Multi-subsystem ESP32-S3 coffee maker/alarm controller board for a Coffee Waker appliance. The design uses an ESP32-S3-WROOM-1-N8R8 module as the main Wi-Fi/Bluetooth MCU, with USB-C 2.0 device connectivity through a USB4105-GF-A connector, 5.1 kΩ CC pull-downs, and USBLC6-2SC6 ESD protection on the USB D+/D− pair. Power architecture includes a 12 V input on a JST VH B4P connector, a TPS62932 buck regulator generating the 5 V rail, a TLV1117LV33 3.3 V LDO for MCU/logic power, and TPS22919 load switches for controlled 3.3 V/5 V peripheral rails. Functional blocks include an NAU7802 load-cell ADC on I2C with two differential load-cell channels, a MAX98357A I2S audio amplifier/DAC with speaker/output filtering, a microSD socket on SDIO, I2C/test headers, UART/programming header, and auxiliary JST VH connectors for wake-light or external loads. The high-voltage section includes 120 VAC input/output screw terminals, a 5 V SPST-NO relay rated 15 A / 240 VAC max, a 1 A fuse, MOV surge suppression, diode snubber, and a dedicated heater output terminal.

STM32F103-based GLECS V4 pure logic controller with 12V input power tree, onboard 4G module, isolated relay control zone, sensors, OLED, debug headers, and 200x140mm two-layer PCB requirements.

Industrial 415V 3-phase motor control interface with STM32 command logic, SIMCom A7672S 4G SMS control, isolated relay driver, 12V input power, and 150x100mm 2-layer PCB constraints.

Industrial motor controller PCB with 12V relay switching zone isolated from STM32/4G LTE logic zone by a routed vertical isolation slot on a 150x100mm 2-layer FR4 board.

Industrial-grade RP2350B controller with W5500 Ethernet, 24V input power, isolated industrial I/O, RS485, USB hub, relay outputs, and robust connector protection for -40°C to +85°C consumer/industrial use.

Compact Li-Po powered ESP32 wearable vibration alert prototype for construction worker safety monitoring, using a relay module to directly switch a 3V coin vibration motor with beginner-friendly soldering and labeled PCB wiring.

Robust ESP32-S3 N16R8 44-pin baseboard for MG90S servos, SPI TFT, I2C OLED/INA226 modules, buzzer, and 12V MOSFET load/filter relay channels with EMI-conscious power distribution.

ESP32-based universal inline analog signal conditioner with protected sensor input, DAC output, fail-safe NC relay passthrough, OLED UI, Bluetooth profile logic, and terminal-block I/O for automotive/bench use.

UK Smart Wall Switch Back Board: 802.3af PoE-powered 65x65mm relay and energy-monitoring back board with RJ45, isolated 5V/3.3V rails, W5500 Ethernet, BL0942 metering, touch ICs, and 12-pin pogo interface.

Golf ball dispenser controller with protected 12V-24V DC input, LM2596 5V buck, ESP32 control, INA219 relay-coil sensing, and dry-contact relay output.

Reusable ESP32-WROOM golf ball dispenser interface board with protected 12V to 24V input power, one conditioned coin pulse input, SPDT relay dry-contact output, open-collector output, Bluetooth pulse generation, screw-terminal field wiring, and optional UART programming access.

Have you ever wanted to wake up to one of the most energizing scents? Have you ever wanted that cup of energy in your hands before you even slide out of your covers? Well want no further! Introducing the Coffee Waker; The knight of your nightstand, a coffee maker alarm clock with one soul purpose, to quickly and scrumptiously wake you up. This is the Coffee Waker Main board. It contains an ESP32-S3, 16 bit Load Cell ADC, 16 bit MP3 DAC, 120V heater cartridge relay, and 12C wakeup light convector.

Multi-device wireless control system using a Seeed Studio XIAO ESP32-C3, 433 MHz ASK receiver, 5 V relay drivers, AMS1117-3.3 regulator, input protection, and PCB isolation between low-voltage control and relay output sections.

STM32F401 Blackpill-style railway crossing safety controller with dual 12V input selection, LM2596 5V buck, AMS1117-3.3 MCU rail, horn relay driver, and edge-mounted off-board sensor, servo, and UART connectors for modular prototyping.

ESP32-S3 door access controller with USB-C Li-ion charging, VBAT and 12V lock power, dual 3.3V rails, I2C sensor headers, reed/PIR inputs, LED indicators, buzzer, and MOSFET plus relay lock outputs. External modules and field devices remain represented by connector placeholders with documented pinouts for later PCB and validation work.

Battery management system PCB-A for an off-grid 12 V AGM lead-acid battery with current sensing, voltage and temperature monitoring, ESP32 control, relay output, split PGND/AGND grounding, and JLCPCB-ready 2-layer layout constraints.

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.

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.

ESP32-S3-WROOM 12V Relay Controller: 8x Opto-Isolated 127/220VAC Inputs, 8x 10A NO/COM Relays, Wi-Fi/BLE/Ethernet, I2C/SPI

Udayan Project 35K – JFET Guitar Compressor/Preamp Pedal with Relay True Bypass

4-Channel Secure 433 MHz Automotive Relay Receiver with STM32G071 and RFM69HCW, featuring a 16-pin Digi-Key right-angle ≥10 A/circuit connector, 2 oz copper 10 A traces, AEC-Q200 Digi-Key control passives, and verified LED/pushbutton wiring #automotive #433MHz #STM32G0 #RFM69 #relays #10A #2ozCopper #AECQ200

Relay HAT Schematic – Post‑Validation Fix Plan (ULN2803A, Buck → Pico, LEDs, Optos, Testpoints)

Marine Engine Start Panel Control Board with ESP32-WROOM-32D, 12 V Relay Outputs, PCA9685 LED Drivers, and MOSFET-Based Screen PWM Control

ESP32-WROOM-32 Sensor & Relay Control PCB with Power Management

ESP32 Single Relay Controller with 1.8" ST7735 TFT Display and Enhanced Power Management