مراحيض تعمل تلقائيا بدون لمس لمنع انتقال الأمراض ..
يمكن استخدام الدائرة التالية لوضع تصميم مقارب يقوم بتشغيل ذراع ميكانيكي عند وضع اليد بين ثنائي الاشعة تحت الحمراء D2 وبين الترانزيستور الضوئي ..
الدائرة الالكترونية :
Wireless On-Off Switch Circuit diagram
مكونات الدائرة الالكترونية :
R1 = 470R
R2 = 100K
R3 = 3.3K
R4 = 10K
D1 = 1N4007
D2 = IR LED
Q1 = L14F1
RL = 5Vdc Relay
IC = CA3140
Q2 = BC548
Normally home appliances are controlled by means of switches, sensors,
etc. However, physical contact with switches may be dangerous if there
is any shorting. The circuit described here requires no physical contact
for operating the appliance. You just need to move your hand between
the infrared LED (D2) and the phototransistor (Q1).
The infrared rays transmitted by D2 is detected by the phototransistor
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, D2,
phototransistor and other discrete components.
Circuit Operation:
When regulated 5V is connected to the circuit, D2 emits infrared rays,
which are received by phototransistor Q1 if it is properly aligned. The
collector of Q1 is connected to non-inverting pin 3 of IC1. Inverting
pin 2 of IC1 is connected to voltage-divider preset R4. Using preset R4
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 (Q2). The high output of IC1 at pin 6 drives
transistor Q2 to energies 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.
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