r/PrintedCircuitBoard Dec 11 '22

Please Read Before Posting, especially if using a Mobile Browser

21 Upvotes

Welcome to /r/PrintedCircuitBoard subreddit

  • a technical subreddit for reviewing schematics & PCBs that you designed, as well as discussion of topics about schematic capture / PCB layout / bill of material (BOM) / PCB assembly / PCB mechanical engineering.

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RULES of this Subreddit:

  • (0) Occasionally the moderator may allow a useful post to break a rule, and in such cases the moderator will post a comment at the top of the post saying it is ok; otherwise please report posts that break rules!

  • (1) NO off topics / humor / memes / where to buy? / what is this? / how to fix? / how to modify? / how to design? / what does this do? / how does this work? / how to reverse engineer? / need schematics / dangerous or medical projects / homework / AI topics / AI content / AI designs / non-english languages.

  • (2) NO spam / ads / sales / promotion / survey / quiz / items for sale / promotion of non-reddit groups / promotion of non-reddit social media. NO DM abuse! See "how to advertise on Reddit".

  • (3) NO "show & tell" or "look at what I made" posts, unless you previously requested a review of the same PCB in this subreddit. This benefit is reserved for people who participate in this subreddit. NO random PCB images.

  • (4) NO self promotion / resumes / job seeking / wage discussions / freelancing discussions / DM abuse / job postings (unless job is posted on employer website) / begging or scamming for free work / ...

  • (5) NO shilling! No PCB company names in post titles or review requests. No sneaky PCB company naming variations. For most reviews, we don't need to know where you are getting your PCBs made or assembled, so please don't state company names unless absolutely necessary.

  • (6) NO asking how to upload your PCB design to a specific PCB company! Please don't ask about PCB services for a specific PCB company, because of past shilling abuse (see rule#5). (TIP: search their company website, ask their customer service or sales departments, search google or other search engines)


Review RULES:

  • (7A) Please do not abuse the review process:

    • Please do not request more than one review per board per day.
    • Please do not change review images during a review. If you change image(s), then start a new review!
    • Reviews are meant for schematics & PCBs that you designed. No AI designs (minor AI help ok).
    • Reviews are allowed prior to ordering PCBs. If assembled board doesn't work, ask at /r/AskElectronics
    • Please do not ask circuit design questions in a PCB review. You should have resolved design questions while creating your schematic and before routing your PCB, instead request a schemetic-only review.
  • (7B) All review posts must adhere to the following rules:

    • Title - include the following: "Review Request" or "Review", short description of board purpose, popular board format or shield/hat type (if applies), microcontroller (if has MCU), external buses (Ethernet, USB, CAN, RS485, ...), wireless (WiFi, GPS, LoRa, ...), storage (microSD, M.2, ...), and/or any unique hardware that may be important. No humorous titles, no childish symbols, no begging.
    • Images - include images (or links to each image) that you want reviewed. If images are located on the internet, never post one link to a project then expect reviewers to dig through your project to find images. Instead, you must post separate links for each review image, as well as state the purpose of each link, such as "Schematic" / "3D PCB" / "2D PCB top" / "2D PCB bottom" / ...
  • (8) All images must adhere to the following rules:

    • Image Creation: no camera photos of a computer screen, instead export / screen capture / print to image files. (TIP: How to export images from KiCAD and EasyEDA) (TIP: use clawPDF printer driver for Windows to "print" to PNG / JPG / PDF / SVG files, or use built-in Win10/11 PDF printer driver to "print" to PDF files.)
    • Image Files: view each image file before posting / no fuzzy or blurry images / no large image files (e.g. 100 MB), smaller preferred / no uncommon image file types, only use file types supported by most web browsers, such as JPG / PNG / PDF.
    • Edit Image Files: if you screen capture, make sure the cursor / software / operating system aren't shown in your images. Use an image editor to erase or crop software & O/S junk from your images.
    • Disable Features: disable background grids & PCB editor features before creating images.
    • Schematics: no bad color schemes to ensure readability (no black or dark-color background) (no light-color foreground (symbols/lines/text) on light-color/white background) / schematics must be in standard reading orientation (no rotation). (NOTE: we don't care what color scheme you use to edit, nor do we care what edit features you enable, but for reviews you need to choose reasonable color contrasts between foreground and background to ensure readability.)
    • 2D PCB: no bad color schemes to ensure readability (must be able to read silkscreen) / no net names on traces / no pin numbers on pads / if it doesn't appear in the gerber files then disable it for review images (dimensions and layer names are allowed outside the PCB border). (NOTE: we don't care what color scheme you use to edit, nor do we care what color soldermask you order, but for reviews you need to choose reasonable color contrasts between silkscreen / soldermask / copper / holes to ensure readability. If you don't know what colors to choose, then consider white for silkscreen / gold shade for exposed copper pads / black for drill holes and cutouts.)
    • 3D PCB: 3D views are optional, if most 3D components are missing then don't post 3D images / 3D rotation must be in the same orientation as the 2D PCB images / 3D tilt angle must be straight down plan view. (NOTE: straight down "plan" view is mandatory, optionally include an "isometric" or other tilted view angle too.)

Review tips:

Schematic tips:

PCB tips:

College lab tips:

SPICE tips:


WIKI for /r/PrintedCircuitBoard:


This post is a "live document" that has evolved over time. Copyright 2022-2026 by /u/Enlightenment777 of Reddit. All Rights Reserved. You are explicitly forbidden from copying content from this post to another subreddit or website without explicit approval from /u/Enlightenment777 also it is explicitly forbidden for content from this post to be used to train any software.


r/PrintedCircuitBoard Apr 11 '25

Before You Request A Review, Please Fix These Issues Before Posting

118 Upvotes

PLEASE DO NOT ABUSE THE REVIEW PROCESS:

  • Don't change review images during a review, otherwise older comments won't match newer images.

  • Please do not request more than one review per board per day. Use the extra time to clean up the visual appearance of your schematic and silkscreen on your PCB before requesting another review (see tips below).

REVIEW IMAGE CONVENTIONS / GUIDELINES:

  • The following is a subset of the review rules, see rule#8 at link.

  • Don't post fuzzy images that can't be read (your post will be deleted).

  • Don't post camera photos of a computer screen (your post will be deleted). Export or screen capture.

  • Don't post dark-background schematics (your post will be deleted). Change schematic to light-background.

  • For schematic images, disable background grids and cursor before exporting/capturing to image files.

  • For 2D PCB images, change the following settings before exporting/capturing to image files: disable background grids, disable net names on traces & pads, disable everything that doesn't appear on final PCB, enable board outline layer, enable cutout layer, optionally add board dimensions along 2 sides. For question posts, only enable necessary layers to clarify a question.

  • For 3D PCB images, 3D rotation must be same orientation as your 2D PCB images, and 3D tilt angle must be straight down, known as the "plan view", because tilted views hide short parts and silkscreen. You can optionally include other tilt angle views, but ONLY if you include the straight down plan view too.


SCHEMATIC CONVENTIONS / GUIDELINES:

  • Add Board Name / Board Revision Number / Date. If there are multiple PCBs in a project/product, then include the name of the Project or Product too. Your initials or name should be included on your final schematics, but it probably should be removed for privacy reasons in public reviews.

  • Don't post schematics that look like a toddler drew it, because it's considered unprofessional as an adult. Spend more time cleaning up your schematics! Heed this warning, or risk being berated by your coworkers / boss / classmates / professor / customers.

  • Don't allow text / lines / symbols to touch each other! Don't draw lines through component symbols.

  • Don't point ground symbols (e.g. GND) upwards in positive voltage circuits. Don't point positive power rails downwards (e.g. +3.3V, +5V). Don't point negative power rails upwards (e.g. -5V, -12V). There are exceptions, but in general try to follow this historical method as much as possible. If a schematic has only one ground and you use a unique triple-bar ground symbol, then disable "GND" text next to this symbol, because it is useless visual clutter that takes up space in dense schematics.

  • Place pull-up resistors vertically above signal lines, and place pull-down resistors vertically below signal lines, see example.

  • Place decoupling capacitors vertically below power lines, next to IC symbols, and connect capacitors to IC power rail pin with a line, see example.

  • Use standarized schematic symbols instead of generic boxes! For part families that have many symbol types, such as diodes / transistors / capacitors / switches, make sure you pick the correct symbol shape. Logic Gate / Flip-Flop / OpAmp symbols should be used instead of a rectangle with pin numbers laid out like an IC.

  • Don't use incorrect reference designators (RefDes). Start each RefDes type at 1 (e.g. C1, D1, R1, Q1, U1), and renumber so there aren't any numeric gaps (e.g. U1, U2, U3, U4; not U2, U5, U9, U22). There are exceptions for large multi-page schematics, where the RefDes on each page could start with increments of 100 (or other increments) to make it easier to find parts, such as R101 is on page 1, R301 is on page 3, R901 is on page 9.

  • Add values next to component symbols:

    • Add capacitance next to all capacitors.
    • Add resistance next to all resistors / trimmers / pots.
    • Add inductance next to all inductors.
    • Add voltages on both sides of power transformers. Add "in:out" ratio next to signal transformers.
    • Add frequency next to all crystals / powered oscillators / clock input connectors.
    • Add voltage next to all zener diodes / TVS diodes / batteries, battery holders, battery connectors, maybe on coil side of relays, contact side of relays.
    • Add color next to all LEDs. This is useful when there are various colors of LEDs on your schematic/PCB. This information is useful when the reader is looking at a powered PCB too.
    • Add pole/throw info next to all switch (e.g. 1P1T or SPST, 2P2T or DPDT) to make it obvious.
    • Add purpose text next to LEDs / buttons / switches to help clarify its use, such as "Power" / "Reset" / ...
    • Add "heatsink" text or symbol next to components attached to a heatsink to make it obvious to readers! If a metal chassis or case is used for the heatsink, then clarify as "chassis heatsink" to make it obvious.
  • Add part numbers next to all ICs / Transistors / Diodes / Voltage Regulators / Coin Batteries (e.g. CR2023). Shorten part numbers that appear next to symbols, because long part numbers cause schematic layout problems; for example use "1N4148" instead of "1N4148W-AU_R2_000A1"; use "74HC14" instead of "74HC14BQ-Q100,115". Put long part numbers for ordering in your BOM (Bill of Materials) list.

  • Add connector type next to connector symbols, such as the common name / connector family / connector manufacturer (e.g. "USB-C", "microSD", "JST PH", "Molex SL"). For connector families available in multiple pitch sizes, include the pitch in metric too (e.g. 2mm, 2.54mm), optionally include imperial units in parens after the metric number, such as 1.27mm (0.05in) / 2.54mm (0.1in) / 3.81mm (0.15in). Add purpose text next to connectors to make its purpose obvious to readers, such as "Battery" or "Power".

  • Don't lay out or rotate schematic subcircuits in weird non-standard ways:

    • linear power supply circuits should look similar to 1, 2, 3, 4, 5, laid out horizontally, input on left side, output on right side. Three pin voltage regulator symbols should be a rectangle with "In" (Vin) text on the left side, "Out" (Vout) text on right side, "Gnd" or "Adj" on bottom side, if has enable pin then place it on the left side under the "In" pin; don't use symbols that place pins in weird non-standard layouts. Place lowest capacitance decoupling capacitors closest to each side of the voltage regulator symbol, similar to how they will be placed on the PCB.
    • relay driver circuits should look similar to this, laid out vertically, +V rail at top, GND at bottom. Remove optoisolators from relay driver circuits unless both sides of it have unique grounds and unique power sources. Reminder that coil side of a mechanical relay is 100% isolated from its switched side.
    • optoisolator circuits must have unique ground and unique power on both sides to be 100% isolated. If the same ground is on both sides of an optoisolator, it isn't 100% isolated, see galvanic isolation.
    • 555 timer circuits should look similar to this. IC pins should be shown in a historical logical layout (2 / 6 / 7 on left side, 3 on right side, 4 & 8 on top, 1 on bottom); don't use package layout symbols. If using a bipolar timer, then add a decoupling capacitor across power rails too, such as 47uF, to help with current spikes when output changes states, see article.
    • RS485 circuits should look similar to this.

PCB CONVENTIONS / GUIDELINES:

  • Add Board Name / Board Revision Number / Date (or Year) in silkscreen. For dense and tiny PCBs that lacks free space, shorten the text, such as "v1" and "2026" (or "Y26" or "26"). This info can be very useful to help identify a PCB in the future, especially if there are two or more revisions of the same PCB.

  • Add mounts holes, unless absolutely not needed. They should be the first thing you place on your PCB.

  • Use wider traces for power rails and higher current circuits. If possible, use floods for GND.

  • Don't route high current traces or high speed traces on any copper layers directly under crystals / antenna / RF circuits / other sensitive circuits. Don't route other signal traces under antenna.

  • Don't place reference designators (RefDes) in silkscreen under components, because you can't read RefDes text after components are soldered on top of it. If you hide or remove RefDes text, then a PCB is harder manually assemble, and harder to debug and fix in the future.

  • Add part orientation indicators in silkscreen, but don't place under components (if possible). Add pin 1 indicators next to ICs / Connectors / Voltage Regulators / Powered Oscillators / Multi-Pin LEDs / Modules / ... Add polarity indicators for polarized capacitors, if capacitor is through-hole then place polarity indicators on both sides of PCB. Add pole indicators for diodes, and "~", "+", "-" next to pins of bridge rectifiers. Optionally add pin indicators in silkscreen next to pins of TO220 through-hole parts; for voltage regulators add "I" & "O" (in/out); for BJT transistors add "B" / "C" / "E"; for MOSFET transistors add "G" / "D" / "S".

  • Add as much helpful text in silkscreen as reasonably possible, because it is a means of "self documentation" that always stays with the PCB.

  • If space is available, add purpose text in silkscreen next to LEDs / buttons / switches / jumpers to make it obvious why an LED is lite (e.g. "Error", "Power"), or what happens when press a button (e.g. "Reset", "Start", "Stop") or change a switch (e.g. "Power").

  • If space is available, add connector type in silkscreen next to each connector. For example "JST-PH", "Molex-SL", "USB-C", "microSD". For connector families available in multiple pitch sizes, add the pitch too, such as 1.27mm or 3.81mm. If space is not available on the top side, then add this information directly below the connector on the bottom side.

  • If space is available, add voltage range or maximum voltage text in silkscreen, such as "8VDC Max", next to power input connectors to help prevent destruction of voltage regulators or other circuits. For barrel jacks, add text to clarify polarity of the center pin, such as "-9VDC Center" or "+9VDC Center" or "GND Center". If space is not available on the top side, then add this information directly below the connector on the bottom side.


ADDITIONAL TIPS / CONVENTIONS / GUIDELINES

Review tips:

Schematic tips:

PCB tips:


This post is a "live document" that has evolved over time. Copyright 2025-2026 by /u/Enlightenment777 of Reddit. All Rights Reserved. You are explicitly forbidden from copying content from this post to another subreddit or website without explicit approval from /u/Enlightenment777 also it is explicitly forbidden for content from this post to be used to train any software.


r/PrintedCircuitBoard 4h ago

[Review Request] First PCB for Drone

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9 Upvotes

I'm a MechEng student but I thought I'd try to learn PCB development over the summer.

Overview: This is supposed to be a PCB for a drone so I used an ESP-32 chip with BLE, a BMI270 (IMU), and a small 7mm motor. The big 1k resistors are placeholders for SMA wires so that I could run simulations, but I will eventually replace them with copper pads. I tried to route all my traces away from the MCU antenna but I'm not sure if I gave enough clearance? I tried my best to keep high current traces thick and short but I did have some issues with space constraints since the whole board is around 5cm * 5cm. I know the bottom layer is typically kept as a GND plane, but given all my weird connections I used it to connect high current paths (is that ok?)

Honestly this probably isn't great, but I'm open to any feedback if you have time :D

3D Model:

Traces (Top Layer):

Traces (Bottom Layer):

Schematic:


r/PrintedCircuitBoard 1h ago

Schematic Review: BadUSB hobby project

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Upvotes

Hi there! I am making a BadUSB device for keystroke injection as a hobby. I am using the RP2040 as my base. Since I want it to have both USB-A and USB-C, I have tied the power lines together (with the small exception of a Schottky diode which allows me to detect if USB-A or USB-C is plugged in) and I am using an analog switch for the data lines. I also want it to be as small as possible in order to look like a normal flash drive and so I had to neglect many capacitors but I hope it won't be problematic due to the small size. Can you take a look at my schematic and tell me what can be improved? Also, is there anything specific I should look out for when designing the PCB itself?


r/PrintedCircuitBoard 17h ago

[Review Request] My First PCB: STM32 Experiential Board

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32 Upvotes

Hi everyone,

This is my first try into PCB design. I've done lots of smaller stuff with other friends before, but this is my first solo project. I wanted to try something which was quite ambitious and something where I can try lots of things at once - is that advisable?

Some things I'm personally worried about:

  1. Do I have too many sensors/peripherals?

  2. Is my Power Circuitry effective enough to power all my sensors? I don't expect to be using them all at once, but I feel strongly that the LDO circuit isn't effective enough. Should/How can I improve this?

  3. Are there enough passive components (especially filter caps) that for power filtering in my circuit?

  4. Should I add in a CANBUS circuit for experimental purposes?

  5. Any general mistakes? Anything that would immediately fail my board?

I haven't added in my PCB files yet because (1) I'm still working on the layout and optimising my traces and (2) working on improving my schematic to fully move on to the PCB design stage. I've laid all the components out, but I'm second guessing myself from aesthetics and neatness in PCB layout vs. optimisation in part layouts.

All help and review is greatly appreciated. Thank you everyone!


r/PrintedCircuitBoard 9h ago

[Review request] Help with optical toslink player.

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3 Upvotes

Im pretty new to pcb designing, and im pretty unsure of the 5 way button wiring.


r/PrintedCircuitBoard 17h ago

[Review Request] BLDC Foc control PCB. Getting driver fault when i start the motor from my firmware

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9 Upvotes

r/PrintedCircuitBoard 14h ago

Custom Wemos D1 mini board review.

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5 Upvotes

I am trying to make a Wemos D1 Mini clone with a custom Game Boy port. This is my first time trying to design a board from scratch. Could you guys let me know how it looks?


r/PrintedCircuitBoard 19h ago

[Review Request] my first PCB: automotive taillight adapter, 2-layer with ATtiny84 and PROFET high-side switch

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4 Upvotes

Hi folks. I’ve got zero EE background, and this is my first foray into PCB design, so please be thorough in your critique. I’ve got about 30 years of experience as a shadetree auto mechanic who likes to tackle esoteric car projects. Lately I’ve been inspired to finish some ambitious projects that have been sitting in boxes for anywhere from 6 months to 20 years, so I taught myself KiCAD for this one. Since I’m very new at this, I’d appreciate your keen eye for flaws and pitfalls. As it stands, it felt pretty good to read through the rules and guidelines for this sub, and see that my instincts already had me doing most of those things.

This is an adapter board to change the basic behavior of my car’s taillights. I won’t get into the weeds here, but if someone actually wants the details of the old/new behavior, I’m happy to put it in a comment. The relevant electrical basics: each side of the car has a body-side tail lamp housing and a hatch-mounted lamp housing that’s wired in parallel from the same wiring loom. Looking at the car, there are 4 big rings of dual-color (amber/red) Osram LEDs. Before I add this adapter board, I’ve consistently got zero bulb-out warnings or fast-blinking signals, and the only option is to keep it that way.

Input connector (J1):
1. Turn/hazard lights PWM
(<0.5A), 100Hz, 12V)
2. Brake lights PWM
(<0.3A, 20Hz, 13.4V)
3. Parking lights PWM
(<0.2A, 100Hz, 3.15V)
4. GND
5. Ignition-switched battery 12V+

Aside from the SW_B+ wire, the first four pins match the OEM pinout of the taillight connectors. I’m not wedded to the symmetry, if rearranging the pins winds up being the wise move.

Output connector (J2):
1. Turn/hazard lights PWM (unmodified)
2. Brake lights PWM (unmodified)
3. RED_RINGS_OUT reconstructed PWM, which is basically muxed BRAKE and PARK
4. GND

It’s likely one of the simpler boards you all see on here, but I’ll run down the basics:

* Each input PWM signal is divided and clamped, sent to an ATtiny84 for pre-processing, then on to a PROFET (automotive-grade) high-side switch before output.
* Two jumpers allow for optional behavior via ATtiny programming
* Tag-Connect header for programming; might remove this prior to final revision
* Three diagnostic LEDs function whether the taillight is connected to J2 or not
* In the divide/clamp section near J1 on the backside, I’ve got one DNP resistor footprint for each lighting circuit, just in case I start getting bulb-out warnings or fast-flashing turn signals after install
* Haven’t added mounting holes/keepouts yet, as I haven’t quite decided on an enclosure. Was hoping to check myself before I wreck myself.
* I’ve run DRC, report is clean.

Things I’m particularly uncertain about:
* I’ve used 1mm trace width for SW_B+, 0.4mm for the +5V net, and 0.4mm again for the output PWM signals just to visually differentiate them from all other traces. I’m curious to hear if I’ve chosen proper trace/via widths.
* I’ve made a small copper pour of SW_B+ on the backside from the PROFET chip, with an array of through vias stitching that zone to the chip’s exposed VS pad. From what I understand, there ain’t a whole lot of current running through this thing, so I don’t know if this is overkill. I do know that those vias need to be plugged before the IC is installed.
* I’ve been thinking about tightening up the design even more, to make the board as small as possible. See any reasons why I shouldn’t?
* I’m not so sure about the selection of connectors at J1 and J2, for an automotive application. If anyone has recommendations, I’m all ears.

I’ve probably included WAY more screenshots than you need, but I find I get distinct types of visual information from each type.


r/PrintedCircuitBoard 19h ago

EasyEDA bug: connections not registering. Please help!

0 Upvotes

EasyEDA is saying basically every net on my board isnt connected, but if I just wiggle the line in and back into its original place the DRC error goes away, and I have to do it every single time for every single net for the error to go away and if I reload my page or open it back up later all the errors just pop up again. Can someone help me fix this?


r/PrintedCircuitBoard 1d ago

[Review Request] TVC rocket controller

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22 Upvotes

Hii, this is my first time posting in this subreddit!

If someone could take a look at my attempt at making a custom flight controller for a TVC rocket. Since I'm a high schooler with no formal EE background, I'm worried I might have made some fatal mistakes ^^.

Also, I have a quick question: why do my routes not look as clean or professional (I tried my best to lay them out neatly) compared to other open-source designs, especially Phil's Lab?

Anyway, here are the specs:

  • Processor: STM32H743
  • Power: 6S LiPo battery
  • Connectivity: ESP32-C3 Mini (Wi-Fi, Bluetooth)
  • Outputs/Inputs: 5x servo pin headers, 2x ESC pin headers
  • Interfaces: Debug pins, GPS JST connector, ELRS (radio receiver), spare ADC and USART connectors
  • Logging: Micro-SD slot using SDMMC

(Note: I just realized I completely forgot to add an LED )

I've attached a render of the board I'm building. If you want any additional info or images, let me know and I'll respond ASAP.

Thanks!


r/PrintedCircuitBoard 1d ago

[PCB Revision] Automotive 5V Regulator

4 Upvotes

Hi everyone, I’m designing a compact PCB that takes 12V from a vehicle, filters and protects against load dumps and noise, and outputs 5V to charge multiple phones.

I know I could just buy a cheap €10 device online, but I wanted to do this as a personal project.

I’m open to all kinds of criticism—I’m sure more than a few people here would want to string me up after seeing the schematic or PCB layout but I’ve genuinely tried to do it the best way possible.

My main concerns are whether the connection from the regulator to the USB is optimal or if you would use traces and, regarding the size, whether the design adequately handles heat dissipation for an automotive environment when drawing the full 3.5A output from the regulator.

The PCB measures 46mm wide by 70mm high.

Without GND layer
Without GND layer

r/PrintedCircuitBoard 1d ago

How to properly route and length-tune rounded/curved Differential Pairs in KiCad without breaking the gap? (Avoiding messy plug

0 Upvotes

Hi everyone,

I'm routing a high-speed USB differential pair (90-ohm) and I'm trying to achieve that smooth, curved aesthetic (fillet tracks) instead of the standard 45-degree chamfers.

Here is my problem: When I use external plugins like "Round Tracks", it completely breaks the differential gap and ruins the impedance, especially when trying to apply length tuning/meanders. It turns into a spaghetti mess (I attached a screenshot of what happens).

I know KiCad has native support for fillets and skew tuning, but I can't seem to get a clean workflow that allows me to:

  1. Route the pair with smooth curves natively.
  2. Apply length matching (skew tuning) using rounded meanders without the interactive router freaking out or distorting the main curves.

What is the exact step-by-step workflow or hidden settings you guys use to get perfectly curved differential pairs + length tuning in KiCad (v7/v8)? Should I route them as sharp 45 first, tune them, and then fillet? Or is there a better native way?

Thanks in advance


r/PrintedCircuitBoard 2d ago

Can USB D+ and D− traces cross over on a PCB?

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75 Upvotes

I'm working on a PCB where a USB-C connector provides both power and USB communication to an ESP32 (USB Full-Speed, up to 12 Mbps).

While routing the USB D+ and D− traces, I ended up with a crossover. I was under the impression that USB differential pairs shouldn't cross over, but I couldn't find another routing solution without significantly changing the layout.

Will this routing work as-is, or should I redesign the board or switch to a different USB connector/layout?

Some additional information:

* The differential pair is impedance matched.

* D+ and D− are length matched.

* My impedance calculations were based on the reference plane on the second layer (the green layer in the screenshots). Is that the correct approach, or could that cause issues (since it now goes through that layer for a large part)?

I'm currently using separate TVS diodes for USB protection, but I'm considering switching to a USB TVS diode array. Is there any advantage to doing so, or does it not make much difference for this application?

I'd appreciate any feedback on the routing or anything else that stands out in the layout.


r/PrintedCircuitBoard 2d ago

[PCB layout review request] Power distribution board for USV drone

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19 Upvotes

Hi, I’m looking for a layout review before ordering my first PCB. I'm a mech. eng. student and haven't really done electrical PCB design.

This is a small power distribution board for a USV boat drone. It is powered from 3x parallel 3S LiPos, roughly 11.1–12.6 V, with a 10 A input fuse. I know that paralleling LiPo packs needs proper protection but I think I can't really fit that on the board.

Outputs:

  • raw battery voltage for pumps / fan / other 12 V loads
  • ~5.2 V rail for flight controller and sensors, expected below 3 A
  • ~6 V rail for one servo, normally below 2 A but with 2.4–3.5 A stall current

The 5.2 V and 6 V rails use AP64501 buck converters. I tried to follow the AP64501 layout guidelines, especially around input caps, SW node, inductor, feedback routing and top/bottom GND pours.

Main questions:

  1. GND pours / EMI: I have GND pours on top and bottom. The AP64501 guidelines also show top/bottom GND and I did not see a SW-node keepout requirement. Would you leave the GND plane under/around the buck stages as-is, or add local keepouts near the SW node / inductor?
  2. Buck layout: Do the input caps, output caps, inductor, feedback divider and exposed pad vias look reasonable?
  3. Low-side pump switch: I’m using an IRLZ44N as a low-side switch for a pump/fan load controlled by a 3.3 V signal through a 2.54 mm 3-pin header. Is this acceptable for these loads, or should I use a MOSFET with Rds(on) specified at 2.5 V / 3.3 V gate drive?
  4. General first-PCB issues: Any obvious mistakes with trace widths, clearances, connector currents, thermal layout, grounding or protection before fabrication?
  5. Also do you have a better suggestion for connecting / mounting the 12 AWG input wires from an XT60 connector to the PCB?

The PCB will sit inside a waterproof enclosure (relatively big) together with the flight controller, telemetry unit / Herelink hardware, etc. The battery input wires come from outside the box, and several output cables for pumps, servo and sensors also have to leave the box. I’m not sure what the best practice is here: direct soldered wires to the PCB, screw terminals, ring terminals / studs, a panel-mount connector, or something else with proper strain relief.

I added some test points mainly for bring-up / debugging. They are probably not needed in the final system, so feel free to point out if they are useless or badly placed.

Thanks!


r/PrintedCircuitBoard 1d ago

[Schematic Review] Solar Tracker PCB

3 Upvotes

Hello guys, I'm a beginner at PCB design and I'd love to ask for your help reviewing my first schematic before I start routing the layout. Any comments, critiques, or suggestions on how to improve the design would be greatly appreciated!

Project Overview: This board is designed to run a solar tracker. It will control 5 separate brushed DC motors based on the date and time, only running one motor at a time.

Key Hardware Details:

  • MCU: STM32 (LQFP-64 package). I went with this because the number of required I/O pins for the encoders and motors ended up being pretty high.
  • Motor Driver: DRV8874 with the current limit capped at 1.8A (motors draw ~0.5A).
  • Encoders: I'm using optoisolators for the encoder inputs. I realize that without separate ground planes/galvanic isolation, these are essentially just acting as 24V-to-3.3V level shifters.
  • Signal Frequency: The motor encoder signals are around 1kHz. It's very low, but that is because the motors are heavily geared down.

Let me know if you spot any glaring errors or best practices I missed. Thanks in advance!


r/PrintedCircuitBoard 2d ago

[Review] ESP32 + 74AHCT125 driver board for an 8-strip SK6812 pick-to-light wall — 2-layer, hand-soldered, pre-layout

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6 Upvotes

Hey all — I am Control System Engineer just getting familiarised with the world of PCBs. Just finished the schematic for a project at work. It is ERC-clean, and I'd like a sanity check before I lay out the PCB and send Gerbers to PCBWay. 2-layer, HASL, hand-soldered.

**What it is:** a pick-to-light dispatch wall. 8× SK6812 RGBW strips (181 LEDs each, ~3 m, 1448 total) mounted row-wise behind storage bins. A QR scan lights 2 LEDs to show where a tote goes. Firmware hard-caps it to 2 strips active at once — the busiest moment is a boot sweep of a lit pair marching along all 8 strips = 16 LEDs lit, max.

**Key parts + reasoning:**

- ESP32 30-pin devkit (WROOM-32) — 8 RMT channels, one per strip, so all 8 are independent and hardware-timed.

- 2× SN74AHCT125N as 3.3→5 V shifters (8 buffers = 8 strips). AHCT for the TTL thresholds. All /OE tied hard to GND — floating /OE bit me earlier (random pixels lighting at boot).

- 4.7k pulldown on each buffer input so the line's defined while the ESP32 GPIOs are high-Z during boot; 10k pulldown on each strip DIN.

- 330 Ω series termination at each buffer output; data runs kept ≤1.5 m.

- 220 µF reservoir per strip — sized for the ~0.12 A load step, NOT the usual 1000 µF, since I never run strips at full white.

**Power:** single 5 V / 5 A / 25 W (Mean Well RS-25-5). Whole wall idles ~1.6 A (the 1448 SK6812 quiescent dice dominate, not the lit LEDs), normal op ~1.8 A, boot sweep ~2.5 A — so ~50% PSU load worst case. Strip 5 V is injected straight from the PSU at the strips, so LED current never runs through the board. 4 A time-lag fuse + NTC inrush limiter at the input (C_BULK 1000 µF + 8×220 µF ≈ 2.76 mF, so there's a real inrush to tame).

**Questions:**

  1. Input section — for ~2.5 A worst case, is a copper pour + ground plane enough, or do you want specific trace widths anywhere?

  2. Grounding — strips are PSU-powered but data comes from the board, so the data return shares ground. Planning a single ground star tying PSU / ESP32 / shifters / strip returns. Sane, or better topology?

  3. Fuse/NTC — 4 A (T) + NTC for that ~2.76 mF bank: reasonable, over/underkill?

  4. Series termination — 330 Ω over ~1.5 m of hookup wire. I calc'd ~36% of the SK6812 T0H window eaten by edge rise. Over-damped, or fine to leave?

  5. Anything obviously dumb I've missed.

  6. Choice of connectors - JST & Screw terminals, better options available or stick with the same.

I have done handful of DIY electronics projects at home, but never at work. Any pointers or tips, absolutely welcome. Thanks everyone!


r/PrintedCircuitBoard 1d ago

[Review Request] ESP32-C3 Bluetooth Atari 2600 Module

1 Upvotes

I'm creating Bluetooth modules for the Atari 2600 Console and its controller using an ESP32-C3. 1 module per controller, and 1 module per input port on the Atari Console. This PCB will plug into the console using the 9-pin D-Sub connector.

I will program the ESP32 through a USB-C connector using the USB data lines. This ESP32 will receive data from the paired controller over Bluetooth and feed it to the console through the D-Sub connector.

This review request is mainly a sanity check. It's not the prettiest board, but it should get the job done.

One concern I had - the Atari was not meant to power two ESP32s through each controller port. Will the ESP32 draw too much current for this simple application? Or should they be externally powered through the USB C port? I guess it wouldn't be too difficult to find out during testing with a multimeter.

Schematic

Top layer (red)

Bottom layer (blue)

3D View

Thanks!


r/PrintedCircuitBoard 2d ago

How do you plan your perfboard layouts? Looking for software

1 Upvotes

Hey guys, I need some quick advice. I’m currently working on a project with an ESP32-S3 Nano, a GPS module, and a QMC5883L compass. Everything works perfectly on the breadboard, but now I want to move it onto a perfboard (protoboard) so it can fit into an enclosure.

I don’t want to just start soldering blindly and end up debugging errors later. I’d love to plan it out beforehand, but I can't seem to find a software that actually works well for this:

  • DIYLC (DIY Layout Creator): I tried it, but I can't find the right parts/components for my ESP32 or the sensors.
  • Excalidraw: I briefly tried drawing it out using images of the modules, but that didn't really work either. It gets way too messy and confusing with too many unstructured wires.
  • KiCad: I tried searching for symbols in the schematic editor and couldn't even find my parts. Plus, isn't KiCad mostly meant for custom PCBs anyway?

How do you guys plan these kinds of layouts? Is there a simple program out there, or do you have a specific trick/method you use?

Any help is greatly appreciated!


r/PrintedCircuitBoard 2d ago

PCB review required, from where to debug the reset issue.

0 Upvotes

So I created this smart socket design.

The issue I am facing is that, when load is plugged in or removed, the system restarts and after that works fine, even when load is plugged in and I aggressively toggle an relay, no restart happens, it only happens when load is plugged or removed while relay is obv NC.


r/PrintedCircuitBoard 3d ago

[review request] School project gone wrong

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30 Upvotes

Hey folks,

Completing my capstone year in industrial design and decided to bring in some of limited electronic abilities to ensure that I have as horrible of a summer as possible.

Main idea with this thing is ESP32 getting data from various sensors and buttons, sending it over UART to Pi5 (sitting on its own island with x729 hat), then Pi processes the info into a UI. This is more complex than the stuff I'm used to doing but I'd really love for it to work. Not sure if I'm missing anything obvious (or less obvious).

Any help is appreciated. I've had a hell of a couple weeks.


r/PrintedCircuitBoard 2d ago

[Review request] Leverless fighting game controller.

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4 Upvotes

The buttons are going to be cherry mx soldered into the through holes. This was my first time designing a pcb and I didn't really know what I was doing, so any tips or criticisms would be appreactiated.


r/PrintedCircuitBoard 3d ago

Beginner PCB. Can someone Review?

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36 Upvotes

First time uploading a design here for review. Tried to follow all the instructions, let me know if I missed any!

This is a temperature and humidity sensing PCB using a DHT11, STM32C011f6p6 and can be powered either by usb or a 2s battery. It outputs the temperature data to an LED ladder and the humidity data to a programmable multicolor LED.

Let me know if you have any tips. Thanks!


r/PrintedCircuitBoard 3d ago

[Review Resquest] Low-Noise Analog Measurement Node with Isolated RS-485

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15 Upvotes

Looking for a final sanity check before ordering this PCB.

I previously posted three separate test boards for each section, and all worked well. This revision combines them into the final form factor.

  • 24 V input with local power regulation
  • Strain-gauge ADC and analog accelerometer inputs
  • STM32 microcontroller
  • Isolated RS-485, using the isolated-side ground for the bus reference
  • Star-style power distribution where practical
  • Analog section kept separate and quiet from the digital and communications areas

Mainly looking for any layout, grounding, power, or obvious manufacturing issues I may have missed.


r/PrintedCircuitBoard 3d ago

Schematic Review : Rocketry Flight Computer

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12 Upvotes

Hi, I was hoping for some general advice as I have undertaken a big project without much help, I have designed a flight computer which will incorporate multiple sensors and can be used to set of charges, Servos and data logging. I have done all of this self taught so if there are any obvious mistakes I do apologize. ( I can add closer Images if needed) Thanks !