This project is a BLE door and window sensor design that uses a U-blox BMD-330-A-R for BLE communication, a reed switch as a sensor, a multi-color LED for status display, and is powered by VBAT. There's also a programming interface and reset switch included. #WiFi #BLE #MCU #ReferenceDesign #project #referenceDesign #simple-embedded #ublox #template #reference-design

Low-power USB-C 5V environmental sensor node with robust input protection, ESP32 Wi-Fi/BLE connectivity, digital temperature/humidity sensing, Bluetooth peripheral syncing, and EEG/PPG sensor interfaces for prototype biosignal acquisition.

Carte STM32F103 2 couches avec alimentation 3,3 V régulée, quartz 16 MHz, USB 2.0 Full-Speed, interface SWD et support de fabrication.

Experimental 21V/5S Li-ion DeWalt battery charger with 21V DC input, relay-switched charge path, tap monitoring, ESP32-WROOM external controller interface, test header, and 2-layer prototype PCB intent.

Raspberry Pi 5 HAT for the Tense Sapphire P.K.E. Meter with two GPIO-driven LEDs, one buzzer, and two GPIO buttons on the 40-pin HAT interface.

Handheld Xbox 360 system with integrated controller electronics, battery-managed USB-C PD power, and a separate dock that automatically switches display, Kinect, and DVD drive paths through a mezzanine docking interface.

Cow health-monitoring wearable PCB for a cow-mounted device. Rear strap electronics target 20-25 g and front sensing assembly target about 15 g. Uses an ESP32-based sensor controller, 200 mAh LiPo battery, battery charging circuitry, and interfaces for ammonia, methane, IR temperature, and saliva sensing. Design must tolerate moisture, mucus, debris, vibration, fur contact, and tongue/lick exposure while remaining compact and lightweight for wearable use.

Glove interface board using Seeed Studio XIAO ESP32S3. Manufacturing path updated for partial assembly: preserve existing glove interface circuitry (FSR inputs on J3-J7, I2C on J8, SPI on J9, pull resistors R1-R7, decoupling C1) and source U1 separately because JLCPCB stock for MPN 113991114 is unavailable. Assemble all other parts normally, leave U1 for customer-supplied/manual installation, and do not substitute U1 unless a verified XIAO-format pin-compatible replacement is explicitly approved.

FlowState Headband EVT1 — 4-Channel EEG Calibration Device Closed-loop EEG neurofeedback headband for theta/beta baseline calibration. 4-layer mixed-signal PCB, 40x30mm. Core ICs: - ADS1299-4PAG (TI) — 4-channel 24-bit EEG analog front end, SPI interface, 250 SPS - nRF5340 (Nordic) — Dual-core BLE 5.3 SoC, 128 MHz app core + 64 MHz network core Key requirements: - Separate analog and digital power domains (dual LDO: LP5907 for AVDD, AP2112 for DVDD) - Split analog/digital ground planes with single-point connection - 6 electrode inputs (4 active + 1 reference + 1 DRL) with individual TVS ESD protection on each - LIS2DH12 accelerometer (I2C) for motion artifact detection - MCP73831 USB-C battery charging (300-500 mAh LiPo) - 2.4 GHz chip antenna or PCB trace antenna at board edge with 10mm keepout - Conformal coating for sweat/moisture protection Reference designs: - Analog front-end: TI ADS1299 EVM (SBAS499) - Digital/BLE: Nordic nRF5340 DK reference schematic Critical constraint: Microvolt-level EEG signals — analog input routing and power supply filtering are the highest-priority layout concerns.

Wearable closed-loop ultrasonic monitoring and transcutaneous neuromodulation system based on ESP32-C3, powered from a 7.4 V 1000 mAh LiPo battery with TP4056 charging, MT3608 boost conversion, AMS1117-3.3 regulation, JSN-SR04T ultrasonic sensing, LED and buzzer alerts through a BC547 driver, and a reserved neuromodulation interface for future integration.

SCADA Sensor Node v2.1 using a Heltec WiFi LoRa 32 V4 module with separate +5V and board-generated +3V3 rails, ADS131M08 8-channel ADC front end, TCA9548A I2C multiplexer, TMP102-based fan control, ULN2003A relay and fan driver, CT/pressure/analog/One-Wire/vibration/humidity/Qwiic/flow/digital sensor interfaces, relay outputs, fan connector, brownout sensing, and a 200 mm x 140 mm 2-layer layout with Heltec keepout, antenna clearance, mounting holes, and DIN-rail slots.

Datasheet-driven MFRC522 RFID reader PCB intended to replicate RC522 module behavior at 13.56 MHz with a 3.3 V nominal supply, 2.5 V to 3.3 V operating range, and RC522-style 8-pin host header compatibility. The MFRC522 datasheet is the authoritative source for pin usage, power rail relationships, oscillator requirements, reset/IRQ handling, and antenna interface topology. AVDD, DVDD, and TVDD must be tied to the same 3.3 V rail; PVDD must be equal to or lower than DVDD; unused MFIN must be tied to SVDD or PVSS; SVDD must be tied to a valid supply if not used independently. The design must use a 27.12 MHz crystal meeting CL 10 pF and ESR <= 100 ohms, local 100 nF decoupling on each MFRC522 supply grouping plus bulk capacitance, and an RF front-end based on the MFRC522 application diagram and reference reader matching/tuning network. PCB priorities are short crystal and RF connections, compact placement of decoupling capacitors at supply pins, solid ground reference, and protected antenna region with minimal digital routing through the RF area.

Driver drowsiness detection ECG front end based on the AD8232 with ECG electrode interface, analog signal conditioning, a dedicated 50 Hz twin-T notch filter for power-line interference rejection, regulated low-noise analog power, and a downstream conditioned ECG output prepared for processing and fatigue/drowsiness analysis.

Wearable health device prototype schematic with ECG sensing via AD8232, motion sensing via BNO085 or BMI270 IMU breakout, on-board processing using TI TM4C123G LaunchPad or MSPM0G3507 LaunchPad, optional ESP8266 Wi-Fi, LiPo battery charging with MCP73831, regulated 3.3 V power from TPS63031 buck-boost or AP2112 LDO prototype option, and user interfaces including electrode connector, JST battery connector, programming header, and optional on/off switch.

MagicGlow smart key tray annular PCB with dual WS2812B rings, ESP32-C6 control, HX711 load-cell interface, USB-C power/UART access, buzzer, and button.

Self-Powered RF Transceiver Module for EM Sensing with RF Prescaler, Divider Chain, and ESP32-S3 Interface

Single-project implementation of the Blue Ant AMP Architecture Rev2 using one shared schematic with six logical board partitions: PCB-01 phono stage, PCB-02 input selector and relay attenuator interface, PCB-03 balanced driver and RCA-to-balanced conversion interface, PCB-04 dual logical power amplifier channels, PCB-05 multi-rail power supply, and PCB-06 isolated control and display. Explicit inter-partition connector interfaces and named nets preserve balanced signal handling after RCA conversion, distinct rail domains (+63V, -63V, +15V, -15V, +5V, +3.3V), and documented hard constraints including low-noise analog isolation and high-voltage domain separation.

CNC hydraulic press brake controller with STM32H743, ADS1256, 5x DAC8501 ±10V outputs, 3x AD598 LVDT interfaces, isolated 24V digital inputs, 100BASE-TX Ethernet, watchdog, E-stop hardware disable, and 4-layer 220mm x 160mm PCB architecture. Domains: field 24V I/O, precision analog, logic/Ethernet. Safety behavior: E-stop and valve-disable force all analog command outputs to 0V-safe state and disable field enables; watchdog and power-good supervisor reset MCU on comms or rail faults. PCB constraints: L1/L4 signal+components, L2 solid GND, L3 power plane, 1.0mm board inset margin, RJ45 at edge, field connectors on opposite edge, isolation corridor between field wiring and logic/Ethernet, 4x M4 plated mounting holes inset 10mm from corners.

This project is designed to measure water level of two tanks using ultrasonic sensors interfaced with the ESP32 microcontroller. The design leverages the processing power and wireless connectivity of the ESP32 to accurately monitor water levels and support automated water management processes. Key components include two ultrasonic sensors for precise distance measurement, robust voltage regulation using an LM2596 buck converter, and reliable power management circuits. Its modular design approach facilitates easy expansion and integration with other systems, making it an ideal solution for both DIY enthusiasts and professionals in automated fluid control and IoT applications. #ESP32 #UltrasonicSensor #WaterLevelSensor #LM2596 #VoltageRegulator #ModularDesign #IoT #DIYProjects #ElectronicsDesign #automation

XIAO-Compatible 915MHz RF Shield with Wio-LR1121 Module and u.FL Interface

INTENT: medium complexity / high density USECASE: potential torture test for trace suggestions while routing vs/ routing the entire board; can incremental trace suggestions still be useful (how much context do they need to consider to be good), or does this only make sense as a whole-board problem given the density challenges? ––––––––––––––––––––––––– OBD2 to UART interface dev board. Alternative to deprecated ELM237 Chipset. Documentation: - Power tree: https://drive.google.com/file/d/1oG5_56AuaiLtG3buUaOyhg63TMySnYF3/view?usp=sharing

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Two-PCB low-noise EEG system: Digital board (ESP32-S3-MINI-1U + ADS1299 + CP2102N + USB-C + 1S Li-ion charger/power-path + DF40 mezzanine) and Analog board (3x ADS1299 + REF/BIAS/DRL + driven-shield electrode interfaces + local low-noise regulation + test points). DF40 mezzanine carries only power + digital SPI/control with shared SPI, shared START/RESET, and separate CS/DRDY per AFE. 4-layer stacks with strong analog/digital partitioning and interleaved GND pins on DF40.

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

SmartDeskPet v1.0 Shield Stage 1 status: - Goal: 5V input -> dual AMS1117-3.3 rails (+3V3_MCU and +3V3_WIFI) with common GND. - Note: Keep power nets explicitly named (avoid unnamed nets) to keep ERC happy. Stage 1 completion checklist: - Mark J1 Pin_1 (+5V) as a Power Output pin to satisfy ERC power-driver checks. - Verify all GND symbols/returns are on the same GND net. - Keep +5V_SERVO isolated from the main +5V net (only share GND). Stage 2 preparation notes (MPN/LCSC + layout constraints): - MPN/LCSC targets to define before Stage 2 exit: - AMS1117-3.3 (SOT-223): set exact MPN and (optionally) LCSC PN for both U1 and U2. - 100nF capacitor (0603): set MPN/LCSC for all 0603 100nF decouplers. - 4.7k resistor (0603): set MPN/LCSC for I2C pull-ups R1 and R2. - 1000uF bulk capacitor (radial): set MPN/LCSC for C7 (CP_Radial_D10.0mm_P5.00mm). - DC005 power jack/regulator input: select exact DC005 footprint + MPN/LCSC (if used). - 2.54mm headers/sockets: set MPN/LCSC for H1, H2, J1, J3, J4, J5, P3, P4, P5, and J2. - ESP-01S antenna keepout: - Reserve a copper keepout under and in front of the ESP-01S onboard antenna. - No copper pours/traces/components in the antenna region (top and bottom) per module guidelines. - H1/H2 header spacing: - Maintain 1000 mil spacing between H1 and H2 header centerlines (shield mechanical requirement). - Silkscreen placeholders: - Add silkscreen labels for: 5V IN, GND, +3V3_MCU, +3V3_WIFI, SERVO1, SERVO2, I2C SDA/SCL, DHT11, ASRPRO UART2, ESP-01S UART3. - Add placeholder text for: MPN, LCSC, board revision, and date code. Stage 3 layout constraints (placement and routing guidance): - Connector placement strategy: - Place H1 and H2 first to lock the shield mechanical interface; enforce 1000 mil spacing. - Place J1 and any DC005 input at the board edge for easy access. - Designated power area planning: - Group U1, U2, and C7 near the 5V entry point; keep high-current 5V and regulator loops short. - Use wide copper for +5V and any servo supply; stitch GND around power section. - Antenna keepout boundaries: - Place J2 (ESP-01S socket) at a board edge with the antenna facing outward. - Enforce a top-and-bottom copper keepout in the antenna region; keep noisy power traces away.