The MTS8870D is a complete DTMF 
receiver consisting of digital decoder. The 
decoder uses digital counting techniques to 
detect and decode all 16 DTMF tone-pairs into a 
4-bit code. The output 4-bit code is given as 
input to the microcontroller. 
I.A.3. Microcontroller (ATM89C51) 
Microcontroller is the heart of the robot. 
Microcontroller is the main controlling unit of 
the robot. We are using microcontroller 
At89C51. The At89C51 is a low-power, high- 
performance CMOS 8-bit microcomputer with 
4K bytes of Flash programmable and erasable 
read only memory (PEROM). 
[.A.4. Drive Control Logic And Peripheral 
Control Logic 
Drive control logic consists of relay boards. 
DC motors are connected to these relay boards. 
A relay is an on/off switch that you can control 
electronically. 
I. A.5. Wireless Camera 
We are using Wireless camera Xcam2 in our 
project. It consists of a Built-in 2.4 GHz Video 
Sender. 
I. B. Experimental 
The main controlling technique using DTMF 
can be explained as follow: 
Integrated DTMF Receiver 
I. B. 1. Features: It has low power consumption, 
adjustable guard time, inhibit mode. These 
are the features, which we have used. 
[. B. 2. Applications : It is widely used in 
Receiver system for British Telecom, Paging 
systems, Repeater systems/mobile radio, 
Credit card systems, Remote control, 
Personal computers, Telephone answering 
machine, etc. 
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B5. Istanbul 2004 
II. DESCRIPTION 
The MT8870D/MT8870D-1 is a complete 
DTMEF receiver integrating both the band split 
filter and digital decoder functions. The filter 
section uses switched capacitor techniques for 
high and low group filters; the decoder uses 
digital counting techniques to detect and decode 
all 16 DTMF tone pairs into a 4-bit code. 
External component count is minimized by on 
chip provision of a differential input amplifier, 
clock oscillator and latched three-state bus 
interface. 
II. A. Functional Description 
The MT$8870D/MT8870D-1 monolithic 
DTMF receiver offers small size, low power 
consumption and high performance. Its 
architecture consists of a band split filter 
section, which separates the high and low group 
tones, followed by a digital counting section 
which verifies the frequency and duration of the 
received tones before passing the corresponding 
code to the output bus. 
II. A. 1. Filter Section : Separation of the low- 
group and high group tones is achieved by 
applying the DTMF signal to the inputs of 
two sixth-order switched capacitor band pass 
filters, the bandwidths of which correspond 
to the low and high group frequencies. The 
filter section also incorporates notches at 
350 and 440 Hz for exceptional dial tone 
rejection. 
II. A. 2. Decoder Section : Following the filter 
section is a decoder employing digital 
counting techniques to determine the 
frequencies of the incoming tones and to 
verify that they correspond to standard 
DTMF frequencies. A complex averaging 
algorithm protects against tone simulation 
by extraneous signals such as voice while 
providing tolerance to small frequency 
deviations and variations. 
Steering Circuit: Before registration of à 
decoded tone pair, the receiver checks for a