Robot cars made using RF technology have limited range of operation. But in cell phone operated robot car, range is as large as the coverage area of the service provider.

In this project two cell phones are used. One cell phone is used to make a call to other cell phone which is connected in receiver. The robot car is controlled by cell phone using DTMF technology. DTMF is an acronym for Dual Tone Multi Frequency. When we press any key of our cell phone (from 1 to #) it generates a frequency. This frequency or you can say a specific tone is transmitted to other cell phone which is connected to DTMF decoder circuit. The DTMF decoder circuit generates a code corresponding to the received frequency. This code act as input or command for microcontroller and it follows that command and perform the programmed operation.

We can also add camera and some sensors to it like obstacle sensor etc.