During looking for a new solution for measuring the water level in my cistern I stumble about the ESP8266 chip. This chip provides Wi-Fi access at a very low-cost. At eBay I found the ESP-03 model with a price below 4 Euro. But now I go back to the roots of my findings.
The ESP8266 is essentially a chip with 32-bit CPU. The specification left many questions open. It’s more like a adverting flyer. But there are two communities around this chip: The first forum is maintained by the chip vendor espressif systems. The other forum is driven by the community who build some cool stuff with the ESP8266.
If you would buy a module you have currently (June 2015) the choise to buy one of the 13 versions. For getting started with the chip I’d chosen the ESP-03 which a bought from a local dealer via eBay. I wouldn’t wait weeks for the first chip if I choose a chinese dealer. I’d chosen the version ESP-03 because I need many GIO pins and would have the Wi-Fi antenna included. I was thinking about version ESP-07 also with many GIO pins and antenna but I was not sure if I can get a module without the DOA issue. So I thought its saver to buy a ESP-03 module.
Regardless the version you choose you get a PCB with the ESP8266 soldered onto the PCB. Also on the PCB is a flash memory chip. But I didn’t find clear information how big the flash memory would be. On a photo found via google I found that for ESP-03 the 25Q40BT chip which has 512KB flash memory is used. Beside these two chips the PCB contains the crystal and some other SMD parts.
For working with the ESP8266 Wi-Fi module I see two general options. You can connect a microcontroller to the UART and communicate via AT commands with the module. But you can also write your own application that runs in the ESP8266 module. There is a SDK available which includes also example code. If you wouldn’t like to set up the build tool chain by your own, you can use a lubuntu virtual machine image where all the stuff is pre-installed.
For now I’m waiting for the arrival of my ordered module and I try to get the example code compiled that’s included in the SDK. After starting the lubuntu VM I found that my german keyboard layout is not supported by default. In the VM are only the english components installed. So I updated the lubuntu to the latest packages and installed the german input language. After that I could compile the example code. But other examples from github are not working. Maybe there is a difference between the espressif IoT SDK and the esp-open-sdk.