time, unplug the battery.
How close the control unit must be to the robot depends on a number of factors:
- Volume of the speaker (amplified or unamplified)
- If the microphone is facing the tone generator. If it is off center, the amount of sound energy getting to the microphone will be less.
- Ambient noise from other sources.
You can consider a cylinder or funnel on the front to focus sound to the microphone (where the ear symbol is on Circuit Playground).