Hardware descriptions:

1. ESP8266 Wifi module:

2. Loadcell 5kg:

3. HX711 ADC module:

4. LED RGB W2812B module:

5. Button module:

Hardware connections:

| Arduino pin | Peripherals     |
|-------------|-----------------|
| D1          | HX711_CLK_PIN   |
| D2          | HX711_DIO_PIN   |
| D3          | BUTTON_PIN      |
| D4          | LED_RGB_PIN     |

Firmware libraries:

1. PubsubClient to use MQTT client.

2. HX711 to read gravity from Loadcell 5Kg.

3. Database to access EEPROM from ESP8266.

Firmware configurations:

All configurations can be found in config.h file. We can change some configurations:

1. Change Accesspoint configurations:

#define ACCESSPOINT_SSID	"SmartDock"

#define ACCESSPOINT_PSK	"12345678"

2. Change period time to check internet connection(time in millisecond):

#define TIME_CHECK_INTERNET_CONNECTION 30000L

Default is 30 seconds.

3. Change period time to publish data to MQTT server(time in millisecond):

#define TIME_PUBLISH_DATA_TO_SERVER 60000L

Default is 60 senconds.

Specially, server configurations can be changed in server_config.h:

#define MQTT_API_KEY		  "<API_KEY>"

#define MQTT_WRITE_API_KEY	           "<WRITE_API_KEY>"

#define MQTT_SERVER_ADD              "mqtt.thingspeak.com"

#define MQTT_SERVER_PORT		  1883

#define MQTT_SUBCRIBE_CHANNEL			"channels/<channel_id>/subscribe/fields/<field_number>/<API_KEY>"

#define MQTT_PUBLISH_CHANNEL			"channels/<channel_id>/publish/fields/<field_number>/<API_KEY>"

The channel_id, field_number API_KEY and WRITE_API_KEY we can find in Channels > My Profile in www.thingspeak.com.