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  AUTOMATIC STREET LIGHT SYSTEM 1. Aim To design and demonstrate an automatic street light control system using an LDR (Light Dependent Resistor) and a two-transistor switching circuit. 2. Components Used S.N Component Function 1 LDR (Light Dependent Resistor) Senses environmental light level 2 Q1 – NPN Transistor Acts as day/night sensor switch 3 Q2 – NPN Transistor Drives the LEDs (load switching) 4 R1 – 33kΩ Resistor Load output resistor for Q1 to prevent short circuit & limit current 5 R2 – 1kΩ Resistor Base resistor for Q2 to limit trigger current 6 Potentiometer – 100kΩ Adjusts sensitivity/trigger threshold for Q1 7 3.7V Lithium-ion Battery Power supply (recommended due to lack of LED current limiting...
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  AUTOMATIC HAND SANITIZER DISPENSER 1. Aim To design and construct an automatic hand sanitizer dispenser using an infrared (IR) sensor and MOSFET-based switching to operate a water pump. 2. Components Used S.N Component Purpose 1 Infrared LED (IR Emitter) Emits invisible IR light toward the detection area 2 Photodiode (IR Receiver) Receives reflected IR light when an object is present 3 IRFZ44N MOSFET Acts as an electronic switch to control the pump 4 Water Pump (3–6V) Dispenses sanitizer liquid 5 Resistors (R1, R2, R3) R1 → limits IR LED current R2 → reverse bias for photodiode R3 → noise control, pulls signal to ground 6 3.7V Lithium-ion Battery Power supply for the entire circuit 3. Circuit Description   ➤ IR Em...
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  PIR sensor: fig.(a) experimental circuit diagram fig.(b) power supply fig.(c) relay module fig.(d) pir sensor fig.(e) over all connection here one phase and neutral remains    1. AC to DC Power Supply Section (Left side of the circuit)fig(a) This part converts 230V AC mains to 5V DC , which is needed to power the PIR sensor and the relay section. 1.1 Capacitive Dropper (C1 + R1 + R5) C1 (105J) drops the AC voltage without heating (reactive dropper). R1 (1MΩ) discharges the capacitor when power is off (safety bleed resistor). R5 (100Ω, 1W) limits inrush current and protects the diodes. This replaces a transformer and produces a low-current AC voltage. 1.2 Bridge Rectifier (D1, D2, D3, D4) These four 1N4007 diodes convert AC to DC. 1.3 Filtering Capacitor (C2) Smooths the pulsating DC. Stores charge so PIR sensor gets stable power. 1.4 Zener Regulation (D6 – 5V Zener) Keeps the ...
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'' !! What is SoftAP? The Secret Behind Offline ESP32 Projects !!''

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    '' What is SoftAP Mode ? '' SoftAP stands for Software-enabled Access Point . When an ESP32 runs in SoftAP mode , it creates its own Wi-Fi network — just like a Wi-Fi router. Devices like phones or laptops can connect directly to the ESP32 , without needing a separate router or internet. ESP32 Operating Modes Mode Description STA Station mode (ESP32 connects to existing Wi-Fi) AP (SoftAP) Access Point mode (ESP32 creates a Wi-Fi network) STA + AP Dual mode (ESP connects to Wi-Fi and acts as hotspot)                                                                                         ...
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''How Satellites Track You: GPS Trilateration in Simple Words''

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'' 👉 GPS Trilateration Example – How Your Device Finds Your Location Using Satellites ''   Introduction: What is GNSS? GNSS stands for Global Navigation Satellite System . It refers to satellite systems that provide global positioning services. Some popular GNSS systems include: GPS (USA) GLONASS (Russia) Galileo (European Union) BeiDou (China) NavIC (India – regional) QZSS (Japan – regional) Among them, GPS (Global Positioning System) is the most widely used, and today we'll explore how GPS finds your exact location using a technique called trilateration . GPS (Global Positioning System) is a navigation system that uses satellites to determine the exact location (latitude, longitude, and altitude) of a person or object anywhere on Earth. What is GPS Trilateration? Trilateration is the method used by GPS to calculate your position using distances from satellites in space. Imagine three satellites draw spheres around themselves, and...
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