27-06-2012, 12:34 PM
Cell Phone Controlled Land Rover Without Using Microcontroller
Cell Phone Controlled Land Rover Without Using Microcontroller.docx (Size: 231.25 KB / Downloads: 65)
The DTMF controlled land rover is the first choice of any person interested in robotics or electronics. After going through many blogs and sites, I found that none are able to present this simple project in a lucid manner to the beginners.
Here is the answer to many primary stage questions and troubleshoots related to this project.
A cell phone controlled land rover is the most unconventional project these days; this project remains a problem for who either have no or little knowledge of microcontrollers.
Well I have come up with a very conventional solution to this problem; one can replace the microcontroller with an equivalent logic circuit. The whole circuit gets compact in size also. However, as we all know everything has its own pros and cons, due over loaded logic lines there arise a problem of excessive current division however even this problem can be easily overcome by either using a current amplifier with the overloaded lines or by increasing the total current input to the whole circuit.
In the above circuit four ICs have been used:-
1) HT9170; DTMF tone decoder
2) L293D; comparator motor driver
3) 74HC04; high speed CMOS hex inverter (not gates)
4) 74HC86; high speed CMOS quad-XOR gates
The first IC (HT9170) decodes the DTMF tones to their respective BCD codes. The second IC (L293D) is a motor driver IC that is capable of handling the direction of motor easily according to the given logic inputs, this IC can handle up to 18V dc supply without any extra heat sink and 18V-30V with a heat sink. The other two ICs are logic gate ICs for the logic circuit between the decoder and the motor driver.
(NOTE: use HC=high speed CMOS ICs only for this circuit other IC would require extra hardware like pull up resistors, etc.)