r/PrintedCircuitBoard

Hi everyone!

This is my first PCB, so I'm posting the schematic and PCB layout (4-layer) here to ask for a review. I'd really appreciate any feedback, especially if you spot mistakes or design choices that could be improved. I'm mainly interested in learning from the mistakes before I manufacture the board.

The PCB is a small battery-powered device for measuring force using a half-bridge strain gauge, while also acquiring motion data from an IMU.

Main components:

- ESP32-C6 = main MCU (Bluetooth communication)

- MCP3561 = ADC for acquiring the strain-gauge signal

- BMI270 = 6-DoF IMU for acceleration and gyroscope measurements

- TPS63020 = buck-boost converter generating 3.45V from a 1S LiPo battery

- LP5907 = LDO generating 3.3 V from the 3.45 V rail

- TPS3700 = battery undervoltage/discharge protection

The PCB has the following pogo-pin connections:

- 2 pins for battery charging

- 2 pins for measuring an external resistor value

- 4 pins for connecting the two strain gauges forming the half-bridge

Q1 and Q2 are intended to protect the battery from a short circuit if the pogo-pin contacts are accidentally shorted by a conductive/metallic surface.

Any criticism is welcome because this is my first PCB and I'm trying to learn as much as possible before sending it to manufacturing.

Thanks!

It's an mp3 player using a pcm5102a, TRRS headphone jack, microSD reader, USB C, ESP32-S3-N16R8, female headers, tp4056, and a battery connector (picoblade). I'm using a SPDT slide switch as a SPST slide switch (couldnt find any SPST ones, so I had to make do).

I'm routing VBAT through the switch and routing out vbat_clean out of it, but for the TP4056 module, i connect the BAT pin to VBAT and NOT vbat_clean, is this okay? (primary question)

Please let me know if there's anything wrong or if I should change anything because It's my first ever schematic and I pretty much have no idea what I'm doing haha.

This is supposed to be an e-reader using an esp32 wroom 32U, usb micro b, micro sd card connector, some sw-push buttons, fpc connector (KH-FG0_5-H2_0-24PIN), and LDO (TC1262-33).

I dont really want this to be battery powered at the moment, since its a prototype and I just dont want to deal with a battery.

I really just dont want this thing to explode, start a fire or fry the e-ink display and I want to be able to program the ESP32.

Unfortunately more e-reader slop to look over, but I would appreciate any insight as I don't really know what I am doing.

Thanks.

Hello,
this is probably my third PCB so I still don't know what I am doing. Sorry If the schematic above is unclean or badly wired.

This schematic includes:
Arduino uno - only 6 pins are needed
74HC595 shift register
8 LEDs.

I though I would make a PCB out of this because it will look way cleaner than what I have here on my breadboard. I have one question though, why do I need a capacitor between 74HC595 pins 16 and 8? I was recommended to put one by gemini...

Anyway, thanks for reading this!

Thanks for taking a moment to look here. This is a PCB for a screw compressor (which has a physical safety pressure relief valve!)

The screw compressor is actuated by a VFD communicated over using modbus, and controlled with the pressure sensor and the so-called unloading solenoid (allows compressed air back into the intake to help the motor start when under pressure).

I think the circuit consists mostly of 3 interesting parts, the 4..20mA pressure sensor, the solenoid actuator through a mosfet and the power circuitry where I am for the first time using this MPM3550 IC which seems like a very robust power IC.

I'm grateful for any feedback. Manufacturing of this incl. assembly with JLCPCB is $73 including shipping for 5 boards, 2 assembled. I'm on the fence whether to spare costs by going a different route with the 42v->5v regulator but I quite like this IC and I'd like to try it once.

Thanks in advance!

Hey,

I designed a circuit board using an ESP32, it is designed to be an audio player with Ethernet support. I am currently having issues with the W5500 Ethernet chip overheating, and I cant figure out why. I copied the datasheet for the design. I already addressed the 3.3v power issue (I had a 3.3v net and a +3V3 net that weren't connected).

Does anyone have any tips on how to improve this circuit?

Thanks!

Hello everyone!

I recently finished designing my first 4-layer PCB, and before I send it off for fabrication, I would really appreciate some experienced eyes on it.

The board is based around the AD5941 and is intended for an Electrochemical Impedance Spectroscopy (EIS) experiment. I designed it myself primarily because the commercially available development/evaluation boards are expensive and relatively large for our application.

This is my first time designing a 4-layer board, and while I have tried to follow the AD5941 datasheet and evaluation-board recommendations as closely as I could, I am sure there are things I have overlooked.

In particular, I would be interested in hearing from anyone who has worked with the AD5940/AD5941 IC.

I have attached the schematic and PCB layout. Please feel free to point out anything that looks wrong, even if it seems minor. I would much rather catch a mistake now than discover it after receiving a box of useless PCBs.

NOTE: The Back Copper layer is used to separate the AGND and DGND regions. They are kept separated on this layer and ultimately connect at the GND layer.

I don’t have any prior experience designing mixed-signal circuits, so I have tried to follow the AD5941 datasheet, schematic available on the Analog Devices website and other layout recommendations as closely as possible.
I would especially appreciate any feedback on whether my approach to the analog/digital grounding is appropriate.

Goodnight everybody!

So, I have been dabbling with PCBs and electronics for some time, got distracted with life and now I'm discovering the wonderful world of ESP32.

So, first off, what is this thing?

Its supposed to be a fan controller for my homelab, and with some luck it will expose some controls and data to my home-assistant instance , it features:

• ESP32-S3
• Wiznet W5500
• EMC-2505
• HDC-2080
• An Molex/ATX HDD power connector.
• Maybe a couple WS2812B RGB leds.
• All on a 4 layer PCB (no specific stackup): 1- Sig, 2-Gnd, 3- 3.3V, 4- Sig.

My main doubts are:

• Is my OR-ing with the diodes makes sense, and if I can power the WS2812B leds after the diode drop.
• Is the SPX3819M5-L-3-3 a viable LDO or is there something better/more jellybean, I'm trying to avoid the LM1117/derivatives due to the large Vdrop.
• Anyone has a 3D model for the ATX HDD (PATA) power connector? I managed to find this parts that should work, just no 3D model:
  • TE Connectivity 641737-1
  • XFCN M5082RK-B-04P
  • XKB Connection X5050WR-04S-N2SN
• I'm not really feeling the current layout, seems like a lot of wasted space currently, just doesn't feel quite like nice.
  • The PCB for now measures 90x65mm.

The USB connector is mainly for initial development/debug, it will then be powered by the ATX HDD power cable, if it helps.

Best regards, and thanks for your time!

Hi,

This is my first PCB, so I’m open to any criticism and would really appreciate any advice or feedback!

My goal here is to keep things simple and make a wired mouse using the STM32F411CEU6 (weact blackpill) and a pixart paw sensor.

I looked through the datasheets of both the mcu and the sensor and weact studio blackpill schematic as well as asked ai for explanations.

Some of the significant components:

Sensor - PAW3395DM-T6QU
MCU - STM32 F411CEU6
LDO (1V8) - XC6206-1.8
LDO (3V3) - AP2112K-3.3
Crystal (25MHz)- 7E25000E20UCG
USBC - HRO TYPE-C-31-M-14

Screenshots of the schematic and PCB should be attached (Not sure if I’ve followed the steps properly in screenshotting but i tried to make it clear as possible and copy the format of other’s screenshots)

I ran the drc which came back with errors on the sensor pins being too close to the edge, however the footprint came like that so I assume that part is fine?, however there were also warnings with the silkscreen on the usb (clipping board edges, clearance and solder mask) (downloaded the footprint from ultralibrarian, not sure if these errors are expected or if I should edit the foot print)

Thank you in advance for taking the time to give advice or feedback. I really appreciate it!

Hi All - full disclosure, I'm a software person who has used a fair bit of AI to go from "I think I understand ohms law" to an actual circuit board design; I think I've validated everything against datasheets and other sources, but I don't know what I don't know. A lot of the part choices are driven by what I have to hand or is cheap on Digikey, but please point out if any of those choices seem weird.

I'm trying to put together a simple Raspberry Pi HAT for my homelab with:

• A basic RTC (PCF85063AT) - doesn't need to be super precise, but enough that NTP can take over after boot. Deliberately using a CR2032 instead of a supercap for cost.
• A handful of status LEDs via an PCA6554 I2C IO expanded - I could drive these directly via GPIO, but I want to keep these free as much as possible
• A ATECC608B crypto chip to securely store auth keys/SSL certs/...
• External connectors for UART and a pair of GPIO lines
• An external connector for the I2C bus - planning on getting a small OLED display and connecting that up

Board will be mounted in a 3d-printed sled and mounted with the connectors and LEDs pointing out, using Wurth 155124xS73200 series LEDs for this.

Total volume is 5-10 units, I've done some SMD soldering but I'm planning on getting a stencil made and using an old toaster oven and ChipQuik Bi/Sn/Ag solder paste instead to make it a bit easier.

Thanks!

Hi, I've tried to make a copy of CJMCU-PAM8006 breakout board to test it and integrate it on my final board. Right now, I only need one channel for my mono speaker application. All of the Left channel side is unmounted and left channel power is not connected.

The board itself seems to work, but the sound coming out of the speaker is much weaker than on the board I bought.

On the original board, there is no PL (Power Limit) resistor, so it is on DMP on mine as well.

Can you spot any no no's on the schematics?

Hi everyone!

I am a backend developer by trade, but recently I've picked up amateur radio as a hobby. I am designing a piece of hardware to handle communication between a radio and a phone for an APRS app.

What you see in the screenshots is the result of 1.5 weeks of learning PCB design in the evenings. In parallel with designing in EDA software, I built two working prototypes on protoboards (included in the photos) to verify the circuit. Now I am trying to route the final PCB, but since this is my very first design, I desperately need a technical review before I send it to manufacturing.

Here are my core design assumptions:

• Brain: Ready-made ProMicro nRF52840 module.
• Components: Strictly THT to make it beginner-friendly and easy to DIY.
• Audio Input Filtering: Bandpass filtering tailored for AFSK (1200 Hz for Mark / 2200 Hz for Space) for signal decoding.
• Power Input Protection: Reverse polarity protection, alternator whine filtering (for mobile/car use), and transient voltage spike protection.
• Goal: To release this as an open-source / open-hardware project once the PCB layout is correct.

I am explicitly seeking a strict technical review to ensure I didn't mess up.

Specific questions for the reviewers:

1. Is my routing clean enough, or did I make amateur mistakes with trace widths, clearances, and angles?
2. Are there any obvious issues with component placement, signal separation, or ground planes?
3. Is the power filtering and protection layout robust enough for an automotive environment?
4. What could be improved to make it even easier for beginners to solder?

Attached are the schematic and layout layers. Thank you in advance for your time and constructive criticism!

Hi everyone,

This is my first PCB design, I'm using the LM2596S Buck converter IC with an estimated current output of 1.5-2A and voltage input of 11.6V nominal through a 3 lipo battery pack. I have also paired this with the TBB12FNG Motor driver IC on the same PCB. I will this connect this PCB up with an esp32 via the male header pins to power a RC car I'm building. This is a two layer board with a upper copper plane and a bottom ground plane. I have picked the components, their values and layout through reading respective datasheets. I would appreciate some feedback on this design and what I can improve/change. I'm quite unsure about the routing connections and would appreciate feedback on that too.

Thanks

Hi everyone,

Two friends of mine wanted to do their final high-school research project (PWS for the Dutch folks) on piezoelectric energy harvesting and the possibility of using the generated energy for real-world applications. I told them numerous times that the amount of energy generated by piezo elements is exceptionally low, but they still wanted to research the piezo effect

Their main goal is to investigate how much energy piezo elements can generate and compare different elements to see how properties such as diameter, excitation frequency, impedance, and capacitance influence the harvested energy. To give them a way to measure this, I decided to design a PCB for them.

The main measurement method uses a programmable capacitor bank. By measuring the voltage increase, they can calculate the stored energy. Making the capacitance programmable also allows them to analyse which capacitance is optimal for charge transfer and storage. By using both MLCCs and electrolytic capacitors, they can also analyse differences in leakage current.

Since they also wanted to learn how to use an oscilloscope, I added a parallel load resistor to the capacitor bank. This can be used to measure energy delivered to a resistive load, as well as to discharge the capacitor bank. With no capacitors connected, the same setup can also be used to measure the losses of the full-bridge rectifier.

The ADC has a VREF​ of 2.048 V, so a resistor divider scales the maximum 10 V input down to 2.032 V. We don't intend to charge the capacitors beyond 8 V. A MOSFET disconnects the ADC and resistor divider when they're not being measured to prevent continuously draining the capacitor bank.

The goal was to provide as many research possibilities as possible while keeping the cost relatively low. I know there are dedicated piezo energy-harvesting ICs, but they are relatively expensive and would give the students less opportunity to experiment with the individual components.

The PCB is 40mm in diameter to fit in a custom designed case with a load cell to be able to apply a constant bending force to the piezo elements. The case will also support the extending connectors.

Are there any problems or potential improvements you can see with this PCB or measurement approach?

All feedback is greatly appreciated!

P.S. Any recommendations for a budget-friendly buffer op-amp would also be appreciated.

Hey,

I'm currently working on a switching regulator board based on the TPS54202. I basically took the reference circuit from the datasheet and tried to stick as closely as possible to the suggested layout example. The concept is that power enters through the 3-pin connector at the bottom (in my case likely mostly 12V) and gets regulated down to 3.3V and outputted through the same connector.

I don't have any prior experience dealing with EMI. Does this board look like it should work as is? Is the SW copper pour too small? Are the vias on the SW pin of the IC sufficient? And is the connection between the SW pin and the copper pour with the vias big enough?

Thanks in advance for any feedback!

Hi all, hope you're doing well. I'm a student, awefully inexperienced, and I'd really appreciate a professional set of eyes on this. I plan to post two more updates after taking in advice and be done with this within next 2 days.

The board takes RS485, a 0-10V input and a 4-20mA input from outside. It outputs a +24V-or-open discrete signal, a 0-24V output at up to 1A, and a switchable resistance across two terminals. The 1A is transient only, not continuous. STM32G474, 4-layer planned. Schematic only, no layout yet.

I've assumed you won't have time to open datasheets, so take it as given that per-component current and voltage ratings have been checked. My real questions are more fundamental:

1. Will this circuit work at all? That's honestly my main worry.
2. Are any of these blocks more complicated than they need to be? If something here has a standard, simpler solution I don't know about, I'd love to hear it. This is extremely important, i am out of ideas. Anything that doesn't break isolation and simplifies my desing would make my day.
3. Is anything redundant, or doing a job something else already does?

I used an external SPI ADC instead of the MCU's own ADC, because the MCU sits on the isolated ground and I don't think an ADC pin can read a divider referenced to the other ground without shorting the isolation. And for the 0-24V output I ended up with an op-amp driving a BJT inside the feedback loop, because I couldn't find another way to get a controlled 0-24V while supplying 1A peaks. If there's a better standard approach to either, please tell me. I plan to do both debugging and uploading using STM by using boot and reset bottons.

I also have very no idea how to approach the PCB layout for this, especially the two ground regions, so any pointers there would help a lot.

Sorry if anything is unclear. This is my second or third PCB and by far the most complex thing I've attempted.

I have a Controleo 3 DIY reflow oven. I tried to reflow this custom board but some components seem to be a bit off. The board works fine, so I guess this is good enough, but if you have some tips to improve the result and avoid potential failures, please tell!

I am using a low temp solder paste Sn42/Bi57/Ag1. This paste is a couple years old (I don't use it enough to always use fresh solder paste), it was stored in the fridge when not in use. The reflow profiles peaks at ~185°C for around 45s. The board has an ENIG finish, and is 1mm thick.

Thank you!

Battery-powered smart coaster using an ESP32-C3, HX711 load-cell ADC, MFRC522 RFID reader, USB-C, TP4056 charger, and Li-ion battery protection. I’d appreciate your feedback on the design, especially any errors, missing components, or areas that should be improved before moving forward with the PCB design.

First time KiCad user here, with little knowledge in electronic !

I'm starting from an existing design, a PCB that digitizes 4 audio channels simultaneously, imported from Eagle (original format) into KiCad.

Here's the original design in KiCad, ADC 1.0:

SCH ADC 1.0 (first picture) / PCB ADC 1.0 (second picture)

The first problem is that the 6-pin oscillator reference (U1, top right) used by the original circuit (DSC1101BI5-024.5760) no longer exists — it's out of stock everywhere.

So I replaced it with a much more widely available 4-pin model (SX3M24.576B10F20TNN). It seems compatible to me, and my wiring seems sound, but I'd like to get confirmation on that:

PCB ADC 1.1 (third picture)

Next, the goal would be to be able to plug 4 electret microphone capsules directly into this circuit. For electret capsules (which need power, but generally only have 2 pins total), you need a power supply (MICBIAS) plus additional capacitors and resistors to make it functional.

I got this wiring diagram to help me understand what was needed (fourth picture), with 4.4µF capacitors and 2.2KΩ resistors.

Does that seem right to you?

Based on that, I made ADC 1.2, replacing the entire bottom section:

PCB ADC 1.2 (fifth picture)

What do you think of the final logic and KiCad file? Does it seem viable to you?

Thanks!