radio frequency based wireless robot using 8051 microcontroller
BASIC REQUIREMENT:
DESCRIPTION OF EACH IC'S
AT89C51
AT89C51 is an 8-bit controller and belongs to Atmel's family. ATMEL 89C51 has 4KB of Flash programmable and erasable read only memory (PEROM) and 128 bytes of RAM. It can be erased and program to a maximum of 1000 times.
BASIC REQUIREMENT:
- AT89C51 microcontroller IC
- L293D motor driving IC
- HT12E an encoder IC
- HT12D a decoder IC
- 2 dc motors
- powersupply 5 volts
- male and female connectors
- led's and resistors
- IDE- Keil u vision 4
- SIMULATOR: proteus
DESCRIPTION OF EACH IC'S
AT89C51
In 40 pin AT89C51, there are four ports designated as P1, P2, P3 and P0. All these ports are 8-bit bi-directional ports, i.e., they can be used as both input and output ports. Except P0 which needs external pull-ups, rest of the ports have internal pull-ups. When 1s are written to these port pins, they are pulled high by the internal pull-ups and can be used as inputs. These ports are also bit addressable and so their bits can also be accessed individually.
Port P0 and P2 are also used to provide low byte and high byte addresses, respectively, when connected to an external memory. Port 3 has multiplexed pins for special functions like serial communication hardware interrupts, timer inputs and read/write operation from external memory. AT89C51 has an inbuilt UART for serial communication. It can be programmed to operate at different baud rates. Including two timers & hardware interrupts, it has a total of six interrupts.
L293D
Here is the pin diagram of L293D ic and connection to the motors is shown.
HT12E
It has been shown here the ht12e ic along with its connections with antenna and switches for providing inputs
Simply put, HT12E converts the parallel inputs into serial output. It encodes the 12 bit parallel data into serial for transmission through an RF transmitter. These 12 bits are divided into 8 address bits and 4 data bits.
HT12E has a transmission enable pin which is active low. When a trigger signal is received on TE pin, the programmed addresses/data are transmitted together with the header bits via an RF or an infrared transmission medium. HT12E begins a 4-word transmission cycle upon receipt of a transmission enable. This cycle is repeated as long as TE is kept low. As soon as TE returns to high, the encoder output completes its final cycle and then stops.
HT12D
the connectiion of decoder ic is shown here with microcontroller.
in simple terms, HT12D converts the serial input into parallel outputs. It decodes the serial addresses and data received by, say, an RF receiver, into parallel data and sends them to output data pins. The serial input data is compared with the local addresses three times continuously. The input data code is decoded when no error or unmatched codes are found. A valid transmission in indicated by a high signal at VT pin.
HT12D is capable of decoding 12 bits, of which 8 are address bits and 4 are data bits. The data on 4 bit latch type output pins remain unchanged until new is received.
RF RECEIVING AND TRANSMITTING ANTENNA
the onnections of rf receiving and transmitting antennas has been already shown in above figures.
PROGRAM
the programming has been done in assembly language which is a machine dependent language.
main program :
org 00h
mov p1,#0xff
mov p2,#00h
main:
jnb p1.0,forward
jnb p1.1,backward
jnb p1.2,rtmov
jnb p1.3,lftmov
sjmp stop
stop:
clr p2.7
clr p2.4
clr p2.6
clr p2.5
sjmp main
forward:
setb p2.7
setb p2.5
clr p2.4
clr p2.6
sjmp main
backward :
setb p2.6
clr p2.5
setb p2.4
clr p2.7
sjmp main
rtmov:
setb p2.7
clr p2.4
clr p2.6
clr p2.5
sjmp main
lftmov:
clr p2.7
setb p2.5
clr p2.6
clr p2.4
sjmp main
end
FINAL DIAGRAM:
