(4) (2) (3) (1)
MPEG
is consists of 4 major modules: (1) Goal module, (2) SWAG module (3) Shooting module
and (4) Buzzer, Potentiometer, and LEDs. Additionally, it has a control panel
and a ball-extracting part.
Coin sensor circuit uses an Op-amp
and a comparator. A trans-resistive circuit is used to generate the current
when IR signal is received. The output of the trans-resistive circuit is
connected to LM324 in order to amplify the signal. The output of the amplifier
is connected to a Schmitt trigger implemented with LM339 in order to create a
clean, noise free digital signal. The output of the Schmitt trigger is tied to
the input of the pin AD3 of a 9S12C32 to interface.
Backup Calculations
V+ of LM324 was connected to the
potentiometer. The voltage of the potentiometer was 3V.
The following Schmitt trigger (Rpullup
= 3.3 K§Ù, R4 = 10 K§Ù, R5 = 100 K§Ù, R6 = 2.2 K§Ù, and R7 = 3.3 K§Ù) where
is used.
Since the amplifier and the Schmitt
trigger are inverting ones, the output of the circuit is low when there is a
goal and high otherwise.