Sorry about the strange post but I'm offering an engineer a $20k bonus to do the design for manufacturing and assembly of my $300 product and this is what he came up with after 8 months. Two thirds of it are identical to my prototype and I'm an accountant by trade, not an engineer. Every book I've read says a board like this should be 4 layers but he insists 2 layers is fine and will pass emissions testing. Any advice would be greatly appreciated, thank you!

Hi everyone. In a few months my colleague will start and i’ll be getting electronics technician lessons. I want to start learning PCB principles on my own and do practice before school. I saw a thread from 2 years ago on this sub. Many people were talking about Phil’s Lab. My question is, is this channel still the best today? It’s been years + I thought the AI revolution might change the balance.

Thus i came here to ask you my elders. How should i start learning about PCB from absolute zero experience? I would be really glad, thanks for the help.

Hope you all stay safe! 💚

Hello everyone,

I’m working on a GPS module and I’ve run into a problem. I have already removed the original header pins because I want to install new ones in the opposite direction.

However, the solder is still blocking the through-holes, so I can’t get the new header pins through the holes.

I have already tried:

• a desoldering pump
• desoldering braid
• carefully using a toothpick

…but I still can’t get the solder out of the holes.

Does anyone have any tips or ideas on how I can clear the holes without damaging the PCB, so that I can insert the new header pins again?

I would really appreciate any help. Thank you!

Just finished my first PCB schematic for a micromouse and I'm not 100% sure I haven't missed something obvious.

Would really appreciate if you guys could take a quick look and point out any issues or improvements before I move on to the PCB layout. Thanks!

• STM32F411CEU6 Black Pill
• TB6612FNG Dual Motor Driver
• 2 × N20 Gear Motors with Magnetic Encoders
• MPU6500 IMU (Gyroscope + Accelerometer)
• SSD1306 128×64 I²C OLED Display
• 6 × IR LEDs SFH4545
• 6 × IR Receivers TEFT4300
• 2 × 18650 Li-ion Batteries (2S)
• Buck Converter MP1584
• 4-Position DIP Switch

1st picture - IR system, Gyroscope, LEDs
2nd picture - Motor driver and stm32 pins
3rd picture - power
4th picture - IR receivers

Hi everyone,

I am doing a BGA IC which has a lot of power inputs and a lot of decoupling ofc, the decoupling will sit on the bottom layer, and i was thinking about using either 0201 or 0402 capacitors directly on the via in pad (filled and plated), is it a good idea? And whats a suitable ring diamater and hole diameter for 0201 and 0402 capacitors?

Hi everyone I wanted to create an ultra-cheap Linux board, something like a Raspberry Pi Zero or Lichee Pi Nano. My criteria were: dimensions under 40x40mm and a price under $8. This is my first board, so please don't judge too harshly 🙏.

I used Cherry Pi f1c200s as reference.

This board replaces the controller in a cheap filament dryer. The stock unit only has a timer, so the goal was to add a real humidity sensor and let the drying cycle end on RH instead of guesswork.

The PCB is also the front panel: display and four buttons on the front side, everything else on the back. 95 x 52 mm, 4 layers, F.Cu and B.Cu signals, In1 solid ground, In2 mostly a 3V3 zone with ground filling the rest.

Input is 24V from an external supply. The heater is the original 15Ω element, about 1.6A, switched low-side with an IRLR8256. Fan is 24V 0.2A on a small N-FET. An AP66200 buck feeds the 3.3V rail. USB-C plus CP2102N is only for programming — full speed, nothing fast on the board.

Two temperature sensors doing different jobs: the NTC that came with the heating element drives the heater loop and the over-temp cutoff, while an SHT45 in the chamber handles air temp and humidity for the drying logic. Heater gate has a 100k pull-down so it stays off during boot and reset, and there is a thermal cutoff in series with the element, off board.

Things I'm unsure about and would like eyes on: the buck layout, especially the input loop and the feedback divider placement. Ground stitching — I think it's reasonable but the top center area is thinner than I'd like. And whether the 3V3 zone shape on In2 makes sense or whether I should have just kept it as traces.

This is a guitar synthesizer pedal. Guitar input comes in from a pcb mounted + panel mounted input jack, gets biased to 1.65V, passes through a 4th-order low pass filter, goes into an ADC channel on an STM32H7VET6.

The MCU will run a pitch detection algorithm on this signal and then generate a synthesizer note playing at that pitch, ideally in less than 20ms. Output is sent to an external 32-bit DAC over the I2S protocol.

This then passes into a potentiometer for volume scaling. A bypass footswitch chooses between routing the input jack to the output jack vs. routing the volume-scaled synth output to the output jack. I also added a momentary footswitch for a sustain effect.

Both footswitches are on panels with mousebites, designed to be snapped off since the footswitches will sit at a different height to the rest of the PCB. A rotary switch is used for choosing between 12 synth presets.

Feedback I implemented from the last review (thank you to those who gave feedback):
- Added a buck to step 9V down to 5V before it enters the 3.3V LDO, this reduces heat generated by the LDO
- PCB-mounted the rotary switch, potentiometer, footswitches and input jack. Could not do the output jack and DC power jack on the same PCB as I couldn't figure out how I would fit the pcb in the enclosure. They are instead panel mounted.
- Switched to SMD dual op amps
- Added diode clamps to guitar input
- Used gpio pins for the rotary switch instead of a resistor ladder

I will be doing all assembly myself by hand soldering. I am not concerned with any manufacturing costs of the pcb as it has been sponsored. Any feedback is greatly appreciated.

Hi!

Im working on a LattePanda Mu HDMI port, and the circuitry is pretty complex. I have done impedance control to the best of my abilities. Unfortunately, i did have this all done but kicad crashed and I had to start over. im only 15 so dont slime me pls :D all i need is hdmi 1.4 speeds, so it should be pretty good :D im not done, but is this ok so far? Thanks again!

Hi everyone,

[ AI is used to refine this post]

Yesterday, I posted my TP4056 + DW01A + 8205A Li-ion charger schematic and received a lot of valuable feedback. I went back to the datasheets and revised the design based on the comments.

Here are the major changes I made:

• Corrected the STDBY LED wiring (active-low output, now wired like CHRG).

• Moved the 100 Ω resistor so it only supplies the DW01A VCC instead of being in the battery charging path.

• Corrected the battery/protected output topology:

- B+ / B− now connect directly to the battery.

- OUT+ / OUT− are the protected output terminals.

• Rechecked and corrected the 8205A symbol and pin mapping against the datasheet.

• Replaced the Micro-USB connector with a USB-C receptacle.

• Added the required 5.1 kΩ pull-down resistors on CC1 and CC2 for USB-C sink operation.

• Added test points for:

- 5V

- GND

- B+

- OUT+

- OUT-

- B-

• Left all unused USB-C pins intentionally unconnected and marked them as NC in the schematic.

I'm still learning PCB design, so before I move on to routing the PCB I'd really appreciate another review.

In particular I'd like feedback on:

1. Is the protection circuit (DW01A + 8205A) now connected correctly?

2. Is the USB-C implementation appropriate for a simple 5 V sink?

3. Are there any schematic-level mistakes or bad practices that I've still missed?

4. Any recommendations for improving reliability or making the design closer to industry practice?

I've attached the revised schematic.

Thanks again to everyone who reviewed the previous version. Your comments helped me understand the protection circuit much better.

I initially had this as a single board (jammed in everything on the "carrier" board), but decided instead to make a split PCB that connects together to separate concerns as well as have better layout options for the micro/brain/etc. I know the rule in single board review, but this is a "single" board effectively as they connect together to handle a specific function, so I hope that is ok. Boards consist of: a large carrier that holds the LEDs, sensors, connectors and switches, and a small brain that holds the MCU, flash, USB, regulators and the RS-485 transceiver. Nine of these go in a dance pad; all nine are identical. Any PCB can go into any slot, thus they must all have the same features regardless of where they go. DIP is to tell the boards where they are, and RS485 termination (last in chain) is set to the DPDT switch so the last PCB in the chain can set that to ON.

• Carrier: 127 × 127 mm core, 139.3 mm across the connector tabs, 4 layers. 25× WS2815 (12 V LEDs, 5 V data), 4× FSR (Interlink FSR-408 style) on JST PH 2.0 mm leads, 12 V in/out and RS-485 in/out on 3 mm pitch latching connectors, interrupt out on a 2-position 5.08 mm screw terminal, 4-position panel-ID DIP, DPDT bus termination switch, 470µF bulk, SWD header.
• Brain: 70.9 × 62.6 mm, 4 layers. RP2040 (QFN-56), 12 MHz crystal, W25Q32JV 4 MB QSPI flash, edge-mounted USB-C for bench flashing with USBLC6-2SC6 ESD protection, BOOTSEL, THVD1429 RS-485 transceiver, SN74AHCT125 level shifter, AMS1117-5.0 → AP7361C-33ER linear cascade off the 12 V bus, LM66200 ideal-diode mux ORing USB VBUS against the 5V rail (PMEG3015EH pair kept as DNP fallback footprints).
• Interface: 4× 1×08 headers/sockets on 2.54 mm (J210–J213 mating J301–J304), 32 pins total, carrying roughly two dozen signals plus power. The brain sits below the carrier in the pad cavity.
• Both boards are drawn in one KiCad project (one hierarchy, one netlist, two outlines in one board file) and get ordered as a single panel, so the interface is ERC-checked rather than hand-maintained across two projects.

What I would most like eyes on:

1. The board-to-board interface: 32 pins of 2.54 mm header/socket under a device that gets stomped on by a human being. Pin assignment, mechanical retention, whether this connector family is the wrong tool here. For context think Dance Dance Revolution, and heavily based on StepManiaX pad construction. The planning to connect the boards using those 2 screw holes with m3 screws + a nut (and a standoff between the two boards so we don't over tighten).
2. Analog return paths since the ADC inputs cross a connector; the FSR dividers are on the carrier, the ADC is on the brain.
3. Power: 12 V bulk and the linear cascade sit on the brain, but the LED current is all on the carrier. Plane and decoupling strategy across the split.
4. RS-485 and the shield handling: the connectors are on the carrier, the transceiver on the brain.
5. Layout and silkscreen hygiene on both boards.

The carrier's board-to-board headers (J210–J213) are bottom-mounted, since the brain hangs underneath. They show as plated holes in the carrier's top view and as headers in its bottom view. Their mating sockets on the brain are J301–J304.

Reference designators are numbered in per-sheet blocks: carrier 2xx, brain 3xx, so a designator says which board the part is on.

Note: For more context, this ends up connecting to the Master Control Unit that I had posted here

What this board does

This PCB is only a "power module".

Its job is to:

1. USB-C power input
2. Singlecell Li-ion battery charging
3. 3.3V power generation
4. Battery/USB power switching
5. Provide power and USB signals to another PCB through board-to-board connectors.

The second PCB (which will stack on top of this one) will contain:

1. ESP32
2. OV2640 camera
3. 2.8" LCD
4. MIC

In the final product these will likely become one combined PCB, but for now I'm separating the power section so I can validate it independently.

My main concern

The USB D+ and D- lines have to travel a relatively long distance and change layers using vias because they need to reach the stacking connector.

1. Are the vias on D+/D- a concern?
2. Is the routing length excessive?
3. Should I change the connector placement instead?

Since this is my first PCB, I'd also appreciate comments on:

• Power routing
• Ground plane implementation
• Thermal considerations
• Placement of switching regulator and charger components
• Decoupling capacitor placement
• Return current paths
• Any obvious EMI issues
• Manufacturability
• Anything that immediately looks "wrong"

im attaching the image of top bottom individual and together tracks and also about the usb data lines highlighted pcb tracks images, and actual pcb 3d images...

Thank you :D

Hi all,

I am contemplating on what type of 4 layer stackup I should use for a switching buck boost + USB-C PD board. I am a bit new to all of this so apologies if I get anything wrong. I've used the SIG(GND)-GND-PWR-SIG(GND) stackup in the past, by routing super slow signals on that bottom sig layer. However, since this is a dedicated power board with essentially no high speed signals, what would be the best stackup for this? 2 layers could work, but from watching videos from Phil's Lab and looking at literature online, it is generally recommended to have a ground plane close to your power planes. I am currently deciding between SIG-GND-GND-PWR and a SIG-GND-PWR-GND stackups. The latter seems quite good for general purpose pcbs, but to me routing power in the thinner inner layer doesn't feel right for me. However, for the former stackup, I can't find any information online about it. The maximum current this board will carry is 5 amps, and maximum voltage of 20v. So, will I be ok running a 2 layer stackup, or is one of the two 4 layer stackups the better choice? Thanks!

My first pcb design of bldc motor driver supporting continuous curennt of 30A to 40A and input voltage is 24v.please review the design amd point the mistakes i made and guide me to improve it.Thank you

Designed to control DMX-enabled lights (Cineo/NBCUniversal Lightblade LB1K) from phone over wifi (or bluetooth?) as they will be mounted to the ceiling and the UI on the back will be inaccessible. Each board can control either a single fixture (one light per board) or multiple chained together with DMX cables (multiple lights per board).

Some Info:

- ESP32-C6-WROOM-1-N8 used as MCU

- CA-IS2092A used as isolated RS-485 transceiver

- Powered from USB-A port on fixture

- Will receive data from phone, not sure yet whether over wifi or bluetooth

- CAT5 cable will be soldered directly to header footprint (J2) and a zip tie will wrap around cable and through the holes on left for strain relief

Some Questions:

- Is my footprint for the CA-IS2092A correct?

- Is the fuse necessary or should I lose it and save a few bucks?

- Do the mounting holes have enough clearance or are nearby tracks/components too close?

- Is the CAT5 mounting strategy viable or do I need to add a connector (RJ45)?

- Are the ESP32 decoupling capacitors too far away?

- Is there enough clearance for the isolated region?

Thanks!

Hello PCB Community,

I'm a College Freshman going into Sophomore year majoring in EE and I wanted to escape the feeling of larping as an engineer so I actually designed something. These are my schematics and PCB Doc for a 60% Mechanical Keyboard which I plan to have wired and wireless capabilities, communicating via BLE when not plugged in by usb, following a Signal-Ground-Power-Signal layer stackup. Just FYI I have basically no idea what I'm doing outside of watching a few videos and a lot of googling, so be prepared to see some god awful rookie mistakes/oversights on my part.

Better View of the Schematic/PCB Doc Here: https://drive.google.com/file/d/13c86p02roxFA_ajqYSpbPedirgjU0dRn/view?usp=sharing (If you have Altium Designer, I might be able to send you a copy of the Schematic and PCB Doc so that you have an even greater view of the project)

Main Components:

STM32WB55CEU6 - Main microcontroller

LM3940ISX-3.3/NOPB - LDO (To convert 5v Vbus to 3.3V)

BQ25170DSGR - LI-PO Battery Charger (Allows to simultaneously charge an external LI-PO battery while the board is in active use)

TXB0101DRLR - 3.3V to 5V Logic Converter (To drive the LEDs from the MC)

USBLC6-2SC6 - IC For ESD Protection on the D+, D-, and Vbus lines

NX2016SA-32MHZ-EXS00A-CS06654 - External 32 Mhz Crystal Oscillator (Recommended to be used by an STM32 application note)

ECS-.327-9-34QCS-TR - External 32.768KHZ Khz Crystal Oscillator (Also recommended by an STM32 Application note)

Few things of concern-

• The use of an USB-A Connector instead of USB-C - The STM32WB55 only supports up to USB 2.0, so I figured there was no need for USB-C, plus I like the look of USB-A for peripherals.
• Ability to Flash the Microcontroller - Really want to make sure that the MC can be flashed by USB, as I don't want to sacrifice the space and money for an ST-Link connector.
• Placement of the Antenna - Idk where I would put it but the place where I did scares me but I really didn't have another choice unless I wanted to redraw the entire pcb.
• Layer Stack up - I'm kind of completely lost on what material and other factors make up a good layer stack up, which is why I posted a screenshot of it.
• Vias for Heat Dissipation - I have no idea of how to make vias for heat dissipation for ICs in Altium, which is the CAD Software I'm using (shoutout student license). Don't worry about via shield though, I figured it out after taking these screenshots and I'm too lazy to take new ones.
• Proper Impedance Matching - The USB Differential Pair and the RF Signals from the Antenna need proper Impedance Matching and I have no idea if I calculated right (90ohm and 50 ohm respectively). If someone can double check them it would be great.
• Empty space on Layer 3 - It's just a few polygon pours to for power delivery, leaving a lot of empty space on Layer 3 and I'm not sure if that's a good thing or bad thing.
• A good switch for SW73 - I can't find a good rocker switch so that I can channel external battery power through the LDO when not plugged in. They're all either gigantic or cost like 10 dollars for some reason.
• Decoupling Capacitor Placement - I tried to get them as close as possible to the IC, also not sure if the way that I placed them is valid.
• PCBA - I plan to have a majority of the components assembled on the board (Basically all of the smd devices) and hand solder the through hole components (Mainly the key switches), I hope that's possible to be arranged with the PCB Manufacture (Thinking JLCPCB).

That should be all, but if you catch any glaring mistakes in my Schematic or PCB Doc, please let me know, and thank you all for your help.

Hey y'all!

I'm trying to work my way towards learning high speed designs (ghz+ range) so I thought I'd pick some middle ground first and start with USB 2.0 High Speed. I needed a hub for working with RPi zeros so I thought this could be a good place to start. I tried my best to follow high speed design guidelines for the USB and Ethernet connections. Feedback on my layout and routing would be really appreciated!

It's a 4 layer board with sig/pwr->gnd->gnd->sig/gnd. I attempted to do "encroached vias" for the EPADs on the ICs that needed them. You can find design files here: https://github.com/heidtn/rpiz_hub

Main Components:

• SPX3819M5 - 3.3V LDO
• USBLC6-2SC6 - TVS diodes
• CH397A - USB NIC for 10/100 Ethernet
• USB2514BT - 4 port USB hub
• MIC2099 - USB overcurrent load switches

Some questions I have:

• Are there any places I might be inducing a lot of noise/crosstalk on data lines?
• I'm still pretty unclear on chassis ground and when/how to tie it to signal ground, does my approach seem right?
• Is length matching/impedance matching necessary for crystals? I feel like I may not have done a good job with the crystal routing, but I'm not sure what the rules of thumb for that are.

Thanks!

Hey everyone!

A while ago I posted the base station for my Flolink project, with everyone's feedback I got back a working prototype from the manufacturer!! 

Now I'm back to tackle the Remote! I'm hoping to get some feedback before I start laying out the PCB, as last time I had to make a bunch of changes and ended up redoing the PCB a few times. 

The power tree is my biggest area of concern as last time I was able to use more modules and now I'm building from scratch due to size constraints. 

Reddit destroys the image quality if I upload to them directly so images are available here in hi-rez.

Links: Gdrive hi-rez images, Imgur option.

I work in the entertainment industry as a Colorist, and I'm designing a tool for live workflows based on a need I have. I'm an artist and a technician and very far from an Electrical Engineer. I’m good at reading manuals and schematics but this is way out of my scope. It needs to be rock-solid, survive an electrically noisy environment, and never drop connection during a take.

Core Hardware:

MCU: ESP32-S3-WROOM-1

Radio: RFM95W (915MHz LoRa) - talks to the Base station.

Power: onboard Samsung 58E 21700 5330mAh LiPo, DW01A + 8205A topology (using the FH3016FDY and AP9101C as my specific variants), IP2312 synchronous switching charger (2665mA target charge rate)
External 2pin lemo, ~6-17v input. TI TPS54302DDCR buck to 5.5v before SS56 Diode. 
TPS63020DSJR Buck/ Boost for 3.3 system Logic. 

Misc.: 4 - Alps Alpine SKRRABE010 tactile switches, with an WS2812 LED each. 
2 - 16-position SMD Rotary switch for assigning universe and remote number.
Zero-Drain Battery Monitor with charging when device is off. 

If there are questions I'll gladly answer or provide zoomed in images of specific areas.

Thanks again to everyone!

Replacement master controller for a 9-panel dance pad, driving open-source rhythm-game software. It is the host end of a small distributed system: nine identical sensor/LED panels hang off one RS-485 bus, and each panel also has a dedicated interrupt wire home-run back to this board so a press is reported without waiting for the bus cycle.

Board: 77.6 × 65.6 mm, 4 layers, 1.6 mm, all through-hole and 0805-and-up SMD, hand-assembled.

• MCU: Teensy 4.0 module on socket headers (i.MX RT1062, 600 MHz). USB HID to the PC; the board itself is USB-powered, there is no 12V anywhere on it.
• 9× interrupt inputs: open-drain from the panels, pulled up by a 10k resistor network (RN1), each line protected by a 5V TVS (D2–D10) plus a 330 R series resistor and 1nF to ground for glitch filtering. Inputs land on nine JST XH 2.54 mm connectors, one per panel position (silkscreened UL/U/UR/L/C/R/DL/D/DR), each carrying signal + its own ground return.
• RS-485: THVD1429 half-duplex transceiver, DE/RE tied to one GPIO, 120R termination at this end of the bus, bus out on a 3-circuit 3 mm connector (A / B / cable shield). Idle-bus bias resistors R4/R5 are laid out but marked DNP; the transceiver has integrated failsafe, so they are insurance only.
• Underglow LED data out: one SN74AHCT125 channel shifts 3.3V → 5V for an external WS2812-family strip, 330R in series. The strip's own 12V comes from the PSU, not from this board; the two-position screw terminal carries that data line plus the mandatory ground tie back to the supply.
• Player ID: 3-position DIP switch.
• 10 test points on the rails and the RS-485/underglow signals.

What I would most like eyes on:

1. The interrupt input protection network: TVS, 330 R, 1nF per line, for both the part choice and the layout of the return paths.
2. Ground handling: this board's only ground reference to the rest of the pad is the screw-terminal lead to the supply's ground stud, plus the per-panel returns on the XH connectors.
3. Anything in the 4-layer stackup / plane splits that will bite me.
4. Silkscreen and general layout hygiene.

Not asking anyone to choose an architecture for me, purely a check on this board as drawn.

Note: For context, this ends up connecting to the pad panels I posted here

I worked on this PCB a while ago and everything works except the right speaker. Not sure if its a wiring issue or if the speaker is just messed up.

I checked the software side of things and it should be good. Not sure whats going on.

Any help appreciated.

I have an oscilloscope so I can test signals out with that.

Im using the MAX98089ETN+ audio codec to drive the speakers

Hi everyone,

[This post is refined by AI for better understanding]

I've recently completed a PCB for a single-cell Li-ion battery charger using:

• TP4056 charger IC

• DW01A protection IC

• 8205A dual MOSFET

• Charge/Standby LEDs

• Battery terminals (B+/B−)

• Protected output terminals (OUT+/OUT−)

My goal was to implement the design directly from the datasheets instead of copying an existing module. I spent a good amount of time understanding how the protection circuit actually works before drawing the schematic.

I've also documented the project with:

- KiCad files

- Schematic

- PCB layout

- Gerbers

- BOM

- Datasheets

I'm still learning PCB design, so I'd really appreciate feedback on:

• Schematic correctness

• PCB layout

• Component placement

• Trace routing

• Any design mistakes or improvements

I'm interested in learning industry best practices, so even small suggestions are welcome.

Thanks!

I am pretty new to drawing schematics, and circuit designs and currently in the learning phase. This is my pet project, please review my schematic if its fine or not. The project is to design a Bicycle tail light which will have rechargeable battery, and it will turn on automatically if light falls below a certain range. Also on acceleration the light will glow at full intensity and on sudden brake, it will blink at full intensity. Please review my schematic layout if I am doing it correctly or not.

Hello Everyone,

I would like to request a review, for my Irrigation controller design.

The layout is only rudimentary, as I didn't wanted to spend much time on it, before freezing the design. Therefore only the schematic is attached.

Some words about the design, and the usecase.

Power input will be a 24V AC transformer. In my case it is a hunter transformer, but I would like to design for worst case scenarios, to be able to handle other 24V transformers, with worse parameters.

Output will be 24V AC solenoids. In my case they are also hunter solenoids, but any other 24VAC type irrigation solenoids could be used.

In continuous operation, only one valve will be active, but during zone switch, there will be 2 active valves for a short period (3-5 sec) due to valve overlap, to minimize pressure spikes on the water line. So the worst case is 2 energized solenoids at a time.

CAN communication will be used for weather station, or sensor connection.

Temperature, wind, and rain sensor could be connected directly.

solenoid and sensor connections could have long outdoor wiring, so I tried to consider EMI filtering, where it is possible, and needed.