DTMF Audio Communication for NAO Robots.

We propose an alternative to Wi-Fi for robotic communication, as its increased use in a competition environment has lead to highly overlapping and interfering networks. This interference often causes unreliable transmission of data, which affects teams’ ability to coordinate complex behaviors. Our method uses fixed length Dual Tone Multi Frequency (DTMF) messages and uses a basic packet structure designed to reduce data corruption as a result of noise. We conducted twelve different experiments varying the distance between robots and message format, as well as whether the robots are walking or sitting silently. Methods for scheduling messages to avoid crosstalk were also developed and tested. The results show that while this method appears to be sensitive to motor noise, room reverberation and multipath effects, it has very low data corruption rates, which makes it suitable for use in some applications.