This project is an RF-ID lock circuit, complete with microcontroller (MCU). It features an RC522 RFID reader for identification, controlled by an STM32F103C8T6 MCU. The structure also includes an OLED display, lock circuit, and user interface switches. Designed to operate with a AAA battery power source. #MCU #referenceDesign #simple-embedded #stm #project #STM32 #lock #OLED #template #reference-design

This is a BLE to WiFi gateway Reference Design. It employs an ESP32 microcontroller and an STM32WB5MMGH6TR for BLE functionality. The design includes connectors, multiple capacitors, resistors, switches, and LEDs. USB Type-C is used for power and data. This could be used for IoT purposes in home automation or wireless sensor data transmission. #referenceDesign #edge-computing #espressif #stm #template #ble #reference-design

This project is an RF-ID lock circuit, complete with microcontroller (MCU). It features an RC522 RFID reader for identification, controlled by an STM32F103C8T6 MCU. The structure also includes an OLED display, lock circuit, and user interface switches. Designed to operate with a AAA battery power source. #MCU #referenceDesign #simple-embedded #stm #project #STM32 #lock #OLED #template #reference-design

This is a BLE to WiFi gateway Reference Design. It employs an ESP32 microcontroller and an STM32WB5MMGH6TR for BLE functionality. The design includes connectors, multiple capacitors, resistors, switches, and LEDs. USB Type-C is used for power and data. This could be used for IoT purposes in home automation or wireless sensor data transmission. #referenceDesign #edge-computing #espressif #stm #template #ble #reference-design

This is a BLE to WiFi gateway Reference Design. It employs an ESP32 microcontroller and an STM32WB5MMGH6TR for BLE functionality. The design includes connectors, multiple capacitors, resistors, switches, and LEDs. USB Type-C is used for power and data. This could be used for IoT purposes in home automation or wireless sensor data transmission. #referenceDesign #edge-computing #espressif #stm #template #ble #reference-design

This is a BLE to WiFi gateway Reference Design. It employs an ESP32 microcontroller and an STM32WB5MMGH6TR for BLE functionality. The design includes connectors, multiple capacitors, resistors, switches, and LEDs. USB Type-C is used for power and data. This could be used for IoT purposes in home automation or wireless sensor data transmission. #referenceDesign #edge-computing #espressif #stm #template #ble #reference-design

This project is an RFID lock circuit, complete with microcontroller (MCU). It features an RC522 RFID reader for identification, controlled by an STM32F103C8T6 MCU. The structure also includes an OLED display, lock circuit, and user interface switches. Designed to operate with a AAA battery power source. #MCU #referenceDesign #simpleEmbedded #stm #project #STM32 #lock #OLED #template #reference-design

This is a BLE to WiFi gateway Reference Design. It employs an ESP32 microcontroller and an STM32WB5MMGH6TR for BLE functionality. The design includes connectors, multiple capacitors, resistors, switches, and LEDs. USB Type-C is used for power and data. This could be used for IoT purposes in home automation or wireless sensor data transmission. #referenceDesign #edge-computing #espressif #stm #template #ble #reference-design

Simple plug-and-play breadboard power supply with current monitoring output, LED indicators, switches for both rails, and decoupling capacitors.

This project is an RF-ID lock circuit, complete with microcontroller (MCU). It features an RC522 RFID reader for identification, controlled by an STM32F103C8T6 MCU. The structure also includes an OLED display, lock circuit, and user interface switches. Designed to operate with a AAA battery power source. #MCU #referenceDesign #simple-embedded #stm #project #STM32 #lock #OLED #template #reference-design

This is a reference design of step-up dc-to-dc switching converter based ADP1613 with a 15V output #dcdc #power #boost #15V #referenceDesign #powermanagement #analogdevices #template #reference-design

The Sinopower APM2300CA is a high-performance N-Channel Enhancement Mode MOSFET designed for efficient power management applications in notebook computers, portable equipment, and battery-powered systems. This MOSFET offers a drain-source voltage (VDSS) of 20V and a continuous drain current (ID) of 6A, providing reliable and rugged performance. Featuring a low R_DS(on) of 25mΩ at V_GS=10V, 32mΩ at V_GS=4.5V, 40mΩ at V_GS=2.5V, and 65mΩ at V_GS=1.8V, the APM2300CA ensures minimal power loss and high efficiency. The component is housed in a compact SOT-23 package, making it suitable for space-constrained applications. With a maximum junction temperature of 150°C and compliance with RoHS and halogen-free standards, the APM2300CA is an environmentally friendly choice that does not sacrifice performance. Other notable features include low gate charge and fast switching capabilities, making it ideal for rapid and efficient power conversion tasks.

This is a reference design of step-up dc-to-dc switching converter based ADP1613 with a 15V output #dcdc #power #boost #15V #referenceDesign #powermanagement #analogdevices #template #reference-design

The inverter specs are Switching frequency: 200kHz Input voltage: 180VDC Output voltage: 120VAC Max power: 1500W I have designed an Inverter schematic for an uninterruptible power supply (UPS), Used an efficiency LCL topology filter to eliminate 3rd and 5th harmonics as induction motor is connected at load. The Inverter schematic that can convert 180VDC into 120VAC, which can be used in any household or industrial application. You can refer the BOM to check the MOSFET parts, drivers, and filter parameter values.

The inverter specs are Switching frequency: 200kHz Input voltage: 180VDC Output voltage: 120VAC Max power: 1500W I have designed an Inverter schematic for an uninterruptible power supply (UPS), Used an efficiency LCL topology filter to eliminate 3rd and 5th harmonics as induction motor is connected at load. The Inverter schematic that can convert 180VDC into 120VAC, which can be used in any household or industrial application. You can refer the BOM to check the MOSFET parts, drivers, and filter parameter values.

High-current 12V to 5V robot power distribution PCB with XT60 battery input, inline fuse protection, switched 12V rail, 5V/5A buck regulation, dedicated outputs for Raspberry Pi, sensors, USB hub, fan, and motor power distribution.

2-layer 75×66mm RED KOMODO-X power and IO distribution board with dual input ORing, protected switched bus, 3.3V logic rail, edge solder-pad flying-lead terminals, and split ground star-point architecture.

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

The DMN3016LFDF is an N-Channel Enhancement Mode MOSFET manufactured by Diodes Incorporated, designed for high-efficiency power management applications. This MOSFET features a low on-state resistance (RDS(ON)) of 12mΩ at VGS = 10V and 16mΩ at VGS = 4.5V, with a maximum drain current (ID) of 10A at TA = +25°C. The device operates with a drain-source voltage (BVDSS) of 30V and a gate-source voltage (VGSS) of +20V. It is ideally suited for battery management, power management functions, and DC-DC converters due to its superior switching performance and low gate threshold voltage. The component is housed in a U-DFN2020-6 (Type F) package with a 0.6mm profile, making it suitable for low-profile applications. It is also fully RoHS compliant, halogen and antimony-free, and qualified to JEDEC standards for high reliability.

This project is a WiFi Gesture Light Switch controlled by an ESP32 microcontroller. It leverages APDS-9960 and CH340C ICs for gesture recognition and USB communication respectively. Essential components include diodes for voltage protection, LEDs for status indication, and an AMS1117 voltage regulator to ensure a stable power supply. Connectors like USB Type-C are used for power and data transfers. #referenceDesign #project #ESP32 #ESP32WROOM #RF #WIFI #MCU #thermostat #referenceDesign #edge-computing #edgeComputing #espressif #template #reference-design

This project is a WiFi Gesture Light Switch controlled by an ESP32 microcontroller. It leverages APDS-9960 and CH340C ICs for gesture recognition and USB communication respectively. Essential components include diodes for voltage protection, LEDs for status indication, and an AMS1117 voltage regulator to ensure a stable power supply. Connectors like USB Type-C are used for power and data transfers. #referenceDesign #project #ESP32 #ESP32WROOM #RF #WIFI #MCU #thermostat #referenceDesign #edge-computing #edgeComputing #espressif #template #reference-design

This project is a WiFi Gesture Light Switch controlled by an ESP32 microcontroller. It leverages APDS-9960 and CH340C ICs for gesture recognition and USB communication respectively. Essential components include diodes for voltage protection, LEDs for status indication, and an AMS1117 voltage regulator to ensure a stable power supply. Connectors like USB Type-C are used for power and data transfers. #referenceDesign #project #ESP32 #ESP32WROOM #RF #WIFI #MCU #thermostat #referenceDesign #edge-computing #edgeComputing #espressif #template #reference-design

This project is a WiFi Gesture Light Switch controlled by an ESP32 microcontroller. It leverages APDS-9960 and CH340C ICs for gesture recognition and USB communication respectively. Essential components include diodes for voltage protection, LEDs for status indication, and an AMS1117 voltage regulator to ensure a stable power supply. Connectors like USB Type-C are used for power and data transfers. #referenceDesign #project #ESP32 #ESP32WROOM #RF #WIFI #MCU #thermostat #referenceDesign #edge-computing #edgeComputing #espressif #template #reference-design

The Alpha & Omega Semiconductor AO3422 is a high-performance, N-channel enhancement mode field effect transistor (FET) designed using advanced trench technology. This technology ensures the component offers low RDS(ON) and minimal gate charge, making it highly efficient for use in various electronic applications. Key features of the AO3422 include a 55V drain-source voltage (VDS), a continuous drain current (ID) of 2.1A at a gate-source voltage (VGS) of 4.5V, and RDS(ON) values as low as 160mΩ at VGS = 4.5V. It supports a wide gate drive range from 2.5V to 12V, making it versatile for different operating conditions. Specifically designed for load switch applications, the AO3422 comes in a compact SOT23 package, offering a blend of performance, efficiency, and space-saving design. Its absolute maximum ratings include a drain-source voltage of up to 55V, gate-source voltage of up to +12V, and a power dissipation of 1.25W at 25°C. With thermal characteristics designed for robust operation, including a maximum junction-to-ambient thermal resistance of 75°C/W for short durations, the AO3422 is optimized for high-performance switch operations in a range of electronic circuits.

This project is a WiFi Gesture Light Switch controlled by an ESP32 microcontroller. It leverages APDS-9960 and CH340C ICs for gesture recognition and USB communication respectively. Essential components include diodes for voltage protection, LEDs for status indication, and an AMS1117 voltage regulator to ensure a stable power supply. Connectors like USB Type-C are used for power and data transfers. #referenceDesign #project #ESP32 #ESP32WROOM #RF #WIFI #MCU #thermostat #referenceDesign #edge-computing #edgeComputing #espressif #template #reference-design

This project is a WiFi Gesture Light Switch controlled by an ESP32 microcontroller. It leverages APDS-9960 and CH340C ICs for gesture recognition and USB communication respectively. Essential components include diodes for voltage protection, LEDs for status indication, and an AMS1117 voltage regulator to ensure a stable power supply. Connectors like USB Type-C are used for power and data transfers. #referenceDesign #project #ESP32 #ESP32WROOM #RF #WIFI #MCU #thermostat #referenceDesign #edge-computing #edgeComputing #espressif #template #reference-design

This project is a WiFi Gesture Light Switch controlled by an ESP32 microcontroller. It leverages APDS-9960 and CH340C ICs for gesture recognition and USB communication respectively. Essential components include diodes for voltage protection, LEDs for status indication, and an AMS1117 voltage regulator to ensure a stable power supply. Connectors like USB Type-C are used for power and data transfers. #referenceDesign #project #ESP32 #ESP32WROOM #RF #WIFI #MCU #thermostat #referenceDesign #edge-computing #edgeComputing #espressif #template #reference-design

This project is a WiFi Gesture Light Switch controlled by an ESP32 microcontroller. It leverages APDS-9960 and CH340C ICs for gesture recognition and USB communication respectively. Essential components include diodes for voltage protection, LEDs for status indication, and an AMS1117 voltage regulator to ensure a stable power supply. Connectors like USB Type-C are used for power and data transfers. #referenceDesign #project #ESP32 #ESP32WROOM #RF #WIFI #MCU #thermostat #referenceDesign #edge-computing #edgeComputing #espressif #template #reference-design

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.

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.

Circuit Overview The circuit you're describing is a digital counter that uses an LDR (Light-Dependent Resistor) and a transistor to detect wheel rotations. The counter's output is then displayed on a seven-segment LED display. Here's a breakdown of the components and their roles: 1. Wheel Rotation Detection (LDR and Transistor) * LDR: The LDR acts as a sensor to detect changes in light intensity. You can mount it on the wheel' or near it, with a reflective or non-reflective surface attached to the wheel. As the wheel rotates, the LDR will be exposed to alternating light and dark conditions, causing its resistance to change. * Transistor: The transistor (e.g., a 2N2222 NPN BJT) is used as a switch or amplifier. The changing resistance of the LDR is used to control the base current of the transistor. When the LDR's resistance drops (more light), the transistor turns on, and when the resistance increases (less light), the transistor turns off. This converts the analog change in light into a digital ON/OFF signal (a pulse). 2. Counter (7490) * 7490 IC: This is a decade counter, meaning it can count from 0 to 9. The output of the transistor (the pulses) is fed into the clock input of the 7490. Each pulse represents one rotation of the wheel, and the 7490 increments its count accordingly. The 7490 has four outputs (Q0, Q1, Q2, Q3) that represent the BCD (Binary-Coded Decimal) equivalent of the count. 3. BCD to Seven-Segment Decoder (7446) * 7446 IC: The 7446 is a BCD-to-seven-segment decoder/driver. Its job is to take the 4-bit BCD output from the 7490 and convert it into a signal that can drive a seven-segment LED display. It has seven outputs (a, b, c, d, e, f, g), each corresponding to a segment of the LED display. 4. Seven-Segment LED Display * Seven-Segment Display: This display is used to show the count. The 7446's outputs are connected to the corresponding segments of the display. 5. Power Supply and Other Components * Power Supply: A regulated DC power supply (e.g., 5V) is needed to power all the ICs and components. * Resistors: Resistors are used for current limiting (e.g., for the LDR and the LED display) and biasing the transistor. * Capacitors: A capacitor might be used for debouncing the signal from the transistor to prevent multiple counts for a single rotation. Conceptual Connections Here is a step-by-step breakdown of how the components would be connected: * LDR and Transistor: * The LDR and a current-limiting resistor are connected in series across the power supply. * The junction between the LDR and the resistor is connected to the base of the NPN transistor. * The emitter of the transistor is connected to ground. * The collector of the transistor, with a pull-up resistor, becomes the output for the pulse signal. * Transistor to 7490: * The output from the transistor's collector is connected to the clock input of the 7490 IC. * The 7490's reset pins (MR and MS) should be connected to ground for normal counting operation. * 7490 to 7446: * The BCD outputs of the 7490 (Q0, Q1, Q2, Q3) are connected to the BCD inputs of the 7446 (A, B, C, D). * 7446 to Seven-Segment Display: * The outputs of the 7446 (a, b, c, d, e, f, g) are connected to the corresponding segments of the seven-segment display. * Crucially, you need to use current-limiting resistors (e.g., 330Ω) in series with each segment to protect the LEDs from high current. * The common terminal of the seven-segment display is connected to the power supply (for a common anode display) or ground (for a common cathode display). This setup creates a chain reaction: wheel rotation changes light, which changes LDR resistance, which turns the transistor on/off, generating a pulse. This pulse increments the 7490, and the 7490's output is decoded by the 7446, which then displays the count on the seven-segment LED.

This project is a WiFi Gesture Light Switch controlled by an ESP32 microcontroller. It leverages APDS-9960 and CH340C ICs for gesture recognition and USB communication respectively. Essential components include diodes for voltage protection, LEDs for status indication, and an AMS1117 voltage regulator to ensure a stable power supply. Connectors like USB Type-C are used for power and data transfers. #referenceDesign #project #ESP32 #ESP32WROOM #RF #WIFI #MCU #thermostat #referenceDesign #edge-computing #edgeComputing #espressif #template #reference-design

The AO3414, manufactured by Alpha & Omega Semiconductor, is an N-Channel Enhancement Mode Field Effect Transistor (FET) designed using advanced trench technology to deliver superior RDS(ON), low gate charge, and operation with gate voltages as low as 1.8V. Ideal for load switch and PWM applications, the AO3414 is available in a Pb-free version that complies with ROHS and Sony 259 specifications, and a Green Product variant (AO3414L), both of which are electrically identical. Key specifications include a drain-source voltage (VDS) of 20V, a continuous drain current (ID) of 4.2A at VGS=4.5V, and a maximum RDS(ON) of 50mΩ at VGS=4.5V. The device is housed in a TO-236 (SOT-23) package, ensuring compact and efficient thermal performance. Additionally, the AO3414 boasts a maximum power dissipation of 1.4W at TA=25°C, a gate-source voltage (VGS) rating of +8V, and an operating junction temperature range of -55°C to 150°C. This component is optimized for consumer market applications, offering reliable performance and compliance with environmental standards.

The PAN JIT SEMICONDUCTOR PJC831K is a 50V N-Channel Enhancement Mode MOSFET designed for switch load and PWM applications, with added ESD protection up to 2KV HBM. Utilizing advanced trench process technology, it offers low RDS(on) values of <1.60Ω at VGS=10V, <2.50Ω at VGS=4.5V, and <4.50Ω at VGS=2.5V. The component is capable of handling a continuous drain current of 360 mA and a pulsed drain current of up to 1200 mA, constrained by a maximum power dissipation of 236 mW at 25°C. The MOSFET is housed in a SOT-323 package with excellent thermal resistance characteristics (530°C/W junction to ambient). It meets RoHS 2.0 compliance and IEC 61249 standards with a green molding compound. Featuring minimal gate charge and fast switching times, this MOSFET is optimized for efficiency and reliability in demanding applications.

Cyberdeck power distribution hub using a TP4056 Type-C Li-ion charger module, MT3608 boost converter module, switched output rail, voltmeter, servo, Arduino VIN, button signal header, and battery terminal on a 50 mm × 70 mm PCB.

The Pico Macro Keyboard is a compact and powerful macro pad built using the latest Raspberry Pi Pico 2. Inspired by the Figma Creator Micro, this keyboard is designed for customizable control and enhanced productivity. It features mechanical switches with per-key RGB lighting, along with two rotary encoders for added functionality. With a modular 4-layer PCB and fully customizable keymaps, it seamlessly integrates with any software, making it perfect for designers, gamers, and power users alike.

The APM2300CA, manufactured by Sinopower Semiconductor, is a high-performance N-Channel Enhancement Mode MOSFET designed for power management in notebook computers, portable equipment, and battery-powered systems. This component delivers a maximum drain-source voltage (VDSS) of 20V and can handle continuous drain current up to 6A when VGS is 10V, ensuring robust performance for demanding applications. Its low RDS(ON) values of 25mΩ (typ.) at VGS=10V, 32mΩ (typ.) at VGS=4.5V, 40mΩ (typ.) at VGS=2.5V, and 65mΩ (typ.) at VGS=1.8V minimize power loss and heat generation. The APM2300CA is reliable and rugged, complying with RoHS standards and available in a lead-free, halogen-free SOT-23 package, featuring a maximum power dissipation of 0.83W at 25℃. It is optimized for fast switching, with total gate charge (Qg) of 6nC (typ.) at VGS=4.5V and a gate resistance (RG) of 6Ω, supporting efficient and precise control in diverse power applications.

Buck Converter Input Voltage: 220VAC Input Power: 30W AC Frequency : 50/60Hz Power Factor: 0.5 LED Output Voltage: 160V LED Output Current: 170mA Driver Efficiency : 93% Switching Frequency : 200kHz Output Current after diode bridge rectifier : 100mA Output Voltage after diode bridge rectifier : 310VDC

This circuit is an ultrasonic distance meter based on an ATTiny2313 microcontroller. It uses an HC-SR04 ultrasonic sensor to measure distance and displays the results on an OLED display. The power supply is constructed using a Boost converter (TPS613222A) and a 2-cell AA battery. Additionally, it also includes ISP for programming, RESET and START switches, and LED indicators. #project #Template #projectTemplate #ultrasonic #OLED #arduino #attiny2313 #TPS613222A #ISP #referenceDesign #simple-embedded #microchip #template #reference-design

The Coffee Waker is a unique, full-featured coffee maker alarm clock designed to brighten your morning routine with the irresistible aroma of freshly brewed coffee. By seamlessly integrating multiple high-performance components onto a single main board, the Coffee Waker delivers both functionality and innovation: - **Processing & Connectivity:** Powered by an ESP32-S3, it offers built-in WiFi and Bluetooth, enabling smart scheduling, remote control, and over-the-air updates. - **Precision Sensing:** A 16-bit load cell ADC provides accurate measurements, ensuring precise weight sensing for coffee bean dosing or liquid volume monitoring. - **Quality Audio Output:** The onboard 16-bit MP3 DAC guarantees clear audio playback, from alarm sounds to any custom wake-up messages you program. - **Robust Power Handling:** With a 120V heater cartridge relay and a 12V wakeup light converter integrated, the board safely manages high voltage switching and provides a visually soothing light routine. - **Thoughtful Integration:** Designed with automotive-grade components, precision regulators, and careful signal routing, the Coffee Waker Main Board combines performance with reliability while keeping a compact footprint. Overall, the Coffee Waker transcends the ordinary alarm clock, merging daily utility with modern connectivity and a touch of luxury—making it the perfect addition to any nightstand. #CoffeeWaker #SmartHome #CoffeeMaker #AlarmClock #MorningRoutine #Technology #Innovation

This circuit is an ultrasonic distance meter based on an ATTiny2313 microcontroller. It uses an HC-SR04 ultrasonic sensor to measure distance and displays the results on an OLED display. The power supply is constructed using a Boost converter (TPS613222A) and a 2-cell AA battery. Additionally, it also includes ISP for programming, RESET and START switches, and LED indicators. #project #Template #projectTemplate #ultrasonic #OLED #arduino #attiny2313 #TPS613222A #ISP #referenceDesign #simple-embedded #microchip #template #reference-design

This circuit is an ultrasonic distance meter based on an ATTiny2313 microcontroller. It uses an HC-SR04 ultrasonic sensor to measure distance and displays the results on an OLED display. The power supply is constructed using a Boost converter (TPS613222A) and a 2-cell AA battery. Additionally, it also includes ISP for programming, RESET and START switches, and LED indicators. #project #Template #projectTemplate #ultrasonic #OLED #arduino #attiny2313 #TPS613222A #ISP #referenceDesign #simple-embedded #microchip #template #reference-design

This circuit is an ultrasonic distance meter based on an ATTiny2313 microcontroller. It uses an HC-SR04 ultrasonic sensor to measure distance and displays the results on an OLED display. The power supply is constructed using a Boost converter (TPS613222A) and a 2-cell AA battery. Additionally, it also includes ISP for programming, RESET and START switches, and LED indicators. #project #Template #projectTemplate #ultrasonic #OLED #arduino #attiny2313 #TPS613222A #ISP #referenceDesign #simple-embedded #microchip #template #reference-design

This is a schematic of an IR (infrared) remote control system. It's built around a Microchip ATTINY2313 microcontroller (U1) and boasts five push-button switches, an indicator RED LED and an electret buzzer for user interaction. An ISP header provides programming capabilities. The project is battery-powered and implements boost converter TPS613222AD (IC1) for stable power supply. #project #Template #projectTemplate #lock #keypad #attiny2313 #TPS613222A #ISP #buzzer #reusable #module #simple-embedded #microchip #arduino #sublayout

This is a schematic of an IR (infrared) remote control system. It's built around a Microchip ATTINY2313 microcontroller (U1) and boasts five push-button switches, an indicator RED LED and an electret buzzer for user interaction. An ISP header provides programming capabilities. The project is battery-powered and implements boost converter TPS613222AD (IC1) for stable power supply. #project #Template #projectTemplate #lock #keypad #arduino #attiny2313 #TPS613222A #ISP #buzzer #referenceDesign #simple-embedded #microchip #template #reference-design

The J175, J176, MMBFJ175, MMBFJ176, and MMBFJ177 are a series of P-Channel switches designed and manufactured by onsemi™, suitable for low-level analog switching, sample-and-hold circuits, and chopper-stabilized amplifiers. These components are sourced from process 88, indicating a specific manufacturing technique employed by onsemi™ to ensure consistent performance and reliability. The devices are offered in both TO-92 and SOT-23 packages, catering to a variety of mounting preferences and application requirements. They are characterized by their ability to handle a drain-gate voltage of -30V, a gate-source voltage of 30V, and a forward gate current of 50 mA. Operating and storage junction temperature ranges are specified from -55 to +150°C, ensuring robustness across a wide range of environmental conditions. With features like low on-resistance and high transconductance, these components are optimized for efficient signal modulation and minimal power loss, making them highly suitable for precision applications in analog signal processing.

This circuit is an ultrasonic distance meter based on an ATTiny2313 microcontroller. It uses an HC-SR04 ultrasonic sensor to measure distance and displays the results on an OLED display. The power supply is constructed using a Boost converter (TPS613222A) and a 2-cell AA battery. Additionally, it also includes ISP for programming, RESET and START switches, and LED indicators. #project #Template #projectTemplate #ultrasonic #OLED #arduino #attiny2313 #TPS613222A #ISP #reusable #module #simple-embedded #microchip #sublayout

The Pico Macro Keyboard is a compact and powerful macro pad built using the latest Raspberry Pi Pico 2. Inspired by the Figma Creator Micro, this keyboard is designed for customizable control and enhanced productivity. It features mechanical switches with per-key RGB lighting, along with two rotary encoders for added functionality. With a modular 4-layer PCB and fully customizable keymaps, it seamlessly integrates with any software, making it perfect for designers, gamers, and power users alike.

The Pico Macro Keyboard is a compact and powerful macro pad built using the latest Raspberry Pi Pico 2. Inspired by the Figma Creator Micro, this keyboard is designed for customizable control and enhanced productivity. It features mechanical switches with per-key RGB lighting, along with two rotary encoders for added functionality. With a modular 4-layer PCB and fully customizable keymaps, it seamlessly integrates with any software, making it perfect for designers, gamers, and power users alike.

The Pico Macro Keyboard is a compact and powerful macro pad built using the latest Raspberry Pi Pico 2. Inspired by the Figma Creator Micro, this keyboard is designed for customizable control and enhanced productivity. It features mechanical switches with per-key RGB lighting, along with two rotary encoders for added functionality. With a modular 4-layer PCB and fully customizable keymaps, it seamlessly integrates with any software, making it perfect for designers, gamers, and power users alike.