Awab Fakih, Jovita Serrao
Abstract — Conventionally, wireless-controlled robots use RF circuits, which have the drawbacks of limited working range, limited frequency range and limited control. Use of a mobile phone for robotic control can overcome these limitations. It provides the advantages of robust control, working range as large as the coverage area of the service provider, no interference with other controllers and up to twelve controls. Alth ough the appearance and capabilities of robots vary vastly, all robots share the features of a mechanical, movable structure under some form of contr ol. The control of robot involves three distinct phase namely perception, processing and action. Generally, the preceptors are sensors mounted on the robot, processing is done by the on-board microcontroller or processor, and the task (action) is performed using motors or with some other actuators.
Index Terms— Dual-Tone Multi-Frequency (DTMF), radio control, remote control vehicle, Touch-Tone, Perception, Flash Override —————————— ————————— UK as MF4. Other multi-frequency systems are used for signaling internal to the telephone network .
Radio control (often abbreviated to R/C or simply RC) is the use of radio signals to remotely control device. The term is used frequently to refer to the control of model vehicles from a handheld radio transmitter. Industrial, military, and scientific research organizations make use of radio-controlled vehicles as well. A remote control vehicle (RCV) is defined as any mobile device that is controlled by a means that does not restrict its motion with an origin external to the device. This is often a radio control device, cable between control and vehicle, or an infrared controller. A RCV is always controlled by a human and takes no positive action autonomously. One of the key technologies which underpin this field is that of remote vehicle control. It is vital that a vehicle should be capable of proceeding accurately to a target area maneuvering within that area to fulfill its mission and returning equally accurately and safely to base. This project includes a robotic car consisting of a cell phone, DTMF decoder and microcontroller. The transmitter is a handheld mobile phone. The technology used is explained in section II, the circuit design, construction and working are in section III and IV. The applications and future scope of the project is explained in the further sections.
2.2 Telephone Keypad
The contemporary keypad is laid out in a 3×4grid, although the original DTMF keypad had an additional column for four nowdefunct menu selector keys. When used to dial a telephone number, pressing a single key will produce a pitch consisting of two simultaneous pure tone sinusoidal frequencies. The row in which the key appears determines the low frequency, and the column determines the high frequency .
Fig. 2.1: DTMF system assignments For example, pressing the '1' key will result in a sound composed of both a 697 and a 1209 hertz (Hz) tone as shown in Fig. 2.1. The original keypads had levers inside, so each button activated two contacts. The multiple tones are the reason for calling the system multi frequency. These tones are then decoded by the switching center to determine which key was pressed .
2.3 Tones #, *, A, B, C, and D
The engineers had envisioned phones being used to access computers, and surveyed a number of companies to see what they would need for this role. This led to the addition of the number sign (#, sometimes called 'octothorpe' in this context) and asterisk or "star" (*) keys as well as a group of keys for menu selection: A, B, C and D. In the end, the lettered keys were dropped from most phones, and it was many years before these keys became widely used for vertical service codes such as *67 in the United States and Canada to suppress caller ID. The U.S. military also used the letters, relabeled, in...