ESP8266

Project: ESP8266
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State	Active
Members	Prodigity, Da Syntax, xopr
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Description	Playing around with cheap wifi modules
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NOTE

For the ESP Egg Salad programmer, see ESP^2

programming the ESP8266

hardware: using the ESP^2

NOTE: the used serial connection is 5v (but has some resistors), which is officially not supported

NOTE2: currently, there is only an 8-pin header for the ESP-01

• before connecting the ESP^2, plug in the ESP-01 (note the markings)
• flip the switch to program mode
• plug in the USB cable
• restore the switch
• upload using your favorite software method

hardware: using an FTDI cable

NOTE: some people state that you can connect GPIO0 to DTR and REST to RTS, but the current settings in Arduino don't support this properly (might be a configuration thing) This would enable automatic program mode for the ESP

Make sure your FTDI cable can do 3.3V!

• connect CH_PD and VCC to 3.3V (use an external power supply as most FTDI cables are not capable of supplying the required amouunt of current
• connect GPIO0 (program) via a momentary switch to GND
• connect REST (reset), if available via a momentary switch to GND (or do a power cycle if you want to start the bootloader mode
• and GPIO15 (if available) via a 10k resistor all to GND
• press both reset (or cut power) and program
• release reset (or restore power)
• release program
• upload using your favorite software method

software: using Arduino 1.6.4

Taken from https://github.com/esp8266/arduino

• Install Arduino 1.6.4 from the Arduino website.
• Start Arduino and open Perferences window.
• Enter http://arduino.esp8266.com/package_esp8266com_index.json into Additional Board Manager URLs field. You can add multiple URLs, separating them with commas.
• Open Boards Manager from Tools > Board menu and install ESP8266 platform (and don't forget to select your ESP8266 board from Tools > Board menu after installation).
• For the ESP^2, the device name (under Linux) is /dev/ttyACM3
• Change the programmer from AVRISP mkII to ArduinoISP
• poweroff ESP (either unplug the USB or pull the device from the socket
• set the switch to prog
• poweron the ESP
• You can now upload your sketch

NOTE: currently, programming the ESP-12E will result in corrupted firmware with all kinds of strange behaviour. This is caused by the esptool that comes with the Arduino ESP8266 package.

There are two ways to circumvent this:

1. Manual upload: In Arduino, click file, preferences and check verbose [ ]upload
   • upload without putting the ESP in bootloader mode so you don't waste any (corrupt) write cycles
   • note the location of the .bin file and use the esptool method
2. add a better working esptool.py in Arduino (which is what xopr did) by changing some files within the ESP8266 package
   • download esptool.py and put it in ~/.arduino15/packages/esp8266/hardware/esp8266/1.6.5-939-g033463a/tools/
   • edit ~/.arduino15/packages/esp8266/hardware/esp8266/1.6.5-939-g033463a/boards.txt and after
   • generic.menu.UploadTool.espota.upload.tool=espota
   • add

   generic.menu.UploadTool.esptoolpy=Serial (python)

   generic.menu.UploadTool.esptoolpy.upload.tool=esptoolpy

   • edit ~/.arduino15/packages/esp8266/hardware/esp8266/1.6.5-939-g033463a/platform.txt and at the bottom, add

   tools.esptoolpy.cmd=python

   tools.esptoolpy.cmd.windows=python.exe

   tools.esptoolpy.path={runtime.platform.path}/tools

   tools.esptoolpy.upload.protocol=esptoolpy

   tools.esptoolpy.upload.params.verbose=

   tools.esptoolpy.upload.params.quiet=

   tools.esptoolpy.upload.pattern="{cmd}" "{path}/esptool.py" --baud {upload.speed} --port "{serial.port}" write_flash 0x00000 "{build.path}/{build.project_name}

   • Now, in Arduino, you have an extra menu option under 'Tools', 'Upload using', 'Serial (python)'

software: using esptool.py to upload binaries

• Make sure you have a binary (for example, download NodeMCU here or do a search for "site:http://bbs.nodemcu.com nodemcu firmware"
• Download esptool.py (and make sure you have python on your system
• Upload using something that says:
  • Linux

    sudo ./esptool.py --port /dev/ttyUSB0 write_flash 0x00000 ../nodemcu_float_0.9.6-dev_20150704.bin

  • Windows

    GOOD LUCK, edit me if you succeeded

  • Mac

    GOOD LUCK, edit me if you succeeded

loading scripts from a webserver

I (Da Syntax) got tired from typing the scripts line for line into the lua console of the nodeMCU firmware. I wrote a little function to load the scripts from a webserver running on my laptop. This way I can just save the script on my laptop and load it to my ESP8266 calling 2 functions ( netload() and dofile("netloaded.lua") )

function netload()
	conn=net.createConnection(net.TCP, 0)
	conn:on("receive", function(conn, payload)
		print(payload)
		file.open("netloaded.lua", "w")
		file.write(payload)
		file.close()
	end)
	conn:connect(8080,"192.168.1.193")
	conn:send("GET /test.lua HTTP/1.1\r\nHost: www.example.com\r\n"        .."Connection: keep-alive\r\nAccept: */*\r\n\r\n")
end

Future plans

• Send mac address of the wifi module in get so the web server can return device specific firmwares
• Put the script between specific tags so there won't be any problems with headers that are added by the web server + gives the possibility to add meta data (e.g. version of script or a signature)
• Create a nice php/mysql webapp to easily manage the scripts per module

sample projects

Here are some sample projects

Webserver serving JSON (Arduino)

This arduino sketch provides a webserver-like interface and provides a json file (somewhat compatible with SpaceAPI) There is a version running in the space in a 'hot' zone, and accessible on http://192.168.1.132

You can find the code here

SpaceAPI (Arduino)

The new SpaceAPI is a combination of some PHP, MySQL, and some ESP modules updating the space state and sensor data. The ESP sketch sketch will have several features like space state switch, indicator, Dallas temperature and other sensors, which can be enabled compile-time.

SpaceState (Arduino)

This Arduino sketch is a web client and will update the SpaceState

You can find the code here

NeoPixels (WS2812 LEDs)

Adafruit's NeoPixel library has support for ESP8266 since the end of June ('15), so it's easy to add your (strand of) WS2812 LED(s) The only downside is, that the 5V logic doesn't accept 3.3v signals by default; there are two ways to get around this:

1. under-volt your LEDs (tested with about 3.75v, and the input logic accepts 3.3v
2. add a level converter.

You will often see a mosfet (BSS138 or 2N7000, which work bidirectional) or TTL logic (like the 74LS245 octal bus transceiver, or just an AND or OR gate), but since we only need a 5v output connected to a high impedance input, we can use an NPN transistor for this. (reference: [1], [2] and [3])

Connect the:

• collector of a bc547 via a 4k7 resistor to 5v
• same collector to the DI of the WS2812B LED (ASCII LED: top VCC, bottom DO) :[ #]: (top DI, bottom, GND) (top view, the # is where the chip is)
• base of the transistor via a 10k resistor to 3.3v
• emitter to your 3v3 output