Normally, home appliances are controlled by means of switches,
sensors, etc. However, physical contact with switches may be
dangerous if there is any shorting .So here a tip about how to prepare
a wireless switchs
To prepare Wireless switch we need
appliance. You just need to move your hand between the infrared LED
(IR LED1) and the phototransistor (T1). The infrared rays transmitted by
IR LED1 is detected by the photo transistor to activate the hidden lock, flush
system, hand dryer or else.
This circuit is very stable and sensitive compared to other AC appliance
control circuits. It is simple, compact and cheap. Current consumption is
low in milliamperes. The circuit is built around an IC CA3140, IRLED1, photo transistor
and other discrete components.
When regulated 5V is connected to the circuit, IR LED1 emits infrared rays, which are
received by phototransistor T1 if it is properly aligned. The collector of T1
is connected to non-inverting pin 3 of IC1. Inverting pin 2 of IC1 is connected
to voltage-divider preset VR1. Using preset VR1 you can vary the reference
voltage at pin 2, which also affects sensitivity of the phototransistor.
Op-amp IC1 amplifies the signal received from the phototransistor.
Resistor R3 controls the base current of transistor BC548 (T2). The high output
of IC1 at pin 6 drives transistor T2 to energise relay RL1 and switch on the
appliance, say, hand dryer, through the relay contacts.
The working of the circuit is simple. In order to switch on the appliance,
you simply interrupt the infrared rays falling on the phototransistor through
your hand. During the interruption, the appliance remains on through the
relay. When you remove your hand from the infrared beam, the appliance
turns off through the relay.
Assemble the circuit on any general- purpose PCB. Identify the resistors
through colour coding or using the multimeter. Check the polarity and pin
configuration of the IC and mount it using base. After soldering the circuit,
connect +5V supply to the circuit
sensors, etc. However, physical contact with switches may be
dangerous if there is any shorting .So here a tip about how to prepare
a wireless switchs
To prepare Wireless switch we need
- Transistor / SCR
- LED
- Relay
- Resistor and Capacitor
- IC CA 3140
appliance. You just need to move your hand between the infrared LED
(IR LED1) and the phototransistor (T1). The infrared rays transmitted by
IR LED1 is detected by the photo transistor to activate the hidden lock, flush
system, hand dryer or else.
This circuit is very stable and sensitive compared to other AC appliance
control circuits. It is simple, compact and cheap. Current consumption is
low in milliamperes. The circuit is built around an IC CA3140, IRLED1, photo transistor
and other discrete components.
When regulated 5V is connected to the circuit, IR LED1 emits infrared rays, which are
received by phototransistor T1 if it is properly aligned. The collector of T1
is connected to non-inverting pin 3 of IC1. Inverting pin 2 of IC1 is connected
to voltage-divider preset VR1. Using preset VR1 you can vary the reference
voltage at pin 2, which also affects sensitivity of the phototransistor.
Op-amp IC1 amplifies the signal received from the phototransistor.
Resistor R3 controls the base current of transistor BC548 (T2). The high output
of IC1 at pin 6 drives transistor T2 to energise relay RL1 and switch on the
appliance, say, hand dryer, through the relay contacts.
The working of the circuit is simple. In order to switch on the appliance,
you simply interrupt the infrared rays falling on the phototransistor through
your hand. During the interruption, the appliance remains on through the
relay. When you remove your hand from the infrared beam, the appliance
turns off through the relay.
Assemble the circuit on any general- purpose PCB. Identify the resistors
through colour coding or using the multimeter. Check the polarity and pin
configuration of the IC and mount it using base. After soldering the circuit,
connect +5V supply to the circuit
sxdc
ReplyDeletecan you please tell me some important points regarding the alignment of the ir led and photo transistor
ReplyDeletevery good project
ReplyDeletewe are glad that you like it
ReplyDelete