These are the additional hardware circuits that can be connected to
PMDK main board for added functionality.
Test Circuit for
Digital Output and Analog Input
This PCB is designed to plug in to Port C and the
last two channels of the Analog Inputs (Port A). The port C pins will
get connected to LEDs. A potentiometer will provide input to the
Seventh Analog Input (Port A, Bit 7)
This plug-in board provides four channels of
Op-amps. This board takes 5V supply from the main board and can be
plugged to the connector on the left bottom side.
H-bridge circuit for DC Motor Control
This Circuit can be plugged to I/O ports on the main
board to control the H-bridge inputs. Three LSBs are used for one
bridge and three MSBs for the second bridge, 4th and 5th bits are
unused. The supply to the H-bridge should be given through a 2pin
connector. The single sided PCB require two jumper wires to complete
This circuit has five LED-Phototransistor pairs. The LEDs can be
switched ON or OFF and the output of the phototransistor can be
measured using the analog inputs.
40 KHz Piezo
The piezo board is powered by the 9V DC input that
can be tapped from the main circuit. Two I/O pins go from the main
board to this circuit, one to send the signal to the transmitter piezo
and the other one to receive the amplified signal from the receiver.
This module can be programmed to measure distance to some object in
front of the tranceiver using the reflection of sound.
Output of four I/O pins are amplfied this board and
their output is provided in an open collector configuration. With
software this can be used to drive the 4 coils of a stepper motor, or
driving some relay coils. Power to this board is to be provided on a
separate two pin connector.
The ATmega16 micro-controller supports RS232
communication ports, through the RxD and TxD pins. On the circuit board
we have taken these lines to a 4 pin connector along with ground and 5V
supply. The Level Shifter module converts the -9V to +9V level signals
from the PC Serial ports to the 0 to 5V signals on the micro-controller
side. This can be plugged to the main board.