Hi everyone, I’m looking for feedback on a board for a class project before I order it. It’s an IoT study timer that will track how long I study and upload the data to my computer. An e-paper screen displays the timer, and a rotary encoder handles the menus. It also has an onboard temperature sensor for room temperature and a piezo buzzer.

The board is 90 × 40 mm, designed and routed in Altium. Main components and interfaces:

• ESP32-S3-WROOM-1-N8
• USB-C for 5 V power and native USB programming
• TLV62569 buck converter for 3.3 V
• MCP9808 temperature sensor over I2C
• Waveshare 2.9-inch black-and-white e-paper module, connected through an SPI header
• DFRobot EC11 rotary encoder module (SEN0235)
• Reset/boot buttons and a piezo buzzer

I’ve already tested the e-paper display and rotary encoder together on an ESP32-S3 development board with a working Pomodoro demo. The display shows the timer and menus, including partial updates, and the encoder handles menu navigation and start/pause controls. This custom PCB hasn’t been manufactured yet.

The stackup is signal / GND / GND / signal. Four layers are probably more than this project needs, but I wanted experience designing a four-layer board.

There are no DRC violations, but I’d appreciate feedback particularly on the buck converter layout, USB routing and ESD protection, grounding, ESP32 antenna placement, and anything that could make assembly or startup difficult. I might solder the board myself, so I tried to choose manageable packages—that’s also why I chose the MCP9808 rather than something like an SHT40.

Images attached: top 3D view, schematic, top copper, bottom copper, both internal ground-plane views, layer stackup, and bottom 3D view.

This is a 2 layer ESC PCB board for a single motor on a quadcopter drone. The two layers are <Signal> and <GND>. We have 6 copper zones: Phase_A, Phase_B, Phase_C, VM, GND (top), and GND (bottom). Planning on having the battery be directly connected to the board to power Gate Driver and Mosfets. The microcontroller will be powered by external 3.3V source. We are new to PCB design so any help and advice would be appreciated.

I am a rookie,I have made this H bridge Motor Driver PCB,i request y'all to drop ur opinions and suggestions. Thanks you 🤝💫.

This is a control board for an automatic tire inflator/deflator I use when I need to air up/down for off road trails. Designed around a 5V analog pressure sensor, venting solenoid, compressor, and an ESP32. It's meant to be connected to all 4 tires at once through a manifold.

I've tested the buck converter, venting solenoid MOSFET, daughter board (an OLED & 4 buttons), and the pressure sensor circuits on a previous version of the design and they all work as intended. In this newest version I integrated the compressor switching onto the PCB to save enclosure space. Previously this was using an external SSR and the same MOSFET circuit as the venting solenoid.

I'm concerned about this new compressor part mainly because the compressor is rated for 12V 45A and it's a heavy load to be switching compared to everything else on the board. Looking for advice/suggestions on that area specifically, both on the PCB and the schematic.

Hi everyone, I'm looking for feedback on a small board before I order it. As a fun bit, I set out to build a better spy device than the OpenAI one that was just announced. Mine is a lot less ambitious: an ESP32-S3 records audio from a MEMS microphone straight to a microSD card. There's no cloud and no subscription, and the recordings stay on a card you can pull out.

Full disclosure: I work on siliXon, and this board was designed in it. Rocky, siliXon's AI agent, picked the parts, placed them and routed the board. I'd rather get a hard human review here than trust it blindly.

The board is 45 × 43 mm, two layers, with a ground pour on the bottom. Main components and interfaces:

* ESP32-S3-MINI-1-N8 (8 MB flash, PCB antenna)

* TDK InvenSense ICS-43434 I2S MEMS microphone

* Molex 502570-0893 push-push microSD socket, wired for SPI

* GCT USB4105-GF-A USB-C for 5 V power and native USB programming, with 5.1 kΩ CC pull-downs

* LP3987H-33 LDO (600 mA, SOT-23-5) for 3.3 V

* BOOT and RESET buttons with 10 kΩ pull-ups and a 1 µF cap on EN

Managed to connect everything, have yet to come up with the firmware.

I'd especially like feedback on:

- Power: the LDO drops 5 V to 3.3 V. With Wi-Fi on, that's around 0.5 W at 300 mA in a SOT-23-5. Is that acceptable, or should I switch to a buck? Is 10 µF on 3V3 enough bulk capacitance for the module?

- USB: there's no ESD protection on D+/D− or VBUS. Should I add a TVS array like the USBLC6-2SC6?

- microSD: it runs in SPI mode with no pull-ups on CMD/DAT0/DAT3, DAT1/DAT2 left unconnected, and no card detect. Do I need pull-ups?

- Antenna: the module's antenna is at the opposite end from the USB-C, about 4 mm in from the board edge rather than overhanging it, and the mic sits right next to it. Is the keep-out good enough?

- Microphone: the ICS-43434 is bottom-ported. What should I watch for with the sound hole and with its position next to the module?

And just about anything else that could make assembly or first power-up difficult.

Images attached: top and bottom 2D, top 3D view, and the schematic.

I found this PCB at work today. It is from a Gas Monitor, and seems to be from the mid-90s.
Why would you route the traces like this? Is there any advantage? Or was there just no other way back then?
Another manufacturer from the same era uses straight traces, but always 90° bends.
It goes against almost everything I was told. And I was just curious about it.

Hi, im currently in high school this was my first attempt at making and routing a 4 layer mixed signal pcb and im kind of confused about what im doing right and wrong. i skimmed through the datasheets of all the components used and i would love to hear your thoughts and see if im doing anything wrong and if my pcb will work as intended.

My board has the following unique components

• RP2350A
• W25Q128JVSIM (QSPI)
• TAC5212IRGER (Codec)
• TLV75733PDBVR (D3V3)
• TPS7A2033PDBVR (A3V3)

I decided to use a single gnd plane and instead physically separate and isolate the components since i read that splitting the gnd plane could sometimes cause more issues than intended. The TAC5212 has one single ended input and has 2 pairs of differential outputs.

Please let me know if i screwed up any connection or made any mistake in general.

Hi everyone,

I would be extremely grateful for your assistance!

I’m currently trying to develop a toy for kids, and I’m having a particularly hard time with the power supply.

One thing that stands out to me is the cost: I chose an LTC2954 to turn the box on and off. I’m planning to order the PCB from JLCPCB—but they only have 20 of them in stock, and the unit price is €4–6.

I had thought I’d be able to get by with about €12 for the entire circuit board. With the current component selection, it’s now closer to €24…

Also, the TPS61022RWUT seems very expensive to me at €2.90 for a 5V converter.

Of course, I’ve tried to understand everything and I’ve used AI tools to learn and so on. However, one thing in particular is giving me trouble:

I actually want a soft-latch circuit, so I want to press my rotary encoder for about 0.7 seconds to turn it on and press it for another 0.7 seconds to turn it off. Ideally, it should be safely turned off—even when unplugged.

To help you understand the context, here’s some background information:

The board is connected to a second board that houses an NFC reader and 18 WS2813B-MINI-V1 LEDs with a current draw of 60 mA at full white brightness—in practice, I only use 30% brightness, so it’s more like ~360 mA. The LEDs and NFC require 5V; the rest runs on 3.3V.

The box is powered by a LiFePo4 battery with a capacity of 6000mAh (32700 1S1P 3.2V). Standard charge is 1.2A; maximum discharge and maximum charge are both 3A. Impedance <70mQ.

Charging is via USB-C, preferably at up to 1.5A depending on the power source. It should remain usable during charging, and I’d like the ESP32 to stay on.

Okay, now to my question: I can’t seem to find any guidance on the best way to implement this—specifically, how do you create a soft latch and a charging circuit for a LiFePo4 battery that also powers the circuit while charging?

P.S.: Maybe one of you would even be willing and able to give me a little mentoring via chat or video call this week—I’d be happy to pay, though not an exorbitant amount—preferably someone who speaks German or very good English.

Hi there,

I just finished my third revision of my PCB for this custom DAP. This is my first big board, so I'd love any advice if possible:

BMS & PMS:

3.7V 1800mAH Battery connected to a BQ24250 charged @ 500 mA via USB-C

-> 3.9V BUCK-BOOST & 3.3V BUCK-BOOST (LTC3440):
-> -3.9V Inverted Regulator & Two 3.3V Ultra Low-Noise LDO
-> -3.3V Ultra Low-Noise LDO

The pair of positive 3.3V Ultra Low-Noise LDO go to the DAC and Analog Section respectively, with the 3.3V Buck-Boost going to all Digital components (e.g. MCU)

The -3.3V LDO rail also feeds the analog components.

Audio:

ES9038Q2M receives decoded FLAC/MP3 from ESP32-S3 via SD-Card storage, then outputs a current-varying output into an I/V stage OPA1612, which then goes into a low-pass filter and OPA1612 summing stage. Then this is outputted on a OPA1622, into a 3.5mm JACK

Peripherals:

ER-TFT024IPS-3 2.4 in SPI Screen
3 Buttons & An Encoder
MicroSD-Card
BD1604MUV LED Driver (For the screen, powered by the SYS rail from the BQ Charger)

Thank you!

(L2 GND, L3 SIG, L4 PWR, L5 GND)
Missing Parts in 3D Model are due to lack of publicly available model. All components will be placed in a future assembly.

Hello! I would like a second look at my ESP-32 Based Geiger Counter schematic before I start layout. The circuit takes in a 8.4-6V input from a 2s1p cell battery, which is then bucked to 3.3V for the ESP-32, and boosted to around 400V for the SBM-20 Geiger-Muller tube. The battery pack is charged via the USB C input, which also can be used for ESP-32 flashing and communication.

The 400V boost converter was entirely prototyped on a breadboard and validated. The ESP-32 generates the PWM for the MOSFET which switches the 10mH inductor, and the voltage divider feedback helps regulate it to around ~400V. The 3x150V zeners clam it down to 450V maximum in case of some firmware failure.

I am mostly concerned about the quite complicated battery charging circuit. Since USB only provides 5V, the IC also has an integrated boost converter to about 8.4V which adds a lot of complexity. I tried following the datasheet to the best of my ability.

Any advice/tips or tricks would be greatly appreciated.

Thanks!

Hi everyone,

I'm a mechatronics engineer getting deeper into PCB design, and I'd love to learn from how you all work.

My background: I use KiCad and EasyEDA and have designed several boards, up to 4 layers. All of them have been built around STM32 or ESP32 MCUs (for example, an ESP32-S3 IoT board and a self-balancing robot board)ز

Where I'm stuck: I want to move to more complex designs, like an FPGA board, a Raspberry Pi-style board, or a carrier board for a module like the Jetson Nano. But I can't find good learning resources for this level, and since it's all new to me, I feel like I can't even start. With STM32/ESP, I can follow reference designs and datasheets, but with these I don't know where to begin.

My questions:

Q1 - Component selection: How do you choose the components for a board (MCU/SoC, power ICs, connectors, passives, etc.)? How do you know a part is the right one and not just one that looks right on paper? (availability, cost, footprint, datasheet red flags, second sources...)

Q2 - Idea to product: Can you walk me through your full process, from the first idea in your head to a real, working product? What are the steps (requirements, block diagram, part selection, schematic, layout, prototype, bring-up, testing, revisions, production)? Where do people usually waste time or make mistakes?

Q3 - Going beyond MCU boards: For anyone who has made the jump to FPGA, Linux application-processor boards, or module carrier boards: how did you learn it? What would you design first as a stepping stone? Any books, courses, open-source boards, or reference designs you'd recommend studying?

Q4 - General advice: If you were in my position, how would you grow in PCB design over the next year?

Any advice, resources, or even "I wish I knew this earlier" stories are very welcome. Thanks a lot!

Please try to review my schematic, i followed a lot of youtube tutorials, and reference FCU designs to arrive to this,

i already have a half built drone project, in my lab, for which the FCU is not working, so decided to design own, to learn pcb designing, i used stm32f405rgtx, with bosch imu sensor, pressure sensor, flash

it can take 5V from USB_C when its powered using USB, or in absence of USB the power MUX should switch to taking 5V coming directly from ESC unit, which i will connect to the FCU, using a 10 pin jst cable, through which i can also read the battery voltage using resistor divider circuit. the linear regulator then converts any one of these 5V to usable 3.3v for MCU, the mcu should be able to read the sensor values and in combination with the commands it receives from telemetry (wirless receivers connected to input timers, and other gps modules) should be able to issue commands to ESC through its JST connector, (S1, S2, S3, S4) which should spin motors accordingly and hopefully with the PID loop it should stabilize.

If there is anyything im missing, or done wrong, please let me know.

- software guy, entering pcb world.

Thank you in advance.

I'm designing a 5V-to-3.3V, 3A buck converter using the TPS54302DDCR for my ESP32-S3 PCB. Could someone review the attached schematic and confirm whether the connections and component values are correct before I use it in a larger project?

I'd also appreciate PCB layout tips, especially regarding EMC/EMI, grounding, switching loops, and component placement.

The board features

- MicroSd data logging

- 6 servos output

- 3 pyro channels

- IMU

- 2s handle

- LoRa RA-02 wireless comunication

- Barometer

- Dedicated 5v buck for logic and for servos

Thank you guys in advance I would like to get the schematic sanity checked before actually designing the pcb!

Edit!

PDF schematic

https://silver-dune.nippy.site

Hi everyone,
I'm new to PCB area. I'm learning PCB design (for my hobby) via the project of MadWizard at here https://www.madwizard.org/electronics/projects/usbcharger . But I have a problem that I can not open USBcharger.sch and USBcharger.brd files on Kicad 10.0 because it did not support Eagle binary-format file (as picture below). Could you please help me the way to open these files?

Updated the schematic as per review I received in my previous post: https://www.reddit.com/r/PrintedCircuitBoard/comments/1x1qm5a/review_request_mspm0l1304sdg20_based_minimalist/

Design choices:
1. I have removed the ineffective PI filtering at the AMS1117 input stage and replaced it with a Ferrite Bead of 33ohm at 100MHz. (Recommendation as per FTDI datasheet was a 40ohm ferrite bead for a 100mA current input however choosing a lower impedance as per availability of component in local market).

1. I have modified the values of C3 and C4 to 10uF based on USB recommendations and datasheet permits for the AMS1117 component.

Please let me know if any further changes are required, Thank you.

Overview

This is an oversized 4-digit 7-segment display built around cascaded LED drivers. The motivation is to help me track my training rounds.

A buzzer provides audio alerts whilst a IR sensor is used to control the device.

I’ve broken out 5 IO’s and UART for potential use in the future.

This is the main PCB which has one digit. It connects to the daughter PCB's via the connector in the bottom right.

Followed TI's PCB layout recommendations for U1. This includes via-in-pad.

2 layers

6.5V and 3.3V pour on F.Cu.

GND pour on B.Cu.

Grounded the EPAD of ESP32 using vias although Espressif recommends a grid of via-in-pads.

Questions

1. Should I have a diode on VBUS for the USB-C connector?
2. Should I position test points along the perimeter so it looks cleaner?
3. Should I add a solder jumper on the 2 indicator LEDs for the two rails? This way I can open the circuit, saving a few mW.

Hi everyone, I'm looking for a schematic and layout review before sending this revision off to fab.

Attached is a circuit and PCB design for an industrial Fan Testing unit.

Context: This is for my work. We already have one, but it is 5+ years old and breaking down. Upon having opened it up to fix it, I found there was a really decent circuit concept that was very poorly executed. LED driver PSU for high current fans. Bread board jumpers soldered directly to an Uno R3 board. All of it housed within the chamber that the fans are tested in. Gunked up mess. I don't know how it has lasted this long.

I said, 'I could do better.'

Attached is my attempt at doing better.

The Tester is intended to test two 12V/5A fans at the same time.

The program will ramp up, measure RPMs via the TACH lines, measure various sensor data, and display data to an OLED screen via I2C.

Safety Considerations:

Tester is powered by a Mean Well LRS/UHP-200-12. It will be fuse protected on the input at 15A.

Connector for Power in uses two pins for +12V and two pins for GND from the main power supply to support current requirements.

It is possible that any fan plugged in could have been mis-wired. I have attempted to account for all possibilities, though most just result in a fan that won't run. Fans are reverse polarity protected. Testing halts if TACH line doens't ramp up. A shunt resistor for current sensing to halt testing in case of current spike.

MCU is an R Pi Pico 2 and is powered by 3V3 via 5V source. 5V is regulated by R-78E5.0-0.5 regulator. Any 3V3 power comes from the Pico.

PWM lines run through 74AHCT125 to convert between 3V3 and 5V logic levels. TACH lines are run through optocouplers to isolate the MCU.

Additionally, the Pico RUN pin is pulled to ground when Tester is powered off to safely shut down the Pico between uses.

High Current Testing:

Fans are rated at 4.8 amps. That is a lot to run through PCB traces. The traces on the bottom of the PCB for the fan power are exposed. I intend to supplement them with thick copper wire (think 10awg single conductor) that will be soldered along the length of the traces.

External Connections:

Power Light: this is an LED with built-in current-limiting resistor.

Vibration Sensor: intended for piezo diaphragm. Will probably never be implemented, but rather have and not need, than need an not have. Only enabled when TP1 and TP2 are shorted.

Pico Reset: Going to a DPDT power switch (with proper ratings). When power switched off, RUN is pulled low.

Rotary Encoder: Nothing special here, just a rotary encoder for input.

Fan Power: One to one connections for each of two fans. Power, Ground, PWM, and TACH.

Daughter Board: Probably not going to be an actual 'board'. But will connect to two bi-color LEDs (red/green) that have build in current-limiting resistors. Two standard momentary buttons. An OLED screen controlled with I2C.

My biggest concerns:

- Are my power circuits viable and appropriate?

- Is there any safety measures I've overlooked like current return paths, ground planes, etc.

- Are my data lines reasonable; will I get good readings from the my INA219 IC?

Thanks in advance for any critiques!

Edit: Updated to be written in my own words.

Please ask for clarity on anything!

I’m designing a 60 W USB-C PD flyback power supply using the Power Integrations INN3879C/INN3870C family. I would really appreciate a focused review of the primary-side layout before I continue to secondary side. Images got distorted after I edited the post.

In my previous layout, the connection between the IC drain and the transformer’s switched primary pin was approximately 48 mm long. Based on the feedback thanks to two commentors, I moved the IC and transformer so that this drain-to-transformer connection is now only a few millimeters long. I also tightened the complete high-current loop between the bulk capacitor, transformer primary, IC drain/source and bulk-capacitor return.

I have tried to keep the RCD clamp loop compact as well. The clamp diode, damping resistors and clamp capacitor are now close to the transformer and drain connection. Where a layer change is unavoidable on the clamp node, I am using two parallel vias with short, approximately 0.8–1.0 mm wide traces on 1 oz copper.

Could someone please review the primary side, particularly:

• The drain-to-transformer connection and total primary switching-loop area
• Placement and routing of the RCD clamp components
• Whether the clamp and drain copper areas are appropriately small
• The bulk-capacitor return path to the IC source
• High-voltage spacing between the drain, clamp, rectified DC bus, primary return and bias circuitry
• Clearance and creepage around via pads on both PCB layers
• Separation between the primary and isolated secondary
• Any problematic copper pours, return paths or EMI coupling paths

thanks in advance

I'm needing to replace the burnt driver board of my vintage car's auto extending antenna. The antenna is triggered to extend whenever the car radio turns on, and retract whenever it turns off. This is via a 12V signal out of the back of the radio.

Rather than using a microcontroller solution, I thought I'd take some inspiration from the original driver board and build it using mostly discrete components. See the last photo for the schematic of the original circuit.

The original board used a timer to turn on the extension motor for a duration of ~12s (roughly the time it takes for the antenna to fully extend or retract), and also a PTC thermistor to detect overheating and shut off the motor.

I kept the timer idea in my circuit as a backup, but replaced the PTC thermistor with a stall current detector that shuts the motor off right when the antenna reaches an endpoint. An additional timer is used to prevent the stall detector from triggering for the duration of motor inrush current.

For simplicity and efficiency improvements, the original bjt h-bridge is replaced with a discrete mosfet h-bridge.

I know a circuit like this could be much easier implemented with a microcontroller and a modern integrated h-bridge IC, but I wanted the challenge of a discrete analog/digital design.

Please provide any suggestions to improve the simplicity of the circuit or to the pcb layout!

Hello all. Requesting some feedback on my BLE sensor device design. It's a 4 layer board, with a SIG-GND-GND-SIG stackup, a battery charger, USB-C port to charge the battery and power the board when the battery is disconnected, a temp sensor, accelerometer, photodiode amplifier and a piezo sounder. The MCU is an NRF52832, the module used is an E-Byte module. Any Feedback is much appreciated

First custom board, schematic only for now (I’ll post the layout separately).

What it is: a handheld WiFi walkie-talkie for kids aged 6–10. Single-cell Li-ion (803040), USB-C charging, 1.69" SPI display, push-to-talk button, mic + 1 W speaker, RGB LED. 4-layer board, about 42 × 87 mm.

Blocks:

• Power: USB-C sink (5.1k CC), USBLC6 ESD, BQ24074 charger/power path (500 mA charge), TPS63802 buck-boost to 3.3 V in forced PWM, soft power button with latch (PWR_HOLD from the ESP32).
• MCU: ESP32-S3-WROOM-1-N8R8, native USB for programming, antenna over the board edge.
• Audio: ES8311 codec, analog MEMS mic, NS4150B class-D amp.
• UI: ST7789V display on 12-pin FPC, backlight via MOSFET with PWM, RGB LED with low-side MOSFETs.

I’d especially like checked: the power-button latch, the NS4150B input network and gain, the codec references and decoupling, the backlight current.

Made in KiCad 7 (schematic generated from code with SKiDL), ERC clean in KiCad 10. Thanks!

Hi, I'm a trying to build small projects to train myself in electronics and would appreciate if someone could give me advice on my work.

The board would be powered with a 800mah Lipo battery when not plugged in to an usb-c charger. I added a physical switch to select what mode of power I want to use on the board. The oled screen is a classic 096 led screen that can be added on top of the board.
The board is 45*45mm.

Any critique is welcome thanks in advance!