Comments on a metronome schematic and board?

[LouisDong]

I've been working on metronome based on the Atmega328P and the Arduino language, although using a discreet microcontroller chip. It has six high brightness LEDs to indicate the beats, a buzzer, OLED display, some push buttons to control the thing, some more indicator LEDs and a 3,7 V LiPo battery with a 3.3 V voltage regulator, a charging controller and a micro USB port for charging. Before having the first prototype manufactured, if anyone could comment on what I've made so far I'd be very grateful.

My aim was to make the whole thing quite small, so I've gone mostly SMD (0603 for capacitors and resistors, 1206 for LEDs). The important thing for me is the visibility of the beat LEDs (D3...D8), so I may still exchange them for 3 mm though-hole LEDs. Some of the components are hidden under the display, but they're all on the front side of the board; the only thing on the back is the battery and a ground plane. I'll be ordering the PCBs from PCBGOGO and soldering the components by hand.

Images of the schematic and the PCB layout:https://imgur.com/a/jSGhLXI

PDF of the schematic:https://www.dropbox.com/s/8v22ouhbj5olz ... c.pdf?dl=0

ZIP package of the gerber files:https://www.dropbox.com/s/2plinqml14qh0 ... s.zip?dl=0

Thank you!

Edit: One thing I'm especially unsure about is whether I have enough bypass caps around the microcontroller and if they're correctly sized and placed. What I have is mostly copied from the Arduino Nano schematic.

[Garth]

It's pretty clear that you're trying to sell PCBGOGO services here. It's ok though, since at least you're on topic and not giving us unrelated spam like we often have to delete.

I was not able to download the dropbox files without starting an account, which I don't really want to do. You can attach your files directly here on the forum though. It's a little difficult to get the needed detail in the .png PCB view on the imgur page. What is the spacing between traces there? I sure looks like you're too close, for example above the top-center mounting hole. Also, I never have angles of less than 90° in the copper, for reasons of washing the chemicals out of the corners really well in the PCB fab process, to prevent corrosion in the corners. An example of where you have an angle of less than 90° is in the top pad of C5 where a trace exits the side of the pad going down at an angle.

There are several pins of the microcontroller not listed. What are they? Are there more ground pins? Generally you want the shortest path possible from power-supply pins through the bypass capacitors and to ground. If you don't have a ground plane, then take it to the nearest ground pin of the IC.

Another thing is that there's no reason (except maybe the looks) to stick to trace angles that are multiples of 45°. Sometimes putting that limit on yourself makes it harder to avoid design rules violations.