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.

The Texas Instruments MSP430FR604x and MSP430FR603x family comprises highly integrated ultrasonic sensing and measurement system-on-chips (SoCs) designed specifically for water and heat metering applications. The featured components, including MSP430FR6047, MSP430FR60471, MSP430FR6045, MSP430FR6037, MSP430FR60371, and MSP430FR6035, deliver best-in-class ultrasonic water flow measurement with ultra-low power consumption. These microcontrollers excel with an active mode current consumption of approximately 120 µA/MHz and a standby mode power draw as low as 450 nA with a real-time clock (RTC) enabled. Key functionalities include a high-precision differential time-of-flight (dTOF) accuracy of less than 25 ps, integrated analog front-end, programmable pulse generation (PPG), and an analog comparator. They also interface directly with standard ultrasonic sensors up to 2.5 MHz and feature up to 256KB FRAM, robust RAM options, and integrated LCD drivers for up to 264 segments. The embedded low-energy accelerator (LEA) enhances digital signal processing capabilities, making these components ideal for battery-powered metering solutions. Peripherals include multiple enhanced serial communication interfaces, high-performance ADCs, DMA controllers, and a suite of timers and encryption modules. These features combine to offer a powerful solution for high-accuracy, low-cost, and ultra-low-power metering applications.

LCD timer with Arduino that uses an encoder to set the time. The code works but it's limited, feel free to upgrade Feel free to review the board.

ESP Dev-Kit V1 breakout board with connections to LCD screen and DHT Temperature Sensor.

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.

This project is a wireless wearable glove (smart glove) for sign language translation. It uses Arduino Nano - ATMega328P, Accelerometer - ADXL345 and a Bluetooth module HC -05 to transmit and display the signs on any compatible display device like a mobile phone or a LCD - LM016L. In this project, I have used a 5x8 LCD display - LM016L to display the test converted. (strings, numbers etc.)

Designing a control board for a smart vending machine. Board will house an ESP32, AC and DC power supply, terminal port for stepper motor, MG990 servo motor, SIM7200 GSM module, 2004 LCD screen.

PCB simulating a piano with the capability of producing sound and images using buttons, LED, LCD, speaker, and a DAC of resistors.

gLCD - Golf Cart LCD

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

@COPILOT Elimina piezas que tengan elementos metálicos en su estructura. El sistema cuenta con un sensor infrarrojo y uno inductivo, el primero detecta la presencia de una ficha en la zona y el segundo, identifica si una ficha contiene un elemento metálico. Si el sensor inductivo se activa se debe expulsar la ficha con el pistón, esta zona contabiliza el número de piezas rechazadas y las visualiza en un Display LCD

This is a climate control system reference design with a STM32WB5 microcontroller, power manager IC, USB Type-C, JST connectors, and an LCD driver. #referenceDesign #edge-computing #edgeComputing #stm #template #iot #control #BLE #reference-design

Control de un LCD1602 (HD44780) en modo paralelo de 8 bits con Arduino Uno R3, ajuste de contraste por potenciómetro, retroiluminación con resistencia en serie y desacoplo con condensadores de 100 nF y 10 µF

lcd de 16x02 donde al insertar tres diferentes tipos de apellidos de personas aparezcan en la pantalla del lcd atravez de tres diferentes push botton donde al presionar el primer push botton aparezca el primer apellido, al presionar el segundo push botton aparezca el segundo apellido y al presionar el tercer push botton aparezca el tercer apellido y que los apellidos aparezcan en la pantalla por alfabeto.

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.

Welcome to your new project. Imagine what you can build here.

Breadboard-only schematic for an ESP32-based LC electromagnetic response visualizer using a handmade coil oscillator, LM339 comparator, GPIO27 frequency input, SSD1306 I2C OLED, and calibration button. No PCB layout is included.

100 W Bridged Class-AB Audio Power Amplifier with LTP Input, VAS Miller Compensation, Complementary MJE340/350 Drivers, 2SC5198/2SA1941 Outputs, Zobel Network, and LC Output Filter on ±14 V Rails

TECHNICAL ASSIGNMENT AND DESIGN GUIDE Active Three-Way Crossover on NE5532 Powered by AM4T-4815DZ and Amplifiers TPA3255 (Updated Version) 1. GENERAL PURPOSE OF THE DEVICE The goal of the development is to create an active three-way audio crossover for one channel of a loudspeaker system, working with the following drivers: LF: VISATON W250 MF: VISATON MR130 HF: Morel MDT-12 Each frequency range is amplified by a separate power amplifier: LF: TPA3255 in PBTL mode (mono) MF + HF: second TPA3255 in stereo mode (one channel for MF, the other for HF) The crossover accepts a single linear audio signal (mono) and divides it into three frequency bands: Range Frequency Range LF 0 – 650 Hz MF 650 – 2500 Hz HF 2500 Hz and above Filter type: Linkwitz–Riley 4th order (24 dB/oct) at each crossover point (650 Hz and 2500 Hz). The crossover must provide: minimal self-noise; no audible distortion in the audible range; stable operation with NE5532 at ±15 V power supply; easy adjustment of the level for each band, as well as the overall level (via the input buffer). 2. FILTER TYPES AND BASIC OPERATING PRINCIPLES Each filter is implemented as two cascaded Sallen–Key 2nd order (Butterworth) stages, resulting in a final 4th order LR4 filter. Topology: non-inverting Sallen–Key, optimal for NE5532. For all stages: Cascade gain: K ≈ 1.586 This provides a Q factor of 0.707 (Butterworth), which in combination gives a Linkwitz–Riley 4th order. 3. COMPONENT VALUES FOR FILTERS 3.1 Universal Parameters RC chain capacitors: 10 nF, film capacitors, tolerance ≤ 5% Resistors: metal-film, tolerance ≤ 1% The gain of each stage is set by feedback resistors: Rf = 5.9 kΩ Rg = 10 kΩ K ≈ 1 + (Rf / Rg) ≈ 1.59 The circuit should allow for the installation of a small capacitor (10–47 pF) in parallel with Rf (footprint provided) for possible stability correction (not mandatory to install in the first revision). 3.2 650 Hz Filters (Low-frequency boundary for MF) These are used for the division between W250 and MR130. LP650 — Low-frequency Filter 2nd Order R1 = 24.9 kΩ R2 = 24.9 kΩ C1 = 10 nF C2 = 10 nF Two stages: LP650 #1 and LP650 #2. HP650 — MF High-frequency Filter 2nd Order Same values: R1 = 24.9 kΩ R2 = 24.9 kΩ C1 = 10 nF C2 = 10 nF Two stages: HP650 #1 and HP650 #2. 3.3 2500 Hz Filters (Upper boundary for MF) These are used for the division between MR130 → MDT-12. LP2500 — High-pass MF Filter R1 = 6.34 kΩ R2 = 6.34 kΩ C1 = 10 nF C2 = 10 nF Two stages: LP2500 #1 and LP2500 #2. HP2500 — High-frequency Filter Same values: R1 = 6.34 kΩ R2 = 6.34 kΩ C1 = 10 nF C2 = 10 nF Two stages: HP2500 #1 and HP2500 #2. 4. OPERATIONAL AMPLIFIERS The NE5532 (dual op-amp, DIP-8 or SOIC-8) is used. A minimum of 4 packages (8 channels) for filters: NE5532 Function U1A, U1B LP650 #1, LP650 #2 (LF) U2A, U2B HP650 #1, HP650 #2 (Lower MF cut-off) U3A, U3B LP2500 #1, LP2500 #2 (Upper MF cut-off) U4A, U4B HP2500 #1, HP2500 #2 (HF) Additionally: U5 — input buffer / preamplifier (both channels) If necessary, an additional NE5532 (U6) for the balanced input (see section 6.2). All NE5532 should have local decoupling for power supply (see section 5.1). 5. CROSSOVER POWER SUPPLY AM4T-4815DZ DC/DC module is used: Input: 36–72 V, connected to the 48 V power supply for TPA3255 amplifiers. Output: +15 V / –15 V, up to 0.133 A per side. Maximum output capacitance: ≤ 47 µF per side (according to the datasheet). 5.1 Power Filtering Input (48 V): RC variant (simpler, acceptable for the first revision): R = 1–2 Ω / 1–2 W C = 47–100 µF (for 63 V or higher) LC variant (preferred for improved noise immunity): L = 10–22 µH C = 47–100 µF The developer may implement LC if confident in choosing the inductance and its parameters. Output +15 V and –15 V (general filtering): Electrolytic capacitor 10–22 µF per side 100 nF (X7R) per side to GND Local decoupling for NE5532 (REQUIRED): For each NE5532 package: 100 nF between +15 V and GND 100 nF between –15 V and GND Place as close as possible to the op-amp power pins (short traces). Additional local filtering for power lines: For each NE5532, decouple from the ±15 V main rails: Either 4.7–10 Ω resistor in series with +15 V and –15 V, Or ferrite bead in each rail. After this component, place local capacitors (100 nF + 1–4.7 µF) to ground. 6. INPUT TRACT: INPUTS, BUFFER, ADJUSTMENT 6.1 Unbalanced Input (RCA / Jack / Linear) The main mode is the unbalanced linear input, for example, RCA. Input tract structure: RF-filter and protection: Signal → series resistor Rin_series = 100–220 Ω After resistor — capacitor Cin_RF = 470–1000 pF to GND This forms a low-level RF filter and reduces high-frequency noise. DC-block (low-pass HP-filter): Capacitor Cin_DC = 2.2–4.7 µF film in series Resistor to ground Rin_to_GND = 47–100 kΩ Cut-off frequency — negligible in the audio range but removes DC. Input buffer / preamplifier (NE5532, U5): Non-inverting configuration. Input — after DC-block. Gain: adjustable, e.g., Rg_fixed = 10 kΩ (to GND through trimmer) Rf = 10–20 kΩ + footprint for trimmer (e.g., 20 kΩ) The gain should be in the range of 0 dB to +10…+12 dB. Possible configuration: Rg = 10 kΩ fixed Rf = 10 kΩ + 10 kΩ trimmer in series. This allows adjusting the overall level of the crossover according to the source and amplifier levels. Buffer output: A low-impedance output (after NE5532) This signal is simultaneously fed to the inputs of all filters: LP650 (LF) HP650 → LP2500 (MF) HP2500 (HF) 6.2 Balanced Input (XLR / TRS) — Optional, but laid out on the board The board should allow for a balanced input, even if it’s not used in the first revision. Implementation requirements: XLR/TRS connector (L, R, GND) or separate 3-pin header. Simple differential receiver on NE5532 (extra U6 package or use one channel of U5 if sufficient). Circuit: classic instrumentation amplifier or differential amplifier: Inputs: IN+ and IN– Output — single-ended signal of the same level (or slightly amplified), fed to DC-block and buffer (or directly to the buffer if integrated). Switching between balanced/unbalanced mode: Implement using jumpers / bridges or adapters: Either switch before the buffer, Or use two separate pads, one of which is unused. All balanced input grounds must be connected to the same AGND point as the unbalanced input to avoid ground loops. 7. LEVEL ADJUSTMENT OF BANDS (BEST METHOD) The level adjustment of each band (LOW, MID, HIGH) is required to match the sensitivity of the speakers and amplifiers. Recommended method: After each full filter (after LP650×2, MID-chain HP650×2 → LP2500×2, HP2500×2), install: A passive attenuator: Series: Rseries (0–10 kΩ, adjustable) Shunt: Rshunt to GND (10–22 kΩ, fixed or adjustable) For simplicity and reliability: Implementation on the board: For each band (LOW, MID, HIGH) provide: Pad for multi-turn trimmer 10–20 kΩ as a divider (between signal and ground) in the "level adjustment" configuration. If adjustment is not needed — install a fixed divider (two resistors) or simply use a jumper. It is preferable to use: For setup: multi-turn trimmers 10–20 kΩ, available on the top side of the board. Nominals for the initial configuration can be selected through measurements, but the PCB should have flexibility. This provides: Accurate balancing of band volumes without interfering with the filters; Flexibility for fine-tuning to the specific characteristics of the speakers. 8. INPUTS AND OUTPUTS OF THE CROSSOVER (FINAL) 8.1 Inputs 1× Unbalanced linear input (RCA or 3-pin header) 1× Balanced input (XLR/TRS or 3-pin header) — optional, but space must be provided on the board. Input impedance (unbalanced after RF-filter): 22–50 kΩ. The input tract must be implemented using shielded cables. 8.2 Outputs Outputs to amplifiers: Output Signal LOW OUT After LP650×2 (LF) MID OUT After HP650×2 → LP2500×2 (MF) HIGH OUT After HP2500×2 (HF) Each output: Series resistor 100–220 Ω (prevents possible oscillations and simplifies cable management). A nearby own AGND pad (ground output), so the signal pair SIG+GND runs together. Outputs should be compactly placed on 2-pin connectors (SIG+GND) or 3-pin (SIG+GND+reserve). 9. PCB DESIGN REQUIREMENTS 9.1 Board Number of layers: 2 layers Bottom layer: solid analog ground (AGND). 9.2 Component Placement Key principles: RC chains of each filter (R1, R2, C1, C2, Rf, Rg) should form a compact "island" around the corresponding op-amp. If elements are placed too far apart, the filter will not work correctly (calculated frequency and Q will shift). Feedback tracks (Rf and Rg) should be as short and direct as possible. The AM4T-4815DZ module should be placed: Far from the input buffer, Far from the first filter stages, If necessary, make a "cutout" in the ground under it to limit noise propagation. Place the input connector, RF-filter, and buffer on one side of the board, and the output connectors on the opposite side. 9.3 Ground The entire audio circuit uses one analog ground: AGND. Connect AGND to the power ground (48 V and amplifiers) at one point ("star"). The star should be implemented as: One point/pad where: The ground of the input, The ground of the filters, The ground of the outputs, The ground of the DC/DC. Avoid long narrow "ground" jumpers — use wide polygons with a single connection point. 9.4 Placement of Output Connectors Group LOW/MID/HIGH compactly. Each should have its own GND pad nearby. Route the SIG+GND pairs as signal pairs, avoiding large loops. 10. ADDITIONAL ELEMENTS: PROTECTION, TEST POINTS 10.1 Test Points (TP) Be sure to provide test points (pads): TP_IN — crossover input (after buffer) TP_LOW — LF filter output TP_MID — MF filter output TP_HIGH — HF filter output TP_+15, TP_–15, TP_GND — power control This greatly simplifies debugging with an oscilloscope. 10.2 Power Protection On the 48 V input — it is advisable to provide: Diode/scheme for reverse polarity protection (if possible), TVS diode or varistor for voltage spikes (optional). 10.3 Possible Stability Correction Pads for small capacitors (10–47 pF) in parallel with Rf in buffers and, if necessary, in some stages — in case of stability issues (this can be not installed in the first revision, but footprints should be provided). 11. BILL OF MATERIALS (BOM) Operational Amplifiers: NE5532 — 4 pcs (filters) NE5532 — 1–2 pcs (input buffer and balanced input) Total: 5–6 NE5532 packages. Resistors (1%, metal-film): 24.9 kΩ — 8 pcs 6.34 kΩ — 8 pcs 10 kΩ — ≥ 12 pcs (feedback, buffers, etc.) 5.9 kΩ — 8 pcs 22 kΩ — 1–2 pcs (input, auxiliary chains) 47–100 kΩ — several pcs (DC-block, input) 100 kΩ — 1 pc (if needed) 100–220 Ω — 4–6 pcs (outputs, RF, protection) 4.7–10 Ω — 2 pcs for each op-amp or group of op-amps (power filtering) — quantity to be clarified during routing. Trimmer Resistors: 10–20 kΩ multi-turn — one for each band (LOW, MID, HIGH) 10–20 kΩ — 1–2 pcs for the input buffer (overall gain adjustment). Capacitors: 10 nF film — 16 pcs (RC filters) 2.2–4.7 µF film — 1–2 pcs (input DC-block) 10–22 µF electrolytic — 2–4 pcs (DC/DC outputs) 1–4.7 µF (X7R / tantalum) — 1 pc for local power filtering (optional). 100 nF ceramic X7R — 10–20 pcs (local decoupling for each op-amp) 470–1000 pF — 1–2 pcs (RF filter on the input) 10–47 pF — optional for stability correction (Rf). Power Supply: AM4T-4815DZ — 1 pc Inductor 10–22 µH (if LC filter) — 1 pc R 1–2 Ω / 1–2 W — 1 pc (if RC filter). Connectors: Input (RCA + 3-pin for internal input) Balanced (XLR/TRS or 3-pin header) Outputs LOW/MID/HIGH — 2-pin/3-pin connectors. 12. TESTING RECOMMENDATIONS 12.1 First Power-up Apply ±15 V without installed op-amps. Check with a multimeter: +15 V –15 V No short circuits in the power supply. Install the op-amps (NE5532). Apply a sine wave of 100–200 mV RMS (signal generator). Check with an oscilloscope at TP: LP650 — should pass LF and roll off everything above 650 Hz. HP650 — should roll off LF, pass everything above 650 Hz. LP2500 — should roll off above 2500 Hz. **HP250 0** — should pass everything above 2500 Hz. 12.2 Phase Check The Linkwitz–Riley 4th order should give a flat frequency response when summed at the crossover points. This can be verified with REW/Arta. 12.3 Noise Check If there is noticeable "shshsh" or whistling: Check: Grounding layout (star) Placement and filtering of AM4T-4815DZ Presence and proper installation of all 100 nF and local filters. 13. FINAL RECOMMENDATIONS FOR BEGINNERS Do not rush, build the circuit step by step: input → buffer → one filter → test, then continue. Check component values at least twice before soldering. Filters should be routed as compact "islands" around the op-amp, do not stretch R and C across the board. Always remember the rule: "The feedback trace should be as short as physically possible." Before ordering the PCB, make a "paper prototype": print at 1:1, cut it out, place real components to check everything fits.

Adafruit 2.8 Inch ILI9341 240x320 SPI TFT LCD Display Touch Panel SPI Serial Port Module #display #lcd

This is a 16x2 LCD display screen with I2C interface. It is able to display 16x2 characters on 2 lines, white characters on blue background.

Welcome to your new project. Imagine what you can build here.

This is a 16x2 LCD display screen with I2C interface. It is able to display 16x2 characters on 2 lines, white characters on blue background.

Termómetro con Arduino Nano y LCD

This is a 16x2 LCD display screen with I2C interface. It is able to display 16x2 characters on 2 lines, white characters on blue background.