6x Warm-White 5mm LED Ring (2 constant, 4 flicker) on 4.5 V battery w/ high-side SPST and bussed 6x330 ohm resistor network

The "Green Dot 2040E5" Board is a Node that interfaces RS485 Sensor probes and can log information to the cloud using LoRa Connectivity. It uses the XIAO RP2040 and the LoRa-E5 (STM32WLE5JC) modules from Seeed Studio to do its magic. It also has amazing power management capabilities (Solar charging, Battery protection, etc) that make it very useful for IoT applications #internetOfThings #smartHomeDevices #SeeedStudio #XIAO #LoRa #RP2040 #IoT

3.3V ESP32-S3 Dual 6V Rail MOSFET Board with MCP23017 I2C Expanders, Option C Gate Network, SW2 DPST Rail-Interlock, 2S LiFePO4 Charger/BMS (BQ24618 + BQ29209) with Series Battery Wiring and Charge Integration, and 2×10 RA Headers (#MCP23017_3V3 #OptionC #GateNetwork #RailInterlock #Dual6V #BQ24618 #BQ29209 #2S #LiFePO4 #SeriesBattery #ChargeIntegration #RAHeaders)

Two-Bank 6 V Igniter Firing System with Onboard 2S LiFePO4 Pack, S-8252A Protection, BQ24618 LiFePO4 Charger (3 A, 3.6 V Fast, <50 mA Termination, 3.8 V HPPC, 3.5 V Float), 32 SOT-223 MOSFET Outputs via MCP23017, with Reserved PCB Areas for Dual 26650 Holders, 34-pin IDC, and Barrel Jack Input #LiFePO4 #Battery #BMS

Architectural Lavender Translation Collar – ESP32‑S3 Wi‑Fi + LoRa, USB‑C, Li‑ion, low‑power design Overview Experience a cutting-edge IoT solution with this low‑power board built around the ESP32‑S3‑MINI‑1‑N8. Designed for seamless Wi‑Fi (2.4 GHz), BLE, and LoRa (868 MHz) connectivity, this board integrates ENS161 and ENS210 sensors over I2C alongside an RFM95W‑868 LoRa radio on SPI. It is powered via a 3.7 V Li‑ion cell with USB‑C charging up to 500 mA, complete with full battery protection, a robust 3.3 V rail tailored for Wi‑Fi burst currents, and per‑peripheral power gating to enhance energy efficiency. Core Features • MCU: ESP32‑S3‑MINI‑1‑N8 equipped with an onboard PCB antenna for 2.4 GHz Wi‑Fi/BLE, ensuring optimal wireless performance. • Sensors: Integrated ENS161 and ENS210 sensors utilize a shared I2C bus with controllable 4.7 kΩ pull‑ups for streamlined communication. • LoRa Radio: The RFM95W‑868 module, connected via SPI, enables long‑range communication at 868 MHz. Power & USB‑C Connectivity • Battery: A reliable 3.7 V 1200 mAh Li‑ion battery connected via a right‑angle JST‑PH 2‑pin connector features built‑in battery protection. • Charging: The USB‑C receptacle, with CC resistors and TVS protection on D+/D− along with series resistors, supports fast, safe charging with a current limit of 500 mA. • Regulation: A dedicated 3.3 V regulator capable of handling Wi‑Fi burst currents coupled with bulk and high‑frequency decoupling ensures stable operation, supported by status LEDs indicating power and charge states. Low‑Power Control • Peripheral Management: Load switches allow selective power‑gating of the ENS161, ENS210, and RFM95W modules, controlled directly by ESP32‑S3 GPIOs. • Energy Efficiency: Controllable I2C pull‑ups minimize idle current, vital for prolonged battery life in IoT applications. RF and Antenna Integration • 2.4 GHz: Utilizes the integrated PCB antenna on the ESP32‑S3 with proper ground/metal keep‑out zones for optimal signal integrity. • 868 MHz: Features a controlled‑impedance feed from the RFM95W to a PI matching network (C‑L‑C pads) with flexible antenna options—selectable via SMA connector, chip antenna, or PCB trace—and includes RF ESD protection. Connectivity & Debug Features • USB‑C Interface: Provides secure data connectivity with integrated safeguards and proper terminations. • Debugging: A comprehensive programming/debug header exposes EN, BOOT, and UART lines, with test points on key rails and buses (3V3, VBAT, SCK, MOSI, MISO, SDA, SCL, RESET/EN, GND) to simplify development and troubleshooting. Design Verification • Rigorous ERC/DRC and decoupling checks ensure adherence to component ratings and optimal signal routing. • Maintain RF keep‑outs and impedance‑controlled traces for both 2.4 GHz and 868 MHz paths, securing reliable performance even during high‑intensity operations. #IoT #ESP32S3 #LoRa #LowPowerDesign #USB-C #WirelessConnectivity #BatteryPowered #RFDesign

9V Battery 1 Hz LED Blinker Using DIP-8 NE555 (THT) with SPST Switch and Reverse-Polarity Protection

Compact MPPT Solar-Powered Dusk-to-Dawn 0.5 W LED Light with NCP3065 SEPIC Buck-Boost Driver, BQ24650 MPPT Charger, MIC845 Comparator, Vertical JST-PH 2-Pin Battery Connector, Off-Board Solar Input Pads/Optional Connector, Centered Backside LED, 1.4 mm Perimeter Clearance #SEPIC #NCP3065

Smart Wellhead Controller V1.1: ESP32 + LoRa Industrial IoT Node with Solar Power, Deep-Sleep Leak Sensing, and OLED HMI. Now upgraded with a solar charging and battery management stage featuring a TP4056/CN3791 charger IC, power-path switching, Li-ion battery protection, and integrated 3.3 V rail supply. #PowerBlock #SolarCharging #BMS

Low-Power USB-C (5 V) Environmental Sensor Node with 18650 Li-Ion Power-Path, Robust Protection (Reverse Polarity, OVP, UVLO, OCP to 3 A), Dual-Radio ESP32-S3 MCU, I²C VOC/Temp/Humidity/Pressure/Lux Sensors, and 2-/4-Pin JST-XH Expansion Pads for Battery and Sensors #USB-C #LiIon #ESP32 #I2C #PowerProtection #EnvironmentalSensor

PaymentSoundBOX – ESP32 MQTT-Enabled Battery Audio Notifier with Isolated Power, I2S Audio Chain & Integrated UI

Ultra-Compact ESP32 Robotic Control Module with 3S Battery, USB-C PD, 4WD Motor & Servo Support, and Integrated GPS/IMU

ESP32-C3 Smart 3S Li-ion/LiPo Battery Management System with Per-Cell Monitoring and Protection

Seeed Studio XIAO nRF54L15 Board (Pin Header Removed, JST-PH Battery, Pushbutton Added)

Ultra-Compact 4-Layer ESP32-C6 + Quectel EG912U LTE Dev Board w/ Onboard eSIM, π-Match RF Tuning, Optional u.FL, USB-C Data (ESP32-C6 Only), USB-C Battery Charging, Controlled Impedance Routing #EG912U #USBDataOnly #USBCharging #4Layer #eSIM

Optimized EMI Synchronous Buck Converter for CC/CV 4S4P Li-ion Battery Charging & Load Testing (150W, 18–60V to 16.8V/11.5A)

High-Current 28V 7S Li-Ion Battery Management System with Integrated CAN J1939 and Advanced Power Management

ESP32 Motor Driver Board with Sensor, Battery Management, and Peripheral Interfaces

Wi‑Fi/BLE Dual-Mode Portable Stereo Speaker with DSP and Smart Battery Management

Daddy's second circuit board. A sign to let my wife know when I'm on a call. Activates with a slide switch and is powered by USB-C. R2 changes: -Moving to Letter Modules for ease of design -Adding ESP32 for WiFi On/Off and intensity control -Optional: Add unpopulated AA Battery Holder for battery option R1 changes: -Changed LED part to Red LEDs -adjusted resistor value of buck converter -Changed source for USB-C Connector -Removed exposed soldermask on buck converter with negative soldermask expansion -Order with black soldermask Modified by markwu2001: Adjustable Brightness, 85-90% Drive Efficiency <5W Operation (Can use 5V 1A Plug) This project can be purchased from LCSC

A Buck Boost Converter that can be powered from Li ion battery and output 3.3V 500mA Powered by TPS63051YFFR and in the same package as a standard Adafruit Buck Converter. Input Voltage Range: 2.5V to 5.5V

Through-Hole NE555 LED Blinker (1 Hz, 100 ms ON, Diode Steering, 9V Battery)

AvocAudio is a compact tinyML community board designed for extensive audio data collection for various tinyML applications. It leverages the Raspberry Pi RP2040 and integrates a LoRa-E5 LoRaWAN Transceiver Module for connectivity. Equipped with an SD card slot for local data storage, the board ensures efficient data collection. The board operates on solar power or a lithium-ion battery, ensuring flexible and efficient energy use. #audioDevices #raspberryPi #rp2040 #lorawan #iot #solar

System to monitor forest to detect early wildfires. Featuring an Esp32-C6, BME680 module, Solar panel power, Li-Ion battery

A Buck booster that can be powered from Li-on battery ans output 3.3V @ 500mA. Powered by the TPS63051YFFR and in the same package as a standard Adafruit buck converter. Input voltage range : 2.5V to 5.5V

This project is a reference design based on the BQ24075RGTT, a single cell Li-Ion battery charger. It manages the power between an external power source (VIN), a Li-Ion battery (BAT), and a system power rail (SYS). Key features include power-path management, battery thermistor monitoring, and charge status indication. #project #BQ24075 #ReferenceDesign #charger #BatteryManagement #referenceDesign #bms #texas-instruments #template #reference-design