ESP8266: NodeMCU Dev Kit Review

ESP32 Development Board WiFi+Bluetooth Ultra-Low Power Consumption Dual Cores ESP-32 ESP-32S Board
Integrated antenna and RF balun, power amplifier, low-noise amplifiers, filters, and power management module. The entire solution takes up the least amount of printed circuit board area. This board is used with 2.4 GHz dual-mode Wi-Fi and Bluetooth chips by TSMC 40nm low power technology, power and RF properties best, which is safe, reliable, and scalable to a variety of applications.

Introduction

I was very excited when the very same group that developed the NodeMcu Lua firmware announced their ESP8266 Dev board. I ordered one from Banggood and yesterday it arrived after more than a month.

Quality

The PCB seems to be well done. The silk screen is yellow as opposed to the blue one the group posted on Github. Besides that they look identical. Solder points look also well done. An interesting point you can observe on the bottom side of the PCB: there is a gap which probably will increase Wifi sensitivity, since the PCB antenna is in this area.

The upper side of the NodeMCU Dev Kit with an ESP8266 ESP12 mounted

The bottom side of the Dev Kit. You can see the gap on the yellow PCB
which probably should improve Wifi sensitivity

Driver Installation

After the first inspection I wanted to attach it to my Mac running Yosemite (10.10). I then opened ESPlorer to see if it would find the Dev Kit but no luck there, the device just didn’t show up. I went back to the NodeMCU Github page and quickly found out, that they used a rather exotic CH340G as chip to connect the ESP8266 with the USB interface. It seems that this chip is a lot cheaper than the FT232R by FTDI that is usually used for a Serial-To-USB adaptor. I quickly found the driver page of the vendor but this was not directly supporting Yosemite. Ray on his esptoy page linked  to these drivers:

The Mac OS X driver has two folders. One for Yosemite and one for the rest. Installation worked like a charm since the drivers are also signed for Mac OS X. Otherwise you’d have to overwrite the security check in your System Settings (Security Tab).
After installation the Dev Kit showed up as
  • /dev/tty.Repleo-CH341-XXXX
  • /dev/cu.Repleo-CH341-XXXX
Strangely only the cu.Repleo device was found by ESPlorer but I could use it to connect with 9600 baud to the AT firmware. Then the next problem came…

Flashing New Firmware

There are two tiny buttons on the board: one labeled “User” and the other labeled “Flash”. I’m not sure yet what the User button does, but when pressed during power up the Flash button makes the device go into boot mode where it theoretically can receive new firmwares.
I say theoretically because it didn’t work at all at first. Everything I tried just caused the following error:

$ python esptool.py --port /dev/tty.Repleo-CH341-XXXX write_flash 0x00000 nodemcu_latest.bin 
Connecting...
Traceback (most recent call last):
  File "esptool.py", line 471, in 
    esp.connect()
  File "esptool.py", line 149, in connect
    raise Exception('Failed to connect')
Exception: Failed to connect

After a while I gave up and used a normal serial-to-usb adapter to connect to the RX, TX and GND pins directly, without using the CH340G. For power supply I kept the ESP8266 Dev Kit connected to my Mac.
After another reset I could program the Dev Kit from ESPlorer and I have to say, it works like a charm. It’s great not skip a few wires just to connect to USB. With the Dev Kit power supply and serial connection is all in one beautiful USB wire.

Practical Use

The Dev Kit is very convenient because unlike some of the other ESP8266 modules it easily fits into a standard bread board. But there the beauty ends. As you can see on the picture the Dev Kit spans over all 10 pins of a normal bread board and covers them totally. To use them you’d have to use U-shaped bread board jumpers, but that means you have to remove the Dev Kit just to set them into the board. Not very convenient… Compared to that the ESP201 has on each side one pin row left..
The NodeMCU Dev Kit compared to the ESP8266 ESP201:
You can easily see that the Dev Kit covers all pins,
whereas the ESP201 has one row left

Summary

The NodeMCU Dev Kit is a useful development board that is easy to use and reduces the amount of external components that other ESP8266 modules require. That the Dev Kit covers a lot of holes on a standard 10 pin breadboard reduces the usefulness significantly, but you might prefer this problem over the free-floating wires that the ESP01 requires.
Please let me know if you find out how to flash the firmware without help of an external USB-to-Serial converter…

Quick-Links

Posted by squix78

51 comments

  1. Observation, you could pull the weather icons from the Weatherunderground server rather than host them yourself. I think they do-not apply any read quotas.

    Did embedding the icons in flash prove to be too great an overhead?

    1. Hi David. If I’m not mistaken these icons are from a 3rd party (which reminds me to put their credits up). So I’d have to host it somewhere anyway. I currently also only use uncompressed bmp format and I doubt that any reasonable person still has them around for normal use;-). And then: downloading has the advantage to be easier to change compared to embedding in the firmware… But it was a design decision. Comparing pros and cons…

    1. Hi Stephen. I plan to upgrade the plane spotter project to the color screen, so yes, it’s definitely possible. Just a question of time:-)

  2. Hi,

    I have a working esp8266 weather but the small LCD only.
    im trying this one as i have the exact LCD lying around. i saw the “settings.h” where values need to be changed. (i.e. wundeground API, country, city, etc).. the only one that i was not sure and I did not see any explanation was the ThingSpeak value.

    May i ask what is the purpose of the Thingspeak value? i tried to view it but I think its a private channel.

    Anyway, i uploaded it on NodeMCU and when i inspect the Serial monitor, i can get to the part where it downloads the pictures.
    Here is the last bottom lines on the Serial.
    There is a line that says “connection failed.”…. Im guessing it has something to do with the Thingspeak..or maybe something else..

    …….(lots of downloding lines here…………..)
    Downloading http://www.squix.org/blog/moonphase_L19.bmp and saving as /moon19.bmp
    Downloading http://www.squix.org/blog/moonphase_L20.bmp and saving as /moon20.bmp
    Downloading http://www.squix.org/blog/moonphase_L21.bmp and saving as /moon21.bmp
    Downloading http://www.squix.org/blog/moonphase_L22.bmp and saving as /moon22.bmp
    connection failed
    connection failed
    connection failed
    connection failed

    Loading image ‘unknown.bmp’
    File not found
    Loading image ‘/mini/unknown.bmp’
    File not found
    Loading image ‘/mini/unknown.bmp’
    File not found
    Loading image ‘/mini/unknown.bmp’
    File not found
    Loading image ‘/moon0.bmp’
    File not foundconnection failed
    connection failed
    connection failed
    connection failed

    1. Hi Glenn,
      The purpose of the Thingspeak channel is to display (say) your own local temperature and humidity. So I have an ESP8266 and BME280 sensor running that reports every 10-mins to thingspeak the current temperature and humidity in my garden. Therefore I provide the keys for my channel and it gets reported on the weather display. Ideally there would be a software (compile time) switch to remove that option.

  3. Please ignore the comment below.
    I was able to solve it. Apparently, the wifimanager didn’t connect successfully to my router, so i had to manually connect and put the static SSID and password.

    So its working now, yey! i can see the pictures and the icons properly.

    im still dumbfounded with the Thingspeak channel in the settings.h.
    May i know if that is really needed?

    1. Hi Glenn, I’m a program newbie and met same message from serial port, but I struggled for long time but cant overcome this issue, do you mind give me some suggestion?

      Thanks!

  4. Hi,
    Is there any chance regarding tutorial how to call bitmaps using WiFi connection?
    I want to prepare own set of icons but I don’t know how to use it in your script 🙁
    As well I have a question reagrding screen refreshing, as I see that is the issue when the time is updated and some pixels are not removed?
    Thanks in advance for help.
    Piotr

  5. Very impressive weather station, works great!
    If it could automatically update summer/winter-time, it would be absolutely perfect.
    Have fun with the beer 😉

  6. I was able to get this running, but wanted to mention a small issue I ran into. (Sounds like the same one Mike McRoberts references.) The bitmaps require more than 1M of SPIFFS, so if you were like me and had selected only 1M at compile time, you run out of space to download all of the bitmaps, and many of the moon-phase bitmaps will fail to download, or will be perhaps truncated or corrupted. I went back and changed to 4M (3M SPIFFS) in the IDE and was able to solve this. Still having a bit of overlay issues with the time updates, but as Daniel mentioned, the code may still need a little work.

    Thanks for all the effort on this…now to add some of my own tweaks!

  7. Hi Daniel,
    i tried to flash the script but i will receiving all the time the following error:
    *******************************
    In file included from esp8266-weather-station-color.ino:34:0:
    C:\Users\Jens\Documents\Arduino\libraries\esp8266-weather-station-color-master/WebResource.h:25:31: fatal error: ESP8266HTTPClient.h: No such file or directory
    #include
    ^
    compilation terminated.
    Fehler beim Kompilieren.
    *******************************
    I added the ESP8266HTTPClient-library to the Arduino 1.6.5 but there is still the same error.
    Do you have any idea what i can make that the script will runing?
    Jens

  8. Unfortunately Banggood.com are no longer stocking the 2.2 Inch Serial TFT SPI Display ILI9341 display! Can it be obtained from another supplier? Or can an alternative be used?

    I would like a bigger screen for my PlaneSpotter project so that I can enclose everything in a case with the lcd screen acting as a box top : )

  9. Dani, excellent! Built this over the weekend (preparing to teach another IoT class this week) and almost worked flawlessly (2.4″ TFT + Wemos D1 Mini). Couldn’t get the WifiManager to connect, tried a few different things then finally went manual mode. The 199: timeClient.updateTime(); would sometimes hang, changed the .h to use “us.pool.ntp.org” instead; didn’t do a lot of troubleshooting, was more in quick-fix mode. Maybe later this month I’ll try incorporating Neptune’s daylight savings code back into this (thanks btw for the link to that). PS will try to get some pictures with the kids doing projects over the session the next two weeks. Regards, Mike

    1. Mike, you stated that you changed the .h to use “us.pool.ntp.org”. What is the path/filename to that .h file?

  10. Dani,

    I’ve been adding some of my own enhancements to your original code for several weeks now, and thought I’d share some of my changes in case anyone was interested. I’ve posted these on GitHub if you’re interested…https://github.com/fowlerk/ESP8266-Color-Weather-Station-v8 .
    This version includes many enhancements to the displays (see the README on GitHub), along with Neptune’s enhancements for daylight savings time. The code could stand some clean-up, but otherwise seems to work well.

    Let me know what you think…I’ll post some photos of the displays when I get a chance.

    Keith Fowler

    1. Hi Keith

      You put some really nice things into the code! I knew that the WifiManager had this configuration UI feature but never got around to use it in my code. Now with your code I have a very nice example to use it;-). Thank you a lot for sharing! I just posted your fotos on Twitter and linked to your repository, I hope you don’t mind.

      I am working ATM on a 2.4″ display with touch. This would allow to switch screens or similar…

      Dani

      1. Dani…I don’t mind at all, in fact I’m honored. One thing to note, which I pointed out in the README on the repo, is that I have added a few fields over the past few months that may (or may not) have made it into the Weather Station library for the Weather Underground functions. Not sure how exactly to go about getting those into the master. (You may even be able to spot these on some of the displays.) I did not put those library changes up on the repo.

        I’d also had my eyes on those touch-screens and had similar thoughts on using them to control the screen displays. I’m anxious to see what you end up doing with it. Your projects always give me more ideas to try ;).

    2. keith, can you ples tell me what i need to download in the the IDE program to set this up there are so many files i do not know what one i need ! thansk

      1. Andrew…yes, sorry for not making this more clear in the documentation. I’ve (mostly) just used libraries that others have contributed and were already referenced in Dani’s examples, but you’re right that the list has gotten relatively long and may take some digging to find all the sources. Give me some time today and I will add the links to the documentation on my Github repository.

      2. I have updated the README on my repository with info on the contributed libraries and links to make it easier to find these. Let me know if you have any other questions.

  11. Hey Dani and Keith, I just tried this out a few days ago and love it. Just wanted to confirm that when I tried to use Keiths’ version, it failed to compile due to the changes in the Weather_Station library. I would really like to try out this version if one of you could point me at the correct library.
    This was my first project with an esp8266 and I am really surprised at how powerful and easy it is to use.

    Kevin

    1. Kevin…yes, sorry, I knew that would bite someone. I really wanted to get the changes merged into Dani’s master library rather than start off on another branch. In the interim, I have uploaded the two changed library files for the Weather Underground components to a separate folder on the repo if you want to download those to (temporarily) replace the original ones in the Weather Station library. That should allow it to compile. Let me know if that doesn’t work for you. Hopefully I’ll figure out the right (permanent) solution to address the changes soon.

      Keith

      1. Thanks for the update Keith,

        I got the new code and everything works great. Now I just have to figure out how to make it work with a bigger screen, maybe 7 inch. My eyes ain’t what they used to be. 🙂

        Kevin

        1. Glad you got it working Kevin…and I know what you mean about the old eyes! I’m right there with you. I’m torn between the compact size and being able to read all the data displayed without my glasses ;). Let me know if you find a bigger option that works well for a reasonable cost.

  12. Dani…just made a pull request on your repository to add some of the changes I had made to your Weather Underground library. Let me know if you have questions or issues.

  13. Dani, I just made another pull request for some new updates to the Weather Underground client library. These include changes to support some additional enhancements I have been working on recently that display weather alerts (as per the WU API call “/alerts”), as well as the addition of probability of precipitation (PoP). I have uploaded a new version to my repository on GitHub that shows these additional enhancements (see the README for further details), along with screenshots.

    As always, let me know if you have any questions or issues, and best wishes for the upcoming holidays!

  14. Hi Daniel. I don’t like the Ardunid IDE because of the lack of debugging with breakpoints. Therefore, I’ve just started with VisualGDB and JLink debugger and ESP8266. I have quite some difficulties.

    Do you have any experiences with VisualGDB?

    By the way: I am situated near Zurich and I like your projects! Great work!

  15. I have been having a lot of fun working through the examples with your weatherstation library. I bought your kit, which was an easy way to get started with the ESP8266.
    I am working through the WeatherStationDemoExtendedDST, for some reason updateData is not firing every 10 minutes. updateDHT is working fine, fires every minute.
    I think this is where the problem is, it isn’t setting readyForWeatherUpdate to true. However, it looks exactly the same as your other examples.
    if (readyForWeatherUpdate && ui.getUiState()->frameState == FIXED) {
    updateData(&display);
    }
    Thanks for any help.

  16. Figured it out. Apparently you can’t attach two events to a single ticker? I created two tickers, and now it works.
    tickerUpdateData.attach(UPDATE_INTERVAL_SECS, setReadyForWeatherUpdate);
    tickerUpdateSensor.attach(60, setReadyForDHTUpdate);

  17. I have problems getting it to run with Arduino 1.8.1, esp8266 2.3.0 board plugin and an SPI display. I have to slow down SPI to 250 kHz, otherwise I get all but pixel trash. But when I set OLEDDISPLAY_REDUCE_MEMORY I get a blank screen.

    Do you know of any problems with given setup? Can you recommend a good working combination of Arduino IDE, ESP plugin and SPI settings?

    1. I am a bit confused: which project are you referring to? The OLED Weather station or the color weather station which uses an TFT? Since you posted this in a Color Weather Station post I assume you are referring to the color code? But why then use the OLEDDISPLAY_REDUCE_MEMORY? Can you share a gist which shows your ino file?

      1. I’m sure, I posted that to “ESP8266: SSD1306 Oled Library Release”. 🙂

        Well, I’m just using your examples for the SSD1306 driver. Using a Wemos D1 mini R2 and “SSD1306Spi display(D0, D2, D8);”

        I had it working some weeke before. In the mean time I updated a lot of software, including IDE and board definitions.

        So, there are few choices left: the software combination I have is broken or D1 or display are broken.

        Can you or anyone else report that Wemos D1 mini R2, Arduino 1.8.1 and esp8266 2.3.0 are working with this SSD1306 library (unmodified)?

        Thank you!

        1. I’m still not sure, if my hardware or software combination is broken. But I finally got it all working. Key was reducing SPI speed. In SSD1306Spi.h we have a SPI.setClockDivider (SPI_CLOCK_DIV2), which means 8 MHz. It seems, the (just my?) display can’t handle that, I get mostly pixel garbage. If I reduce that to SPI_CLOCK_DIV64 (which means 250 kHz), it all works. I can even skip the yields() in SSD1306Spi.h’s display() routine. And I can get some speed back with replacing the SPI.transfer-loop for non-double-buffer cases with “SPI.writeBytes(buffer, sizeof(uint8_t) * DISPLAY_BUFFER_SIZE);”

  18. Thanks for making this template availble in the public domain. It has proven to be very valuable. As an improvemnet, would it be possible to have the NodeMCU pin assignment names on the PCB board, similar to the arduino one.

  19. I am having problems with the Weather Station. First screen (time) works well. Second screen says “N/A C”, Third scrren shows N/As, Fourth screen (temp, humid) works well. I have tried installing the latest github code and it doesnt solved the problem. Any tips?

  20. I have bought the Weather Station on Amazon. It came with a DHT11 in a board with a pull up resitor. I am following the pdf with instructions. When pluging this board, the figure at the pdf looks like inverted. My litthe dht board is (from left to right): data, vcc, gnd. It took me a while to figure out this. Also, by printing the read temp and humid values, I saw half of them come as nan. Any tip for improving this?

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