R2 w Thread changes: -Moving to Letter Modules for ease of design -Adding MGM210L for Matter on Thread On/Off and intensity control -Shifted A and R letters closer to fix Kerning -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 Original Description: 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. #template #arduino-matter

IMPORTANT NOTICE: Hey, I opened editing permissions and this doc is broken, see the frozen version here: https://www.flux.ai/markwuflux/on-air-markwu2001-remix-r1-backup-freeze-0b49 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 Original Description: 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.

sEMG-DAQ is a wearable 6 channel data acquisition unit for capturing surface electromyographic (sEMG) signals from human arm muscles using SJ2-3593D jack connectors while conditioning, digitizing, processing and transmitting them as sEMG data to an external AI accelerated board through an SM12B-SRSS IDC connector where AI models are run for various applications including robotic control, muscle signals medical assessment and gesture recognition. The board leverages an INA125P instrumentation amplifier together with filter stages utilizing LM324QT op-amps for conditioning and an STM32G4A1VET6 microcontroller for the digitization, processing and data transmission of the signals. Since AI models can only be as good as the data, the design of such a DAQ is necessary to ensure clean, reliable and real-time data for AI applications requiring sEMG data. The board also has USB-FS and JTAG to cater for debugging. The power (5V) is fed through a screw terminal and is regulated by two LDK320AM LDO regulators to offer 5V, 3.3V and 1.8V to meet the requirements of various components on the board.

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.

5V barrel-powered stepper motor controller board using a TMC2300 driver, a 4-wire JST-PH motor connector, and mechanical motor mounting with two 2 mm holes spaced 20 mm apart plus a centered 8 mm shaft hole.

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.

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.

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

R2 w Thread changes: -Moving to Letter Modules for ease of design -Adding MGM210L for Matter on Thread On/Off and intensity control -Shifted A and R letters closer to fix Kerning -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 Original Description: 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. #template #arduino-matter

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 Original Description: 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. #template

IMPORTANT NOTICE: Hey, I opened editing permissions and this doc is broken, see the frozen version here: https://www.flux.ai/markwuflux/on-air-markwu2001-remix-r1-backup-freeze-0b49 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 Original Description: 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 Original Description: 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. #template

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 Original Description: 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.

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 Original Description: 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 Original Description: 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. #template

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.