BME688 sensor

[florian-terisse]

Hi all !

I search an implementation for BME688 Sensor.

Has anyone ever done this?

Thank you :-)

[FDelporte]

I can't find an example for this specific one, but we have examples for other "BME family members"...

https://github.com/Pi4J/pi4j-example-devices/tree/master/src/main/java/com/pi4j/devices
and
https://pi4j.com/examples/jbang/bme280_temperature_humidity_pressure/

[mbuckton]

Hi,

I have done an implementation for it here

https://github.com/Maps-Messaging/device_integration/tree/development/src/main/java/io/mapsmessaging/devices/i2c/devices/sensors

It is in development but seems to work.

Matt

[florian-terisse]

Hi Matt,

That's really kind of you.

First use of this app is to speach messages send by ifttt of a fireman android app (It works).

I want now to play with my raspberry and add sensors, screen, etc.

I'm a beginer... :-)

[My class test is here](https://github.com/florian-terisse/notifs-api/blob/sensors_test/src/main/java/fr/terisse/api/notifsapi/services/SensorsSchedulerService.java

Thank you.

[mbuckton]

Hi,

I cleaned up the logging conflict in your gradle config and excluded protobuf from the device library since it conflicted with the version you are using.

I now see the device initialized and have readings printing out. I will create a PR on your repo tomorrow so you can see the changes.

Matt

[florian-terisse]

Hi Matt,

You are a fantastic guy.
Thank you very much again.

Florian.

[mbuckton]

Push Request created in github for you.

Have fun and let me know how you get on

Matt

[florian-terisse]

Hi Matt,

It work's !! Thank you !! :-)
I search a solution since several weeks and I'm happy you helped me.

I'm sorry to ask you another question.... :-)

The bosh sensor indicate a temperature at 22° and I have another thermometer who indicate 20°.
The bosh sensor temperature is supposed to be correct ?

Or I must adapt the mesure with "levels" ?
"This will mean you will need to experiment with the device to understand what the levels actually mean".

Thanks again.

Florian.

[mbuckton]

Hi Florian,

I have a few temperature sensors and none of them give me the same value, they are close but not the same. It really depends on where the device is located, near the Pi or other heat sources.

The number you will need to experiment with is the resistance value being returned as this is the VOC sensor resistance and varies depending on the gas being detected

Matt

[florian-terisse]

Hi,

Thank you for your response. I suscribe your git repo.
Thank you again for your help (L)

Florian.

[crogialli]

Hi Florian,
I've been using BME680 in my application for a year, and I am also implementing BME 688.
It is entirely possible to read Temp, Pressure, Humidity and gas resistances from plain Java code (I do it, and I can submit my code for that, albeit I have an abstraction layer between the BME68X management and Pi4J so that the code could be not immediately usable). Readings for temp, pressure and humidity from BME68X are astonishingly accurate and quick.

However, I want you to know that it is not possible to get sensible air-quality (gas) estimations in that way. You can get a gas sensor resistance reading, but it is entirely meaningless and random, as a matter of fact. It cannot be reconnected to any air quality measure without the Bosh Sensortec Libraries (see below).

Moreover, I've been reading a BME680 gas sensor "manually" every 5 seconds by setting arbitrary heating patterns for a couple of years now. I'm pretty sure I have damaged the BME 680 MEMS gas sensor since current resistance readings are now very low (1..3K), whilst at the beginning, they used to be relatively higher (15K ...150K). The sensor has always been in the same protected ambient (a boiler room with some natural ventilation hosting a diesel-fueled burner).

To get a correct gas estimation and preserve the sensor's life, the only way I know is to integrate BSEC 2.4.0.0 libraries from Bosch, which implement a few adaptive algorithms for sampling the gas estimates with specific (AI-Calibrated) sensor heating patterns and at specific instants, thus providing reliable indexes and safeguarding the MEMS device.

Integrating BSEC libraries poses a few challenges:

1. the library, written in C, is Bosch proprietary
2. the source is not available; BSEC 2.4.0.0 is provided as a C binary library, statically linked
3. it is unclear at the moment if they provide a 64bit binary for Raspberry Pi4 (I want to run on Rasbian 64)
4. A Python wrapper exists, but not a Java one.

I'm looking into developing a Java (or Groovy) wrapper for integrating BSEC 2.4.0.0 into my app. Should I be unable to wrap it in Java, I will likely implement a call to external C or Python code (disgusting but likely functional, provided that a solution to run on 64-bit Raspbian exists).

BME 68X sensors give exceptional results for their price. I advise avoiding messing with air quality if you don't need it; if you do, you shall find a way to integrate BSEC libraries.

[eitch]

Most probably pigpio initialisation failed means you are running without sudo.

[florian-terisse]

Hi @eitch . Thank you. I tried with sudo but result is same ...