KeeYees 3pcs ESP8266 ESP-12E Development Board WiFi WLAN Wireless Module CP2102 for NodeMCU for ESP-12E for Arduino

These things are great. There's a few available GPIO pins and one analog pin. They have more flash than some other versions, so I was able to put a whole web server with OTA updates where my friend's ESP8266 couldn't run it due to lack of memory.

I recently learned how to connect a variety of different types of inexpensive sensors to a NodeMCU ESP8266 and use its Wi-Fi capabilities to transmit sensor information to other Wi-Fi connected operating systems like Android and Windows etc. These little NodeMCUs are awesome and have been very reliable. I have used at least a dozen of them in different small hardware projects. None of these MCUs have failed yet. Some of the projects that I have used them in include:1. Use a motion sensor to automatically turn my desk fan on and off when I sit down or leave my desk area. That project used NodeMCU, heat sensor, relay, fan, lcd display2. Use a DC volt sensor and NodeMCU to send messages to my cell phone when my car battery is weak. That project used DC voltage senso, NodeMCU, IFTTT technology to get text msg to my cell phone.3. Use switch and NodeMCU to send message to my cell phone when yard gate is opened and closed.4. Used weight scale sensor with NodeMCU to weight items ranging from cotton ball to bowling ball.5. Used Text-to-Speech module with NodeMCU to create a Voice Server so my various NodeMCU projects can use Wi-Fi to send messages to the Voice Server to speak.6. Use temperature probe and NodeMCU to create a thermo logger that records temperature changes on a microSD memory card and can transmit the temperatures in a web page etc.It is fun and fairly easy to create a variety of different types of smart switches using different sensors, relays and these NodeMCU ESP8266 chips.

This is my first time buying anything like this. I'm doing a small project involving an 8x8 LED matrix and running a server on the ESP8266. There are lots of code examples on the internet. I have already successfully connected to my local wifi. It is nice that this comes with 3 boards even though I'm not using all of them because I'm a beginner and could potentially screw something up. Also, the cost is surprisingly low considering what these can do.Here are the steps I took to get this thing up and running:- Download and install Arduino IDE (running it on Mac OS Catalina)- Download and install the driver (Please see the back of the dev board which specifies the correct driver to download. Just Google search for it).- Download the ESP8266 board library- Plug in the ESP8266 via micro USB (this provides the 3v power required. No other power source needed).- Write code and compile/upload it via the Arduino IDE. Note: I ran into an issue where python3 was not found during compile time. I had to install it via homebrew and even then I was still having issues. I recommend googling troubleshooting steps if you have this issue. I eventually resolved the issue by adding something to my bash_profile.- The code you upload will instantly execute as soon as the upload is finished. Anything you place in setup() will run once before anything else runs. Anything in loop() will keep executing over and over after setup runs. This is the common pattern for Arduino boards.Recommendation: Get a breadboard and some jumper wires which makes it much easier to connect components to the ESP8266.

This product is sold as a NodeMCU Lua board, and while the board itself is based on the NodeMCU board, it does not include the NodeMCU Lua firmware. In fact, the firmware includes no Lua interpreter at all, just the stock AT firmware from the ESP8266 module. This caused quite a bit of confusion when I first hooked it up and tried to follow the instructions written on the board itself.Although the seller does provide working instructions for getting the board to work with the Arduino IDE, that has absolutely nothing to do with "Lua". This is like selling a MicroPython board without MicroPython firmware (or even instructions on installing that firmware). One is supposed to include the other. The seller really should remove the word "Lua" from the title since the product is sold without a working Lua interpreter. This is a bit disappointing since it only takes a few seconds to flash the free and open source NodeMCU Lua firmware to the device. If I purchased these modules from eBay or some other sites, I might expect this lack of attention to detail, but not from an Amazon Prime seller. If I were just getting in to IOT and purchased these boards because they were supposed to be an easy way to get started, as the NodeMCU Lua board/fw were marketed as, I might easily get discouraged when I got "ERROR" every time I tried to type a command in the serial console (which turned out to be because the stock AT firmware was installed instead).That lack of detail discourages new makers. If you are selling a product as working as a specific way, and that includes selling a product that has written instructions on it (as this does on the bottom of the board), it should darn well work as expected. It costs less than a minute of time to flash the firmware and no money whatsoever.I was going to give three stars, but the seller did include working instructions for Arduino, so I will consider that as an attempt to make the product workable for the buyer, but considering how little of an investment it is to flash the firmware for the seller, and how much time that would save a new maker who doesn't know how to flash these devices yet, I have to dock a star for lack of attention to detail.