[Oberon] Project Oberon

[Skulski, Wojciech]

 Frans-Pieter:

Thank you for the posting. it is an interesting topic. I am not an expert in the field of atmospheric research at all. So I searched for " Nova SDS011 particle sensor" and browsed through the article by Hai-Ying Liu, Philipp Schneider, Rolf Haugen and Matthias Vogt in Atmosphere, January 2019. The article can be downloaded from https://www.researchgate.net/publication/330544166

My first though is that it is serious science. I have not assessed all the facts and correlations because I am not an expert in the field, but the work looks solid. The authors did a great amount of work and analysis. 

>From the point of view of the instrument developer I would say "stay away from reverse engineering this thing" because your reverse engineered firmware and software will carry no guarantee it is correct. You will need to spend a very significant effort on characterizing the device with your own firmware and software. It is one thing to make it work, which can be very satisfying. it is an entirely different matter to release the modified instrument and make users believe that it performs as well as the original. The amount of work to achieve the latter goal will be quite enormous. Basically, you will need to repeat the tests described in the paper. This is a substantial effort.

The technical aspect of this sensor is a somewhat separate topic. I cannot say whether the ADC built into the STM32 is good or bad. I presume it is good within the specs, which apparently were sufficient to develop the atmospheric sensor. I do not know the details of its operation, so I am not going to even try assessing the technology. 

This ADC would not be adequate for my applications, which are a completely separate field. So I am not very interested in this chip for my apps, but I am making a note for the future. Perhaps one day I will see a good use for this class of parameters and then I will have a deeper look at the details.

Thank you,
Wojtek

________________________________________
From: Frans-Pieter Vonck [fp at vonck.nl]
Sent: Friday, February 21, 2020 3:53 AM
To: ETH Oberon and related systems
Cc: Skulski, Wojciech
Subject: Re: [Oberon] Project Oberon

Hello Wojciech,

With your physics background, did you consider to take a look at the ADC
converter of the STM32 chips?
Ivan Denisov has made a start with it a few months ago.

STM32F1ADC1.odc
https://github.com/iadenisov/O7/tree/master/Micro/Files

Currently I'm working together with some fast and deep minds of Revspace
to reverse-engineer the Nova SDS011 particle sensor.
It has a stm32 in it and we want to develop a opensource firmware for
it.

The following aspects we need to consider
- The physics in the sensor, Mie scattering,
- the detector circuit,
- the sampling of the measurements by the ADC,
- interpretation of the data
 From you resume I understand you are an expert in all these subjects.

Hacker- and makerpaces all over the worlds are experimenting with the
SDS011 , but the firmware of it is not disclosed.

Obviously we first go for C to get tinker with the hardware , but it
would be nice to give Oberon07 a try too. Also the Blackbox utility that
you have made could be used to interpret the data.

 From what I understand now, most of the work is done by setting the
right bits in function registers. Buffers and DMA can complicate things.


Greets,
Frans-Pieter Vonck