Flashing new NodeMCU Lua firmware to Adafruit Huzzah ESP

Adafruit delivers the Huzzah ESP with NodeMCU 0.9.5, which is pretty old.

So I was thinking of a newer version. The process is pretty well described on nodemcu.readthedocs.org. Unfortunately it also says

The address for esp_init_data_default.bin depends on the size of your module's flash. ESP-01, -03, -07 etc. with 512 kByte flash require 0x7c000. Init data goes to 0x3fc000 on an ESP-12E with 4 MByte flash.

After digging through Adafruit docs (they do not explicitly mention the type of ESP) and also looking at the output of node.info() I figured out that the Huzzah ESP has an ESP12 with 4MB

I got my self a new image from the awesome on demand build service and then flashed it like this:

$ python esptool.py --port /dev/cu.usbserial-AI02CSDU \
   write_flash 0x00 ../nodemcu-master-15-modules-2016-02-18-08-33-47-integer.bin \
               0x3fc000 ../esp_iot_sdk_v1.4.0/bin/esp_init_data_default.bin
Connecting...
Erasing flash...
Took 2.12s to erase flash block
Wrote 423936 bytes at 0x00000000 in 45.8 seconds (74.1 kbit/s)...
Erasing flash...
Took 0.10s to erase flash block
Wrote 1024 bytes at 0x003fc000 in 0.1 seconds (85.4 kbit/s)...

Future updates of the firmware to newer versions no longer need to flash the esp_init_data_default.bin file.

Sending IoT sensor data to Hawkular-Metrics via MQTT

The other day I was writing about 'RHQ-Metrics and Grafana' and was describing how you can incorporate data from other system management agents.

Fast forward a bit and Raider is now called Twix and RHQ-Metrics has morphed to Hawkular-Metrics under the Hawkular.org umbrella.

Recently I have also been playing with Arduino and Co. and got myself also an Adafruit Huzzah ESP8266 board. This is a breakout board with the ESP8266 microprocessor on, that has a bunch of IO pins and built-in WiFi. With the default firmware it is programmed in Lua.

Huzzah on breakout board

While one can program the ESP from the Arduino IDE, I thought to give Lua a try (also to get a feel for the difference to the WiPy, that also comes with Python as a high level language). What is nice with the ESP and the NodeMCU firmware is that it already comes with support for networking, 1-wire, MQTT and more out of the box.

To get started I took the hello-world of IoT-sensors and hooked up a DS18B20 OneWire thermo sensor (for those old enough, I did that in the past with RHQ) up to the ESP and then have this communicate to a MQTT Broker (mosquitto).

Setup diagram

As said before we have with Ptrans a universal protocol translator that can be used to feed data from collected, ganglia and others into Hawkular-Metrics. I've taken that and added support for MQTT (in my personal repo for now). Ptrans will now connect to a broker and listen on the '/hawkular/metrics' topic for data that needs to be in graphite format like

path value [timestamp_in_s]

The timestamp is optional, as in my case I was not able to get any real time clock data from the micro controller (there seem to be variants that have a clock on board).

To see the data that is coming from the device I can just run

$ mosquitto_sub  -t /hawkular/+
16617927:40.176.91.120.5.0.0.125 24.625
16617927:40.176.91.120.5.0.0.125 23.9375
16617927:40.176.91.120.5.0.0.125 23.8750

So here NodMCU with ID 16617927 and thermo sensor 40.176.91.120.5.0.0.125 is reporting around 24 deg Celsius.

I will post more on the topic in a laster posting.

References:

• A simple connected object with NodeMCU and MQTT
• NodeMCU documentation
• MQTT: Building an Open Internet of Things (in Arduino lang)
• WiFi Temperature Sensor with NodeMCU/ESP8266 (in Arduino lang)
• MQTT Ruby Gem