10-08-2012, 11:55 AM
Cell phone operated Land Rover
Cell phone operated Land Rove1 explain.docx (Size: 69.6 KB / Downloads: 35)
Abstract:
you may have seen so many land rover projects on different websites or even on multyremotes.com as moon-walker and robo-vehicle. most probably they are remote controlled (either IR or RF) or they may be automatic guided vehicles (AGV). this is also remote controlled land rover but as a remote control one can use his cell phone. that means he can move the land rover by sending different commands from his cell phone. not only that, he can control it form any where in the world (of course where GSM / CDMA network is available).
This concept is taken from military application where such land rover works as Unmanned Guided vehicle (UGV) for spy operations, mine diffuser, bomb detector etc. in such application the movements of land rover can be controlled from very far remote and safe place (as there is practically no limitation on operating range)
Here I have develop very simple application in which the land rover moves forward, backward and takes left or right turn as per commands given from any cell phone but one can develop any interesting application over this platform like given above.
land rover circuit
I have divided complete circuit into three major blocks
1. DTMF decoder
2. Micro controller
3. DC motor driver
DTMF decoder: -
As shown in figure it is made up form readily available MT8870 chip that is widely used for DTMF based application. It receives DTMF tones and generates 4-bit digital output corresponding to received DTMF signal of digits 0 - 9 and other signals (like *, # etc) also. It receives input form cell phone to its pin no 2. It amplifies it through internal op-amp amplifier. If it receives valid DTMF tone, it will produce pulse output on StD (pin no 15). This is indicated by green LED connected as shown. The 4-bit digital output is latched on pins 11 - 14 and that is given to micro controller. The StD output is also given to interrupt pin of micro controller through transistor that will generate negative pulse every time when DTMF signal is received. This negative pulse will generate an interrupt. All the movements of robotic arm are controlled by cell phone digit switches 1 to 8. The 4 bit digital output corresponding to these switches form MT8870 are as given here
land rover C program
The program is very simple. It is written in embedded C language and compiled using KEIL (IDE). Initially in the main function, the ports are initializes as input or output. Then external interrupt 1 is enabled. Then the program waits in a continuous loop to for any input available from DTMF decoder. As interrupt arrives the program jumps to interrupt function and get the code. Then again it returns to main function and compares the code. As the match is found, it will send data 05h, 0Ah, 01h or 04h on port P2 to move rover forward, backward, left or right.