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PCB design - Question from schematic to PCB | Kicad

feiticeir0

Hi all !

I'm coming to you with, probably, a newby question from PCB design.

I'm trying to design my second PCB (the first one had a flaw that I didn't foresaw and was a bust) and I'm coming to you for a small verification.

I'm trying to design a PCB for the following circuit (from https://randomnerdtutorials.com/power-esp32-esp8266-solar-panels-battery-level-monitoring/:

image

I'm going to use a ESP32-CAM .

I already have the kicad project done - the schematics:

image

and the PCB layout:

image

Now, my question is regarding the wiring from the battery to the two capacitors and then to the ESP32-CAM. Will the wiring, like it is, be the same like in Fritzing design ?

I have this working on a breadboard - but there I wire all the wires on the same rail -

image

Thank you

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  • 0

    Hi,

    Are you sure that B+ and OUT+ are connected together, and that B- and OUT- are connected together?

    On the board in the photo below, B- and OUT- are not connected together, you can see the green and blue arrow pads have copper leading away, they are not shorted. I don't know how those charger chips work, they may not be happy charging a battery which is also being discharged at the same time, as would be the case if those connections were shorted together.

    image

    Also, you don't need to route the ground connection, you can make that one plane. For example, the regulator portion could be done like this (some might prefer the ground plane to be on the top side, for through-hole projects, to make life easier when following traces and making mods).

    Notice that I've added a capacitor on the input side of the regulator too. While it might not be necessary (I don't know), it's safer to at least have that footprint on the board just in case. Plus, since this is a one-off board (or even if it is not, if it's not consumer mass-produced item) it's not worth shaving costs by leaving out that capacitor. 

    image

  • 0 in reply to shabaz

    Thank you !

    I'm not even considering the TP4056 for the PCB - that will be connected to the solar panels. This PCB will only be from output of the TP4056 - it will be connected to the battery holes.

    I'm really more interested on the regulator portion and have the ESP32 so I can swap it in and out,  just in case.

    I could use a GND plane (and I've heard of it), but this is my second attempt at a PCB, so, I'm taking it easy ! Slight smile But I've seen your picture and I understand it. I will call it version 2 ! Slight smile

    But, I loved that you've added a capacitor . Will follow your advice and add one too. Btw, what's should be the value ? 100uF @ 16v (for example) ?

    I'm no expert on electronics and this is way out of my comfort zone.  I'm just trying to have the ESP32-CAM be powered by the sun and last while the batteries have juice.

    What I'm trying to prevent (and something that I've witnessed) is that the ESP32 is turning on and off because the sun is powering the panels, but the batteries don't have enough juice to sustain this. 

    I've been doing tests with one 18650, but probably will have two in parallel - for those weeks without much sun.

    Thank you

  • 0 in reply to feiticeir0

    I'm trying to add a GND zone, but I'm getting the following error:

    <no net> will result in an isolated cooper island..

    I'll just add the capacitor and try to add the zone in a version 2 Slight smile

  • 0 in reply to feiticeir0

    When you add the zone, give it the same net name as the pads that you try to connect.

  • 0 in reply to Jan Cumps

    Zones are a bit odd, until you managed to use them once. Maybe create a project with just Vss, Vdd and two resistors in parallel. Then try to play with zones on the PCB design of that simple example.

    It 'll avoid frustration of learning an advanced concept in a real case. If it turns out bad, start over.

    Zones do work well in KiCAD  once you get the hang of it. I made a 4 layer high frequency switch mode power supply, with almost everything being a zone.

    image

  • 0 in reply to feiticeir0

    Sorry been away from desk all day. Yes, 100uF sounds reasonable. Zones are important so worth experimenting as Jan says with a simple project. It simplifies routing because it's at least one less main connection to (mostly) worry about, and most chips (including the voltage regulator) will perform better with the ground plane. Also, don't be shy to rip up traces and reposition and rotate components if need be. It's very normal to not get the routing looking good in a first pass, and to rip things up and redo, and then it can be great. If you want to watch a video that shows a ground plane zone being done, I can recommend this: https://youtu.be/5Be7XOMmPQE?feature=shared

    It covers everything needed for your project in 50 minutes of video. It is a Kicad 6 video but everything there works with the latest Kicad 8 too.

  • 0 in reply to feiticeir0

    Thank you all for your insights and replies.

    I really love learning electronics from you guys. I'll try a simple project to get more comfortable with zones ! Thank you

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