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A project log for ESP Stack

Stackable development kit based on ESP8266 module.

jakub-piaseckiJakub Piasecki 07/12/2015 at 11:206 Comments

Yesterday, after 3 weeks of waiting, I got mail from OSHPark with first revision of core board. I'm pretty excited about it because that was first time when I sent something to professional PCB fab. I'm also satisfied with results. Here is how it looks:

I'm still waiting for tantalum capacitors I've ordered almost 2 months ago but here is how it looks assembled:

It's almost perfect, although there are some minor issues to solve. Holes for header should be a little bit wider, and reset button moved closer to signal pins (to make it consistent with all other boards). But that's all. I'll probably fix it later this week, make prototype board and send it to fab (this time I want to test one in China).

Discussions

Mark Kuhlmann wrote 03/09/2016 at 18:04 point

Are the files available anywhere to order from OSHPark or anything? Any extra boards available? I love the stackable small form factor for some projects I'm working on.

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Jakub Piasecki wrote 03/10/2016 at 07:39 point

Glad you like it. You can probably try to look for it on my github: https://github.com/zaporylie/esp8266-esp-stack, but I'm not sure if that repo is up-to-date.

I've been working on smaller version recently - espstack-mini - but it's not finished yet. Here is small preview. I hope to send rev2 to PCB shop right before Easter and try & review ~three weeks after that.

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Mark Kuhlmann wrote 03/10/2016 at 13:52 point

Those look awesome! Are you going to open a separate project for the mini? I'm very interested in following it. 

My end goal is to have the smallest form factor available to plug in to USB ports or a battery (stackable LiPo?) throughout the house and provide feedback or data for home automation purposes. I need them to be small and not very noticeable so my wife doesn't mind :)

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Jakub Piasecki wrote 03/10/2016 at 14:49 point

@Mark Kuhlmann: Thanks Mark!

Layer with USB has integrated Li-Po driver. I made some tests on it with very small, 300mAh Li-Po battery. I was reporting humidity and temperature every 10 minutes and it last for approx. 4 days. 

I'm gonna share files and some code examples but I just can't promise when. Have a lot on my plate right now but I'll definitely let you know!

btw . something you might like: https://goo.gl/OEBh64 :)

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Mark Kuhlmann wrote 03/10/2016 at 17:00 point

Please keep me/Hackaday posted. It's a fun project for sure! The fact you got the battery working for a decent amount of time is really neat.

That Link isn't working for me :(

Do you have a stackable programming board? So the Esp-12e is mounted on one board, but another is stacked to program it over USB for example? 

What I wanted to work on next was a jig to slide in an ESP module into for programming over usb like a Node MCU or Wemos. Something like this mounted onto a dev board:

https://www.thingiverse.com/thing:1333056

When the programming was done you could then install the esp-12e into one of your boards by soldering. The in-field modules with sensors wouldn't need any of the programming hardware to save space/cost on the board. If you had a stackable programming board the same concept applies as long is they all fit in your ecosystem.

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Jakub Piasecki wrote 03/10/2016 at 18:33 point

Oh.. sorry, this link should work: https://goo.gl/photos/cjM6sAS7o5uGAALF7 (i2c oled)

I'm using micro USB to power my stack but also to send new firmware to esp8266. PCB with USB has to sides (see https://goo.gl/photos/Va1iyJVSJzEs2P2X6), one for power circut (including battery connector, usb and li-po driver), the other one for usb2serial bridge with ft232rl on board. It has to be small and easy to solder that's why I decided to use FTDI chip. I'm not fully satisfied with that approach tho, so I decided to move ft232 to separate layer and keep all elements on one top side only - makes it much easier to stack them together. 
Generally I want to program each esp only once over cable, then, if needed, send firmware updates OTA (over-the-air). I've tested that approach with instances of espstack I have at home and it works perfect for me.

rev. 1: https://goo.gl/photos/iPpU1skYrXMMSnNW7
I made that one before Christmas and learned a lot from that one (example projects: https://goo.gl/photos/1edoCcT1qDeD4fEk8)

rev. 2: https://goo.gl/photos/DFNT4d3bBn2s6Qq38
not finished yet but you can "feel it" i hope. general changes:
- elements on one side,
- core board has cut-out for esp12e/f (solder reversely to save some space)
- usb2serial on separate layer, usb D+ and D- connected with pogo pins(!) - has to be situated underneath usb board but we should use it only once in stack lifetime,
- support for gpio9 and gpio10 obsolete (really hard to use them anyway)
- usb-breakout for USB type A: 1. to plug it directly to charger - https://goo.gl/photos/7PTXpMnocVb7KRkd9, 2. for higher currents (especially if you're trying to drive LED stripe or chain - 180 ws2812b was too much :P)
- breadboard adapter - U-shape connector is incompatible with breadboard,
- LDO on power layer (because of cut-out on core)

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