Line Follower

This Robot use two motors control  rear wheels and the single front wheel is free. It has 4-infrared sensors on the bottom for detect black tracking tape, when the sensors detected black color, output of  comparator, LM324 is low logic and the other the output is high.

Microcontrollor AT89C2051 and H-Bridge driver L293D were used  to control direction and speed of motor.

Circuit Robot

Circuit diagram of Infrared sensor

position of sensors

Software
Software for write to AT89C2051 is robot1.hex ,which was written by C-language ,the  source code is robot1.ccompiled by using MC51 in TINY model with my start up code robot.asm .
MPEG files
Sample of competition between 2051 and 68HC11.

movie1.mpg (1,303kB)

movie2.mpg (373kB)

Source : www.kmitl.ac.th
Contact Owner : plermjai@loxinfo.co.th

Rangkaian led 7 segment

Rangkaian Led 7-Segment Interface Circuit

The circuit uses a serial-in-parallel out shift register, 74HC595 for receiving serial data from uController board. See example of U5 in the schematic, SER is for data input, SRCLK is shift clock and RCLK is Latch clock. Each data bit is shifted into the register on rising edge of the shift clock. When all data bits are shifted into the 8-bit register, the rising edge of RCLK will clock the data to be latched at each output bit, i.e. QA – QH.
The Big LED is made from cheap dot LED. Each segment has five dot LED connected in series with a limiting resistor tied to +12V. The logic high at the input of ULN2003 makes the output active low, thus sinks the LED current into the chip. The driver has 7-bit for segment a, b, c, d, e, f, and g. Q1 is for optional point display.
Multiple digits can easily be made by connecting the QH to the next digit serial input bit, see the circuit below. Please note that, the shift clock and latch signal are tied to every 74HC595.