Update: ESP8266 based SensorNode V2

I updated the circuit and pcb design of my Esp based SensorNode.

Further details in the github repository.

ESP Programmer

I put together an adapter board to attach a CP2104 board to ESP8266 and provide auto programming mode.

For further details see the github repository.

ESP8266 based SensorNode

In last weeks I put together a Sensor-Node based on ESP8266. The software part provides:

• the standard WiFiMonitor to setup the WiFi credentials
• a web page to configure the connected sensors
• a web service to read the configuration and current sensor values
• the data are published via MQTT in a format to be feed into a influxdb

The following sensors are supported:

• DS18B20 (multiple)
• BME280
• Si7021

SensorNode configuration page

I designed a board to be put into a USB port with a temperature and a humidity sensor. 

SensorNodeUSB circuit

SensorNodeUSB PCB bottom side

SensorNodeUSB PCB top side

More information can be found in the GitHub repo SensorNode.

ESP8266 - Convert from human readable date/time to epoch timestamp in Lua

For my current ESP8266 NodeMCU project I need a Lua function to convert the date/time returned by the DS3231 to epoch timestamp.

Update: I also wrote a function to verify the validity of the input parameter (see this github gist)

Wifi Scanner with ESP8266 + TFT ST7735B (NodeMCU)

After successful connect the ESP8266 with the ST7735 display I want to do more than the demo - so here comes a Wifi Scanner.

Same hardware setup as in the previous blog post.

And here is the source code:

ESP8266 (NodeMCU) + 1.8 Inch TFT LCD Display Modul 128X160 SPI Serial ST7735B

Some notes how to connect a "1.8 Inch TFT LCD Display Modul 128X160 SPI Serial ST7735B IC SD Card für Arduino" to a ESP8266 running with NodeMCU.

You need a NodeMCU firmware with (at least) the modules bit and UCG (with st7735 display option).

NodeMCU custom build options.

[Update] Also SPI must be selected! (Thanks to Lorenz)

Pinout/Connection

The display has a 8-pin and 16-pin interface. The TFT interface in both are the same. You can choose either of the two interfaces for wiring.

     ESP8266 --             DISP             -- ESP8266
     OPTION 1                                   OPTION 2
                 --------------------------
                |      ST7735B 1.8 TFT     |
                |                          |
         GND -- | GND  (1)                 |
         3V3 -- | VCC  (2)                 |
                | NC   (3)                 |
         3V3 -- | BL   (4)         (1) RST | -- GPIO16 (D0)
                | NC   (5)         (2) CS  | -- GPIO15* (D8) 
GPIO16  (D0) -- | RST  (6) TFT     (3) D/C | -- GPIO02 (D4)
GPIO02  (D4) -- | RS   (7) TFT     (4) DIN | -- GPIO13 (D7)
GPIO13  (D7) -- | SDA  (8) TFT     (5) CLK | -- GPIO14 (D5)
GPIO14  (D5) -- | SCK  (9) TFT     (6) VCC | -- 3V3
GPIO15* (D8) -- | CS   (10)TFT     (7) BL  | -- 3V3
                | CLK  (11)SD      (8) GND | -- GND
                | MISO (12)SD              |
                | MOSI (13)SD              |
                | CS   (14)SD              |
                | NC   (16)                |
                | NC   (15)                |
                 --------------------------

*) pull-down 10k to GND

ESP8266 NodeMCU dev board connected to 16pin interface of TFT

ESP8266 NodeMCU dev board connected to 8pin interface of TFT

Test

I use the GraphicsTest.lua to test the connection. GraphicsTest is part of the NodeMCU examples (you have to upload also all GT_*.lua files to run the test).

Flash ESP8266-12/12E

Steps to flash new firmware:

1. (optional) Backup flash

   esptool.py --port port-of-esp8266 --baud 115200 read_flash 0x000 4194304 fw_backup.bin

2. Erase flash

   esptool.py --port port-of-esp8266 --baud 115200 erase_flash

3. Write esp init data (see SDK Init Data)

   esptool.py --port port-of-esp8266 --baud 115200 write_flash 0x3fc000 esp_init_data_default.bin

4. Write firmware

   esptool.py --port port-of-esp8266 --baud 115200 write_flash 0x0000 fw.bin