Specifications

CONSTRUCTION
S.C. DWIVEDI
MULTI-EFFECT CHASER LIGHTS
USING 8051 MICROCONTROLLER
T
he 8051 microcontroller, first de-
veloped by Intel, finds many ap-
plications in small development
systems such as speed control of DC
motors, timers, process-control applica-
tions, and tem-
perature con-
trollers. One
of its simple
applications as
multi-effect
chaser lights is
described in
this project.
Here the
microcontroller
8051 controls
the switching
sequence of
eight triacs
(TR1 through
TR8) via the
buffer transis-
tors T1 through
T8, as shown
in the sche-
matic diagram
of Fig. 1. Each
triac, in turn,
may be used to
control a series
of bulbs (with a
total voltage
drop of 230V
AC and the cur-
rent drawn
through BT136
triacs not ex-
ceeding 4 amp).
Features
of 8051 micro-
controller. The
heart of the cir-
cuit is the 8051
microcontroller.
Some of the im-
portant fea-
tures of the
controller are as
follows:
— 8-bit CPU with register A (accu-
mulator) and register B.
— 16-bit program counter (PC).
— 16-bit data pointer (DPTR).
— 8-bit program status word (PSW).
— 8-bit stack pointer.
— 128 bytes of internal RAM.
— No ROM for 8031, 4k ROM for
8051, and 4k EPROM for 8751.
— Two external and three internal
interrupt sources.
— Four programmable input-output
ports/registers.
One of the important parts of the
8051 CPU is its oscillator section. The
oscillator section is present on the chip
itself, only quartz crystal has to be con-
ADITYA U. RANE
Fig. 1: Schematic diagram of multi-effect chaser lights
181