@Yves_MARCEL - this is an old topic of mine, and lots has happened since I posted it - I’ve built the Kube sensor around this board and an LED controller, as well. However, I’m now working on version 2 of the board (https://www.pcbway.com/project/shareproject/NodeMCU_v_1_2_Board.html) - which incorporates a lot of lessons I’ve learned since the original design, as well as some new features. One of the features is making the board stackable - so, I can do things like this:
(That is an OLED display and a multisensor board, talking via the I2C header I created to “stack” the boards). My idea going forward is similar to yours, but I basically want to create “daughter-boards” you can stack together to bring in new sensors or devices (like ADCs, LED controllers, AC/DC power supplies, etc…). I need to find some downtime to create the Github repo with all the work I’ve done so far, but I’d love to collaborate with you (and others) to bring new sensor devices into the mix.
As far as your layout, I’ll make a few quick comments:
- Use D1/D2 for your I2C lines (that’s what ESP Easy and some of the other frameworks I’ve used treat as the standard I2C pins.
- I don’t recommend using the A0 on the NodeMCU - the ADC is only 10 bit, and gets scaled down to 0-1v, making for very poor, very noise-prone signal resolution. This is one of the reasons I’m making a board with an ADC1115 (16bit, full 5V range, 4 channels).
- D0 for one-wire is also problematic, since it’s used in the boot cycle (reset pin), so I’d stay away from it
- Stay away from the GPIO pins on the left side of the NodeMCU in general (they’re used for the onboard flash, so they can’t be used for any other function).
And as far as making this into a PCB, I recommend watching some videos on a PCB CAD program - I’ve been using Eagle, mostly because it’s a very powerful PCB design tool (including a decent auto-router and lots of library support for all the different devices you want to put on the board), as well as because it’s free for hobbyists and small business owners (a renewable, 1 year license, basically).
Once you figure out the board design, a fab shop can make your boards for pretty cheap. My favorite is PCBWay, because they’re quick, make quality boards, and are cheap ($5 for 10 boards this size, plus shipping which depends on how fast you want the board in your hands).