16DecDecember 16, 2025

ESP32 with Dot Matrix Display (MAX7219)

📌 What is the Dot Matrix Display with MAX7219?A Dot Matrix Display is an arrangement of LEDs in a grid (commonly 8x8) used to display text, symbols, numbers, or animations. When combined with the MAX7219 driver chip, it becomes much easier to control multiple displays using just 3 wires (SPI) from the ESP32.🧠 Key Features of Dot Matrix with MAX7219FeatureDetailsDisplay TypeLED Dot Matrix (8x8 per module)Module DriverMAX7219InterfaceSPI-compatible (DIN, CLK, CS)Voltage5V (logic safe for ESP32)CascadableYes (multiple modules side-by-side)Control LibraryMD_Parola / MD_MAX72xxBrightness ControlYes (adjustable via software)⚙️ Pinout of...

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16DecDecember 16, 2025

Motion Detected: ESP32 with PIR Sensor (HC-SR501)

🧠 What is a PIR Sensor?PIR = Passive Infrared SensorA PIR sensor detects motion by measuring changes in infrared radiation.Every warm object (like humans and animals) emits infrared (IR) radiation.PIR sensors don’t emit anything; they only detect IR changes. That’s why they are called passive.🧪 How Does It Work?The PIR sensor has two slots made of pyroelectric sensors.When a human or animal moves in front of the sensor, one slot sees more IR radiation than the other.This sudden change causes a voltage difference and the sensor outputs HIGH (3.3V or 5V) for a short...

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16DecDecember 16, 2025

ESP32 with SIM900A GSM Module

📡 What is SIM900?The SIM900 is a GSM/GPRS module from SIMCom. It allows microcontrollers like ESP32 or Arduino to:✅ Send/receive SMS✅ Make/receive phone calls✅ Connect to the Internet (GPRS)✅ Send data to servers via HTTP, MQTT, TCP/IPIt communicates via UART (TX/RX) and uses AT commands.📦 Features of SIM900FeatureDescriptionNetwork2G GSM (850/900/1800/1900 MHz)CommunicationUART (AT commands)Baud RateDefault 9600SIM CardStandard-size SIM (2G supported)Power Supply5V–12V, 2A recommendedAntennaRequired for GSM signalOptionalMic & Speaker (for calls)🔌 SIM900 to ESP32 ConnectionSIM900 PinESP32 PinTXGPIO 16 (ESP32 RX)RXGPIO 17 (ESP32 TX)GNDGNDVCC⚠️ External 5V 2A power supply⚠️ DO NOT power SIM900 directly from ESP32 or USB....

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15DecDecember 15, 2025

Rotary Encoder with Esp32

23-07-2025📌 What is a Rotary Encoder?A rotary encoder is an electro-mechanical sensor that converts the angular position or motion of a rotating shaft into digital signals. Unlike a potentiometer, it can rotate infinitely in either direction and is commonly used in digital volume knobs, step selection, or menu navigation.There are two main types:Incremental (most common)AbsoluteThe most widely used type with ESP32 is the incremental rotary encoder with a push-button switch.🧠 Key Features of Rotary EncoderFeatureDetailsRotationContinuous 360° (no end stops)Signal OutputDigital (Quadrature: A and B)Additional ButtonBuilt-in push button (optional)ResolutionTypically 20 pulses...

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15DecDecember 15, 2025

DFPlayer Mini with Esp32

🎵 What is DFPlayer Mini?The DFPlayer Mini is a tiny, standalone MP3 audio player module. It can play audio files (MP3/WAV) stored on a microSD card. You can control it through:Serial communication (UART with ESP32 or Arduino)Built-in IO pins (for button-triggered audio)Library-based commands to control volume, play/pause, next, loop, etc.📦 DFPlayer Mini PinoutPinFunctionVCCPower (3.2V–5V)GNDGroundTXSerial Transmit (connect to ESP32 RX)RXSerial Receive (connect to ESP32 TX)SPK1, SPK2Speaker output (mono, 3W)DAC_L/RStereo line out (for headphones/amp)IO1/IO2Button controlBUSYLOW when playing🔌 Wiring DFPlayer Mini with ESP32🔧 ESP32 to DFPlayer Mini (Serial Connection):DFPlayer PinESP32...

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