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.
This story is from the {{IssueName}} edition of {{MagazineName}}.
Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 9,000+ magazines and newspapers.
Already a subscriber ? Sign In
This story is from the {{IssueName}} edition of {{MagazineName}}.
Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 9,000+ magazines and newspapers.
Already a subscriber? Sign In
Wearable Automatic ASSISTANCE GLOVE
This proposed prototype works by wearing the glove and either touching a specific finger with the thumb or pressing a special switch.
BLUETOOTH CONTROL Through Mobile
Creating a Bluetooth-controlled device with an Arduino Uno and an HC-05 Bluetooth module enables control of lights or even relays to manage AC appliances wirelessly using an Android smartphone.
Raspberry-Pi Based WAVEFORM GENERATOR
A waveform generator is a commonly used test and measurement instrument in electronics laboratories.
World's Smallest Programable INDUSPHONE DESIGN
Smartphones have become a necessity in daily life.
AUTOMATIC WIPER CONTROL For Three/Four Wheelers
The integration of a 555 timer and L293D motor driver in an automatic wiper control device presents a practical and efficient solution for enhancing driver safety and convenience.
EMS Vs Components Manufacturing: EMPLOYMENT IN ELECTRONICS INDUSTRY OF INDIA
A recent article in a leading business newspaper reported that industry executives, during a government meeting, had suggested that EMS firms create more employment than electronics component manufacturers-for every rupee invested. To verify this claim, a review was conducted with both component manufacturers and EMS firms, as well as several trade associations.
Why Did Rajguru Electronics, A Leading Distributor Of Components And Development Boards, Enter Manufacturing?
After nearly three decades in distribution, Rajguru Electronics pivoted to manufacturing, setting up a unit for its ADIY subsidiary in Bengaluru. EFY's Yashasvini Razdan interviewed CEO Dileep Jain to explore the reasons behind the shift and the company's growth strategy.
"We Are Building FUTURE ENTREPRENEURS With Drone Assembly And Maintenance Training"
AVPL is creating village-level entrepreneurs and jobs through drone technology and agriculture training. In an interview with EFY's Nitisha, Co-founder and Chairman Preet Sandhu discloses how their 70 centres across 12 states offer offline courses in RPC and agricultural spraying.
"Becoming CLEAR"
From a nonchalant teenager to authoring a book on Verilog at 25 and launching successful IPOs for startups on the US stock market, Rajeev Madhavan exemplifies how the right guidance can transform a life. This is the story of one of Silicon Valley's most influential venture capitalists, as narrated to Yashasvini Razdan.
THINKRAW INDIA'S SOLAR SOLUTIONS FOR THE AGRICULTURAL SECTOR
ThinkRaw's blend of technology and tradition is revolutionising agriculture with solar-powered solutions that enhance efficiency and sustainability in farming and aquaculture.
