The 20-second period can be checked with wristwatches and the stopwatches on mobile phones, but these are not convenient to use while washing hands. This proposed circuit rings a buzzer for 20 seconds and switches on an LED for audio as well as visual indication (for those with hearing issues). The author's prototype is shown in Fig. 1.
The circuit for this alarm, shown in Fig. 2, comprises a 9V battery, 5V voltage regulator LM7805 (IC1), timer NE555 (IC2), relay driver ULN2003 (IC3), 5V SPDT relay (RL1), and a few other components.
Resistor R2 and capacitor C2 decide the time of monostable, which is around 20 seconds here. This output time period of IC2 at its pin 3 (monostable multivibrator built around NE555) can be calculated using following relationship:
T = 1.1RC
where R = R2 = 18k and C = C2 = 1000μF.
هذه القصة مأخوذة من طبعة January 2023 من Electronics For You.
ابدأ النسخة التجريبية المجانية من Magzter GOLD لمدة 7 أيام للوصول إلى آلاف القصص المتميزة المنسقة وأكثر من 9,000 مجلة وصحيفة.
بالفعل مشترك ? تسجيل الدخول
هذه القصة مأخوذة من طبعة January 2023 من Electronics For You.
ابدأ النسخة التجريبية المجانية من Magzter GOLD لمدة 7 أيام للوصول إلى آلاف القصص المتميزة المنسقة وأكثر من 9,000 مجلة وصحيفة.
بالفعل مشترك? تسجيل الدخول
STK435 IC-Based STEREO AMPLIFIER
This stereo AF amplifier uses the STK435 IC, a highly popular choice due to its simplicity.
A SEWER DRAIN SHIELD For Smart Cities
Drainage systems are vital for storm water management but often transport pollutants, especially plastics, to rivers and oceans, harming ecosystems.
ESP32 SPEECH FUNCTION: Text To Speech
Speech capability in technology primarily has two dimensions: text to speech (TTS) and speech to text (STT). This device focuses on TTS.
World's Smallest Programable INDUSPHONE DESIGN
This is the second part of designing the world’s smallest phone, where the UI is integrated with the basic functions of the phone.
FLAME-SENSING FIRE ALARM Using An Arduino Nano
Fire safety alarms are crucial in both residential and industrial environments.
loT-Based Distribution Transformer CONDITION MONITORING SYSTEM
The proposed IoT-based distribution transformer condition monitoring system enables real-time monitoring of distribution transformers, identifying such deviations as overload conditions and overheating.
Wi-Fi 6 AND Wi-Fi 7 Powering The Next Wave of Smart Connectivity
Wi-Fi 6 leads with faster data rates and reduced latency while upcoming Wi-Fi 7's backward compatibility will facilitate gradual upgrades from Wi-Fi 6, easing transitions. However, advanced features like multi-link operation (MLO) and ultra-low latency may command a premium, making Wi-Fi 7 suited for high-end applications.
CHARGE FORWARD: High-Voltage Batteries And MSMEs Can Fuel INDIA'S EV REVOLUTION
A nuanced explanation of low- and high-voltage EV batteries by Dr Gokhale, Vice President for Battery Technology at JSW Energy, illuminates their advancements and influence. The essential role of MSMEs and academia in developing a strong EV ecosystem emerges, marking their significance for India's push towards self-reliance in this innovative field.
"MILES TO GO Before I Sleep"
A teacher illuminates the path to success through the light of knowledge, yet some teachers extend that light to society through their contributions and research. Known as the architect of the modern M3 electronic voting machine (EVM) and the voter verifiable paper audit trail (VVPAT) that transformed India's democratic process, Prof. (Dr) Rajat Moona's journey began in the modest town of Bareilly. Here is his story, as recounted to and written by EFY's Yashasvini Razdan.
STARTUPS & INNOVATORS
1 One Charger To Charge All Your Devices | 2 Harnessing AI Technology For Efficient Pest Management | 3 Wireless Light-Based Communication With Velmenni's Technology
