Software Stack

Stacks

Software for Building IoT Devices

PubSubClient, ESP8266Client, ITEADLIB Arduino WeeESP8266

This is the stack I used first, and for quite some time:

• MQTT client: PubSubClient. Regarding the data connection it is based on the standard Arduino Client interface.
• Client: ESP8266Client: This is a library I wrote that provides a Client facade to the ITEADLIB Arduino WeeESP8266 lib. It deals with ESP8266 misbehavior that can't be handled on the ESP8266 level itself.
• ESP8266: ITEADLIB Arduino WeeESP8266. This library is quite voluminous (in example, because of the use of String) and has a few small bugs

AC_MQTT & AC_ESP8266

After dealing with various problems and repairing and optimizing things to a degree I did what all programmers must do at some point: rewrite the whole damn thing :-)

• MQTT client: AC_MQTT. Compact and easy to understand code implementing MQTT operation for QoS levels 0 and 1. Does not reserve buffers and performs only streaming read and write operations.
• "Client": AC_ESP8266Client. This is NOT the Arduino standard Client interface, but a tighter integration between AC_MQTT and AC_ESP8266. While it would have been nice to stick to the Arduino Client interface I found this requires too much of a compromise in terms of excessive memory use and gearing for the method of access (Client is rather serial while the ESP8266 expects he reading and writing of buffers). It deals with all kinds of problems like WLAN and TCP connection troubles and general ESP8266 misbehavior. Depending on the hardware provided it can even hardware-rest or power-cycle the ESP8266 if necessary. It can even power-cycle a router if so required (yes, sometimes a mobile Internet router needs a kick).
• ESP8266: AC_ESP8266. The library only provides access to ESP functions that are needed for MQTT communications. The code is pretty compact does not reserve buffers on its own (though it relies on buffers provided by clients). It provides a callback interface in case some data arrived over an IP connection (no need to poll).

My stack does quite a bit more than the stack above regarding error handling, and it does so with less flash and SRAM memory usage while IMHO being more readable at the same time.

Stacks