booksbybibin

[yogi]

HAND DRIER
You have seen in hand driers in good hotels. The aim of the hand drier is
to dry your hand after you wash your hand. There are two types of hand
driers, one is manually operated through a switch, other is one automatic.
Here we are going for automatic one. Hand drier consist of a motor for
producing heat air. Hand drier produces dry air when your hand is below
a specified height of the hand drier. You can hear the switching sound of
the relay when you put your hand under the hand drier. So now you try to
make the circuit. The possible configurations are IR LED+photo diode(or
photo transistor)+relay+motor and 38KHz modulated
IR+TSOP+relay+motor. Using photo diode you can get up to 7cm. I think
photo diode is enough for this purpose than going for TSOP.


Here the height of the hand below the drier is decided by the voltage
reference. When hand is not there, there is no reflection. So the current
through the photo diode is low making the transistor OFF and when you
bring hand below, there is reflection which makes relay to switch to drive
the motor or any other circuit for producing dry air.


Here a bit of troubleshooting is possible. The LED will glow when the
hand will not under the drier.

[Richard Principal]

So what is a TSOP.

[yogi]

tsop is the sensor which detects 38Khz IR

[allenborder]

Hi Friends
Hand dryer is used mostly in restaurant and hotels for drying hands.There are two types of hand driers, one is manually operated through a switch, other is one automatic.in automatic hand drier hand put under the machine and in manually u have to switch on of the machine.
_________________
"God is the only truth in world."