2018-03-25

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)

2017-01-07

2017-01-02

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).


2016-12-29

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

2016-04-10

ESP-01 + DHT22: Send data to influxdb

My first ESP-01 "system" is running now. It measures temperature and humidity using a DHT22 every 20 seconds and send the data to an influxdb database.


The influxdb is then used by a Grafana instance where I define a panel for the temperature and humidity. Here are the first measurements:


Looks like there where a glitch at about 12:30 - I will have a look how often this happen.
And here is the corresponding ESP code: