Proceedings of International Conference on Advances in Engineering and Technology
ISBN : 978 - 1505606395
DESIGN AND IMPLEMENTATION OF MOBILE OPERATED ROBOTIC CAR (WITHOUT USING MICRO-CONTROLLER) BY DTMF G.Sai Phaneendra kumar1 UG Student GMRIT, RAJAM
G.Divya2 UG Student GMRIT, RAJAM
G.Rohit3 UG Student GMRIT, RAJAM
Abstract- This paper explains the operation of a robotic car that is controlled by a mobile phone that makes a call to the mobile phone attached to the car. During the call, if any button on the keypad is pressed, a dial tone corresponding to the button pressed is heard at the other end of the call. This tone is called DTMF (dual-tone-multiple- frequency) which consists of two frequencies, one is high frequency and the other one is low frequency. The car receives this DTMF tone with the help of the another mobile phone connected to the car. The received tone is processed by adding an external network to DTMF decoder IC CM8870. The decoder decodes the DTMF tone into its equivalent binary digit and this binary number is sent to a driver IC L293D. Basing on the respective binary code word, this driver IC runs the motors which are connected externally. The mobile phone that makes a call to mobile phone attached to the car act as a remote. For that reason this paper does not require the construction of receiver and transmitter units and it is rather easy because we don’t use any micro controller.
INTRODUCTION Older day’s telephone communication is done manually by a person at the telephone switching centers. But present it is all done through Dual –tone multi-frequency (DTMF) signaling. This signaling is the one used in telecommunication signaling. The technique of DTMF used for telephone tone dialing is known to us by trademarked term Touch-Tone. It is called as MF4 in UK. As the number of persons using telephone communication increased day by day, it became a difficult task for manual switching, and then came DTMF through which a binary code word is generated for each dial tone basing on its respective frequencies and duration of the tone. Thus the address of the subscriber is well defined with a definite codeword and it became an easy task for the switching centers to connect the caller to its respective subscriber. Many of the home appliances can be controlled using this binary code word generated by DTMF .In this paper we control a robotic car basing on these code words. Although it has a wide range of control when compared with WIFI, BLUETOOTH modules, it is disadvantageous as it does not work when there is no signal in either of the mobile phones used.
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13 International Association of Engineering and Technology for Skill Development
Proceedings of International Conference on Advances in Engineering and Technology
ISBN : 978 - 1505606395
Frequencies corresponding to respective keypad tones
Internal working of DTMF IC: Internally this DTMF IC consists of three processing sections namely operational amplifier ,filter section ,detector section .DTMF signal is given as input for the inverting terminal of operational amplifier, for the non inverting terminal a reference voltage( nearly equal to Vdd/2) is given. The next processing section is filter section which consists of two sixth order switched capacitor band pass filters, the band widths of which correspond to low and high group frequencies. Each filter output is followed by single order switched capacitor filter section which smoothen the signal prior to limiting. Limiting is done by high gain comparators which are provided with some hysteresis to prevent detection of unwanted low-level signals. Logic swings are provided by the outputs of comparators for the respective frequencies. Following the filter section is a decoder section which employs digital counting techniques to analyze the frequencies of the incoming tones and verify with the standard DTMF frequencies. A complex averaging algorithm protects against tone simulation by extraneous signals such as voice, noise. We need a crystal oscillator externally to supply clock signal tuned for 3.8MHz frequency for the functioning of DTMF IC. Circuit description: Pin description: Pin description: 1st Pin(IN+):Non –inverting Op-amp 2nd pin(IN-):Inverting Op-amp 3rd Pin(GS):Gain select gives access to output of front end differential amplifier for connection of feedback resistor. 4th Pin(V ref):Reference voltage of VDD/2 is used to bias-inputs at mid-rail.
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14 International Association of Engineering and Technology for Skill Development
Proceedings of International Conference on Advances in Engineering and Technology
ISBN : 978 - 1505606395
5th Pin(Inhibit):Logic high inhibits the detection of tones representing characters A,B,C,D. This pin input is internally pulled down. 6th Pin(Power down):Active high powers down the device and inhibits the oscillator. This pin input is internally pulled down. 7thPin(OSC1):clock(input) 8th Pin(Osc2):clock(output).A 3.57MHz crystal connected between pins OSC1 and OSC2 completes the internal oscillator circuit. 9th Pin(Vss):Ground(input) 10th Pin(TOE):Three state output Enable(input).Logic high enables the output Q1-Q4.This pin is pulled up internally. 11th ,12th ,13th ,14th Pins are output data pins 15th Pin enables when the IC detects the valid DTMF tone 16th and 17th Pins helps in working of detector sections. 18th Pin(VDD):Positive power supply(input):+5V
Working: 9V battery is used as the supply for the circuit which should be connected . connect the universal headphone jack to mobile phone with facility of answering the call. Activate auto-
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15 International Association of Engineering and Technology for Skill Development
Proceedings of International Conference on Advances in Engineering and Technology
ISBN : 978 - 1505606395
answer mode in the mobile phone before connecting it to the circuit, and enable dial tones in the mobile phone that you use to make calls.
Robot is ready for operation wirelessly with GSM convenience .When we make a call to the mobile phone which is connected to the circuit. By pressing the dial tone, robot is moved in corresponding direction. It is made possible with the help of Dual Tone Multi Frequency receiver (IC CM8870), in which the sleeve connection of the robot cell phone is connected to the IC CM8870. The dial tone is received by the mobile phone connected to the robot and it is converted into binary code, and desired output is provided by the IC CM8870 to IC L293D. if for example,no.9 is pressed, it moves in the forward direction. Advantages: Used to control house hold appliances In industries and factories for remote sensing Using 3g technology we can spy a place Long distance remote sensing Can be implemented in avionics to switch auto pilot from ground station by sending a particular frequency • Addition of camera increases its usage • It is used as bomb with some modifications • • • • •
Disadvantages: •
Call charges
•
Not at all useful if we do not have network.
•
Head phones which are damaged frequently. CONCLUSION
In this paper we clearly illustrate the design and implementation of a mobile operated robotic car using DTMF. It is wireless operated one as we are using mobile phones for transmission and
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16 International Association of Engineering and Technology for Skill Development
Proceedings of International Conference on Advances in Engineering and Technology
ISBN : 978 - 1505606395
reception of DTMF tone, and thus it is advantageous. In future scope by adding external networks we can further control many number of home appliances also. REFERENCES [1]. Ladwa, T.M.; Ladwa, S.M.; Kaarthik, R.S.; Dhara, A.R.; Dalei, N., "Control of remote domestic system using DTMF," Instrumentation, Communications, Information Technology, and Biomedical Engineering (ICICI-BME), 2009 International Conference on , vol., no., pp.1,6, 23-25 Nov. 2009 doi: 10.1109/ICICI-BME.2009.5417279 [2]. Siegmund M. Redl, Matthias K. Weber, Malcolm W. Oilphant, GSM and Personal Communications Handbook, Artech House Boston, London. [3]. “DTMF Tester”, Electronics For You’ Magazine, Online Edition (June 2013). [4]. Edwin Wise, Robotics Demystified (Mc-Graw Hill, 2013) [5].M-8870 DTMF Receiver, Information available www.datasheetcatalog.org/datasheet/clare/M-8870-01SMTR.pdf
at
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link,
[6]. Awab Fakih, Jovita Serrao, Cell Phone Operated Robotic Car. International Journal of Scientific & Engineering Research, ISSN 2229-5518.
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