NMEA2000-BM280 environmental sensor

Table of contents

• NMEA2000-BM280 environmental sensor
  • Table of contents
  • Description
  • Schema
  • NMEA 2000
  • Librarys
  • Part list
  • Configuration
    • System Configuration
      • Thing name
      • AP password
      • WiFi SSID
      • WiFi password
      • AP offline mode after (minutes)
    • NMEA configuration
      • Instance
      • SID
    • Temperatur source
    • Humidity source
  • Username and password
  • Default IP address
  • Firmware Update
  • Blinking codes
  • Reset

Description

This device measures temperature, humidity, and air pressure. The dew point and perceived temperature are also calculated. The sensor used is a BM280. The values are transmitted as NMEA 2000 messages via an NMEA bus. Device configuration is done through a website, and real-time values can also be viewed on a website in addition to the NMEA bus. On the configuration page, there is a link available for convenient firmware updates.

the BME280 is a versatile environmental sensor that provides accurate measurements of temperature, humidity, and barometric pressure.

• Temperatures ranging from -40°C to +85°C with a high degree of accuracy
• relative humidity in the range of 0% to 100%
• pressure sensor data is in hPa (hectopascals) within the range of 300 hPa to 1100 hPa at temperatures from 0°C to 65°C. The absolute accuracy for pressure measurement is approximately ±1 hPa

In the \stl directory are two STL files. These can be used to print an appropriate housing on a 3D printer.

Schema

NMEA 2000

Depending on the temperature source, one of the following PNGs are sent

• 130310, // Environmental Parameters - DEPRECATED
• 130312, // Temperature - DEPRECATED
• 130316, // Temperature, Extended Range

For humidity the following PGN is sent

• 130313, // Humidity

and for pressure

• 130314, // Pressure

Librarys

• Adafruit BME280 Library
• Adafruit Unified Sensor
• NMEA2000
• NMEA200_ESP32
• AsyncTCP (3.2.6) "
• ESPAsyncWebServer (3.3.12) *
• Webserial (2.0.7) *
• IotWebConf
• IotWebConfAsync (1.0.2) *
• IotWebRoot

* new version and/or new repo

Part list

Part	Value	Supplier
D1	1N4001	Reichelt
ESP1	ESP32DEVKITV1	ebay
IC1	R-78E05-1.0	Reichelt
IC3	MCP2562	Reichelt oder ebay
X1	AKL 057-03	Reichelt
X2	AKL 057-02	Reichelt
X3	PSS 254/4G	Reichelt
	BME280	ebay

Configuration

After the first boot, there are some values needs to be set up. These items are maked with * (star) in the list below.

System Configuration

Thing name

Please change the name of the device to a name you think describes it the most. It is advised to incorporate a location here in case you are planning to set up multiple devices in the same area. You should only use english letters, and the "_" underscore character. Thus, must not use Space, dots, etc. E.g. main_cabin *

AP password

This password is used, when you want to access the device later on. You must provide a password with at least 8, at most 32 characters. You are free to use any characters, further more you are encouraged to pick a password at least 12 characters long containing at least 3 character classes. *

WiFi SSID

The name of the WiFi network you want the device to connect to. *

WiFi password

The password of the network above. Note, that unsecured passwords are not supported in your protection. *

AP offline mode after (minutes)

If you don’t plan to connect the sensor to a WiFi network, you don’t need to configure the two options above. If you want to disable the WiFi after a certain time, you can use this option. Specify how long the WiFi should remain enabled after turning on the sensor. Valid values are from 0 to 30 minutes. A value of 0 means that WiFi is always enabled.

NMEA configuration

Instance

This should be unique at least on one device. May be best to have it unique over all devices sending this PGN. A total of 5 instances are occupied by the device. Starting with the number set here. *

SID

Sequence identifier. In most cases you can use just 255 for SID. The sequence identifier field is used to tie different PGNs data together to same sampling or calculation time.

Temperatur source

One of the following temperature sources can be selected

• Sea water temperature
• Outside temperature
• Inside temperature
• Engine room temperature
• Main cabin temperature
• Live well temperature
• Bait well temperature
• Refrigeration temperature
• Heating system temperature
• Freezer temperature
• Exhaust gas temperature
• Shaft seal temparature

Humidity source

can be one of the following location

• inside
• outside
• unknown

Username and password

Username is admin. when not connected to an AP the default password is 123456789.

Default IP address

When in AP mode, the default IP address is 192.168.4.1

Firmware Update

To update the firmware, navigate to the Configuration page and click on the Firmware Update link. Follow the on-screen instructions to complete the update process.

Blinking codes

Prevoius chapters were mentioned blinking patterns, now here is a table summarize the menaning of the blink codes.

Blinking Pattern	Meaning
Rapid blinking <\br>(mostly on, interrupted by short off periods)	Entered Access Point mode. This means the device creates its own WiFi network. You can connect to the device with your smartphone or WiFi capable computer.
Alternating on/off blinking	Trying to connect to the configured WiFi network.
Mostly off with occasional short flash	The device is online.
Mostly off with occasional long flash	The device is in offline mode

Reset

When CONFIG_PIN is pulled to ground on startup, the Thing will use the initial password to buld an AP. (E.g. in case of lost password)

Reset pin is GPIO 13