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Thread: Smallest wifi module?

  1. #1

    Smallest wifi module?

    Hello all

    After wading through what seems like 1000 different types/variations of ESP wifi modules, I still have not really found what I am looking for.

    My Teensy based project reads .TXT data off an SD card.
    I would like to add the capability of sending this data by wifi from my PC. Never tried any wifi stuff.
    It's a very compact project, and so I am trying to keep the footprint small.

    I dug out a spare ESP8266MOD module that I have never tried. I will use that for prototyping and getting my head around how this will work.

    But, most of these ESP modules include a whole pile of IO's etc that I really don't need. I don't even need a level shifter or 3.3v regulator.
    My circuit is running entirely at 3.3v already, and I plan to add a second 3.3v regulator just for the wifi module.

    All I am looking for is a basic wifi module that can receive data and transfer that data to my Teensy over serial.
    Or, do all these modules have all their IO's brought out as standard practice?

    In a totally ideal world, the module would not need it's own programming, but I suspect that isn't possible.

    Any advice? At the moment, I expect I am going to have an ESP-01 or similar, with most of its functions redundant.

    Thank you

  2. #2
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    The ESP-01 seems like a good fit.

  3. #3
    Senior Member+ MichaelMeissner's Avatar
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    I recall one horse/pesky products had a module that mounted directly on top of a Teensy 3.2. In looking at it, only the Teensy 3.2 would be able to use it directly, and there is only 1 left in the store:


    It also looks like he has another module that would work with all Teensy's since it uses Serial1, and the ground/3.3v pins are in the same location:


    But in looking at the sizes of the ESP-01, if you don't need it mounted directly on the Teensy, some of the ESP-01's looks like they would be a good fit.

  4. #4
    Senior Member+ Frank B's Avatar
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    There must exist smaller chips.. some smart wrist watches have WiFi & Bluetooth, too.

  5. #5
    Senior Member manicksan's Avatar
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    ESP-09 is the smallest I have seen measuring (10x10mm)
    but it's needing a pcb to make the mounting easy,
    it have enought pins for a microsd-card
    and the sdcard could probally be on the back of the custom pcb.

  6. #6
    Senior Member+ defragster's Avatar
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    This has a very tiny minimal board - An ESP32 PICO chip. Programmable with Arduino and pins can be setup for UART RX/TX AFAIK.

    It expects 5V - has a USB connector for programming and power. About the size of a quarter.

  7. #7
    Senior Member+ Frank B's Avatar
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    infra-red builtin. cool.
    good night.

  8. #8
    Thank you for these suggestions, I will look into those further.
    I have a PCB for this project, and the second version will have the wifi, so I can easily put the correct footprint on the board for the wifi chip

    It's going to be using Serial 2, but that isn't an issue

  9. #9
    After a quick Google, it turns out that ESP-09's are impossible to obtain easily (in the UK anyway).
    The other options listed above are hugely expensive.

    Found this...

    https://www.mouser.co.uk/ProductDeta...norwcu2ADV3g==

    I am going to get a couple and have a play I think

  10. #10
    Senior Member manicksan's Avatar
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    They are available on ebay

  11. #11
    Yea, trying to avoid Ebay. Nothing but scamming Chinese crap these days

    But just had a look out of interest and there were none

  12. #12
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    LCSC has a number of modules. Generally in the $1-$3 range.

  13. #13
    Senior Member manicksan's Avatar
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    there is this one (it was down in the search result, there was alot of crap above)
    https://www.ebay.com/itm/ESP-8266-WI...r=670839725981

    it's from a big seller that has good reputation, I have bought alot from there and had no problems.
    (I'm not promoting that seller at any way just giving you the alternatives).

  14. #14
    Senior Member manicksan's Avatar
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    or you could just buy the bare chip and the required flash-memory
    + some external components, and make it a absolute minimum design.

    there is also ESP-05
    better to look yourself
    Ai-Thinker modules section @
    https://en.wikipedia.org/wiki/ESP8266

  15. #15
    Senior Member manicksan's Avatar
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    ESP-12E is the best because it have "32Mbit" flash = 4MiB (4*1024*1024) bytes
    and have built in antenna.

    ESP-07 have a external antenna connector, the same found in wifi-routers and laptops.

    none of the Ai-Thinker modules have built in regulators, of what I know.

  16. #16
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    Not wanting to push the Chinese disti LCSC.com but they have ESP-01, ESP-07, ESP-07S, ESP-12E, ESP-12F for good prices and volume discounts. You can get them via DHL or UPS for quick delivery - typically 5ish days to the US. https://lcsc.com/products/WIFI-Modules_939.html. Best I can tell, LCSC doesn't knowingly sell counterfeit products.
    Last edited by PhilB; 12-18-2020 at 10:10 PM.

  17. #17
    Thanks all. I am wading through all the options.

    My PCB is a custom affair, and has space left ready for a wifi addition. Whether I simply put a header on the pcb for a pre-made module, or build it from scratch, I am not sure yet.

    I still have to get my head around how the heck to program all this stuff yet. Not all that clued up on anything network related.

    I already use JLCPCB for my pcb supplies, so LCSC isn't a bad shout, as it's part of the same company.

  18. #18
    OK. Wow, this is going to be harder than I thought.

    Does anyone have any suggestions for a TOTAL IDIOTS guide to ESP8266 stuff?

    From what I can gather, I need to set my ESP8266 as a client, and then have it sit there and wait for data.

    I then need to figure out how to send that .txt data from my PC to the ESP8266 via some kind of medium (but what that would be, I am not sure yet).
    I am thinking I will need to brush off my Python from the bookshelf and maybe build some kind of Windows based front end, where I can select the .txt file off my computer.

    Hmm

  19. #19
    Senior Member+ Frank B's Avatar
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    Simplest is to flash the AT-Modem-Emulation. On many modules it's already flashed when you buy them. So with a bit luck you have to flash nothing.
    Google should know should be many tutorials how to use AT-Commands and modems. There is a description how to use this mode on the Espressif-website, too.

    And, please, If you have problems, ask them.. not here This is not a Espressif-forum

  20. #20
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    Quote Originally Posted by SteveSFX View Post
    I already use JLCPCB for my pcb supplies, so LCSC isn't a bad shout, as it's part of the same company.
    JLCPCB has ESP-07s and ESP-12S in their library and, surprise, in stock. They also have a bunch of Espressif modules (and in stock, too!). This looks to be a fairly recent addition. We'll see how well they maintain stock on those. Interestingly, their prices are LOWER than LCSC. Go figure.

  21. #21
    Senior Member manicksan's Avatar
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    I have a project that basically is a TCP-UART bridge
    It works in server mode where a client connects to.

    It uses TCP port 8200 for the serial data
    and TCP port 8201 for the serial config
    the defaults are:

    115200baud
    8databits
    no parity
    1 stop bit


    the config commands are (example):

    baud115200 set baud to 115200

    cfg_[databits: 5 6 7 8][parity: (N)one (E)ven (O)dd][stop bits: 1 2]

    cfg_8N1 as above 8 databits, no parity, 1 stop bit
    cfg_5N1 5 data bits, -||-
    cfg_8E2 8 data bits, Even parity, 2 stop bits


    all config commands ends with newline \n (in hex 0x0A)
    and is applied directly after command is received

    available at
    https://github.com/manicken/esp-pulled_ota-wifi_manager

    it also contains a OTA that pulls new updates from a server.

    and it uses WiFiManager from https://github.com/tzapu/WiFiManager that is used to config the First time WiFi connect.

    there is also a WS2812 controller in this release but that can be completely removed.

  22. #22
    Senior Member+ Frank B's Avatar
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    Seems to be very similar to the "AT-Mode"?
    I guess you made some things different, or better.

  23. #23
    Senior Member manicksan's Avatar
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    Except in AT mode you need to initialize the wifi module every time the connected device starts.
    Also my implementation is completely transparent except for the requirement of ending every message with a linefeed 0x0a (this have I made to make the messages sent/received "whole")
    This transparency makes it possible to send debug messages from the connected device without needs to initialize it with at-commands.
    The extra WiFimanager makes it possible to just program a bunch of esp modules and then throw them at different project that already uses UART for comm, and make them very easy to control/debug wirelessly. All you need is a TCP client.
    I could add persistent serial config, so that is only needed to be configured for one project. Also it could contain a webpage where the config is done, plus maybe a page where messages could be sent received to/from the UART. All without any need to use any special library on the connected "UART device"

  24. #24
    Thanks all. Seeing as 2021 is lining up to be the same as 2020, I have plenty of time to get my head around it all.

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