wifi sensor board
BOM
| oshpark board | $2.40 | 
| esp8266 | $2.09 | 
| antenna | $0.47 | 
| LM1117 3.3v | $0.04 | 
| usb type b | $1.23 | 
parts total: $6.23
| hw-rev | mac | nickname | versions | |
| FTL 2016-Sep io4] | 5c:cf:7f:14:2f:19 | (oddball power lead) | flash fail 2019-02-13 | |
| FTL 2016-Sep io4] | 5c:cf:7f:15:03:aa | electrical tape gum | PHY 1136_0 pp ver 10.2 SDK 2.1.1 NodeMCU 2019-02-14 | |
| FTL 2016-Sep B io4 | ||||
| FTL 2016-Sep C2 io2 | :45:5f | SDK 200 NodeMCU 2017-05-12 | ||
| FTL 2017-May D1 io2 | 5c:cf:7f:d5:7e:da | first dotstar | PHY 1134-0 pp ver 10.2 SDK 2.1.0 2017-05-05 | |
| FTL 2017-May E1 io | :69:e9 | PHY 1136-0, pp ver: 10.2 SDK 221 NodeMCU 2018-11-18. FLASH FAILED | ||
| FTL 2017-May E1 io2 | 18:fe:34:d4:42:97 | marble16 | SDK 2.1.0 NodeMCU 2017-07-22 | 
Todo
Pinout data
new chip $2.60/each QFN32 5mm
http://www.ebay.com/itm/like/172263272606?lpid=82&chn=ps&ul_noapp=true
http://espressif.com/sites/default/files/documentation/0a-esp8285_datasheet_en_0.pdf
breakout https://pcbs.io/share/zMQDz
2016-Aug-6
2016 Sep esp-square boot ' ets Jan 8 2013,rst cause:2, boot mode:(3,6)'
2016 Sep esp-square download ' ets Jan 8 2013,rst cause:2, boot mode:(1,6)'
2017 fail 'ets Jan 8 2013,rst cause:1, boot mode:(5,7)'
boot device:
    0:
    1: ram
    3: flash
boot mode (x,y); x = [. . . . . GPIO15 GPIO0 GPIO2]
https://github.com/esp8266/esp8266-wiki/wiki/Boot-Process#esp-boot-modes
| mode | 15 0 2 | |
| 1 | L L H | Download from UART | 
| 3 | L H H | SPI Flash boot | 
| >=4 | H x x | SDCard boot | 
reset causes http://www.esp8266.com/viewtopic.php?p=2096#p2112
 reset causes:
      0:
      1: normal boot
      2: reset pin
      3: software reset
      4: watchdog reset
warmup while on 'W' on WARM place board wait until 0:15 turn up heat wait until 1:30
--flash_freq 80m --flash_mode dio2019Mar BOM
SPI Speed : 40MHz SPI Mode : DIO SPI Flash Size & Map: 32Mbit(512KB+512KB)