[chbot] ESP8266 Wifi module progress

[Richard Jones]

We mentioned the ESP8266 Wifi modules at the March and April meetings. Lack
of definitive documentation combined with conflicting and confusing open
source versions and information were offered as reasons to avoid. So I
picked up the gauntlet and got some modules working eventually. It took
longer than I would have liked but I think it was well worth the effort.
This is what I found...

The ESP8266 Wifi module has a 32bit 80MHz cpu, 96k bytes of user ram, and
512k Bytes of flash. The modules cost me $2.60US each delivered from
AliExpress. I bought the ESP12 because they have the most IO pins available
at the moment, and I have six (one from Yani, 5 from AliExpress). Having
spares means that so far I have not let out any of the grey smoke that is
contained inside :-)

I installed and compiled all support software under Ubuntu 14.04. I used
the esp_iot_sdk_v1.0.1 located on github. An excellent tutorial for
installing the tool chain is here:
http://www.penninkhof.com/2015/03/esp8266-open-sdk/

Much of the ESP8266 example code around the web has makefiles that need to
be re-written or modified to work with the open source tool chain. Some of
the examples required mods to header files and prototypes as the tool chain
has moved on over the months.

I tried to use an FTDI USB dongle to program the modules but it kept giving
me errors. I eventually gave up and used a trusty PL2303 USB to RS232
instead with a 4049 cmos level shifter to 3.3V which worked first time.

An excellent open source hardware and software example of what can be
squeezed into the device is available here:
http://harizanov.com/wiki/wiki-home/three-channel-wifi-relaythermostat-board/
I have the relay board code working with a single 1 wire temperature
sensor. Multiple temperature sensors do not seem to work, not sure if its a
hardware or software problem. Tomorrow I hope to hook up a 128x64 oled
display and install my own web pages.

Is anyone else using these modules? I know Phil wrote an great introduction
here:
http://rancidbacon.com/files/kiwicon8/ESP8266_WiFi_Module_Quick_Start_Guide_v_1.0.4.pdf

Richard
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