Thank you so much and thank you for staying. I know that I'm keeping you up from your beer,
which will be quite lovely and with a gnarly piece of software and hardware, let's say.
So I'm Lily and this is a part of my PhD work that I completed a couple of months earlier.
I'm a researcher in astrophysics and atmospheric physics and what we did with a couple of folks
back in where I'm coming from, Greece, we made a miniaturized sensor that's used to measure
the electric field strength in the atmosphere and I'll show you in a bit. So a brief agenda of
the presentation, so I'm going to do a bit of an intro and discuss a bit the scientific question
that was posed in our minds and that attracted all the funding for this research to be conducted
and then why we chose open source, which is self-explanatory, let's say for that case,
the sensor assembly and a few testing bits from the sensor, some observations from scientific
campaigns that we did throughout all this period and then our data sharing platforms and what's
next and what we hope from the sensor. So a lot going on here but what I want you to keep in mind
is that we're coming from a field of, let's say again, atmospheric physics and what we were seeing
throughout all the years of science is that our experimental data were showing that particles
and particularly ones coming all the way from the Sahara dust particles were transported all the
way towards central Europe most of the time and we are all the way from the Atlantic so we couldn't
figure out why that was happening and we couldn't because our models and our forecasting models
couldn't depict this change. So we were hypothesizing that these particles are moving within a fairly
dynamic system which is our atmosphere and that we have this vertical electric field that's within
the entire spectrum of the atmosphere and as they were moving within there was some electric force
most probably that would act on the particles and make them to, let's say, float within the atmosphere
or negate the gravitational force that was acted on the particles and then another, let's say,
after effect of these electrical forces could be that it would orient the particles on the vertical
direction and that would give them even fairly more time within the atmosphere which was another
part of my research back in the PhD days. So in order to have and collect all the data that we
could possibly have for our hypothesis we needed to do some measurements from ground-based sensors
but we also needed and found that the best practice to do was to launch balloons over in the atmosphere,
lower atmosphere with atmospheric electricity sensors and acquire the data that we needed within
the layers of the dust particles. So could we verify our hypothesis through the observations and
then we needed new developments in order to do so? So the only way was that to do all these launches
that I talked about before. So let's say why we went for the open source in terms of, you know,
all the traditional academic structures that do not allow the scientists to form collaborations
and they did not foster, many times they did not foster collaborations between open source
practices and then there's this concern in terms of the researcher personal status and
recognition and that all the open source work that's been done doesn't get recognized as it
should be and again then there are these biased reward systems that fog, let's say, the perception
of the researchers and what we wanted to do is exactly that challenge and create transparency
through our work and what we found up till then concerning the specific sensors was unfortunately
fairly closed so we had a couple of projects which were depicted from publications, you know,
the traditional system of the academia to present their results and these were for the left-hand
side they were not tested on these balloon-borne platforms that we needed them from and they were
most of the times sketchy and there were nonexistent schematics at all in terms of the sensors
which was pretty bad and then there were some other stuff that were mostly homebrewed projects
which weren't, let's say, tethered to our applications for the measurements or that they
weren't sensitive to the electric fields that we wanted to measure so these two on the right-hand
side are both very cool projects and we used a lot of their, let's say, bases for our projects so
again cool ones but not the exact one that we wanted for the data in the research field so
a few words about the sensor we are calling it a mini-meal which is a miniaturized version of a
commercial field-meal electrometer that's what they are called and what it actually does in the
principle of operation is that you have a fan with two vanes that they're periodically screening
a sensing electrode on the bottom side of the fan and this what does is that it induces charges
on the effective area of the electrode and this time-resolved charge creates and induces
an un-stern induced current and that's what we measure with the sensor and the internal
processing and the data for the sensor are amplified and then we get the measured voltage
which is twice the amplified output voltage from each of the coupled electrodes for the
latest version of the sensor we were using DC-brustless motor which was used and the speed
controlled respectively in order to minimize the electromagnetic interference in our system
and the circuitry and then we also integrated gyro three-axis gyroscope for the rotational
position of the sensor so we were trying to use as low RPMs as possible for the optimal response
of the of the electrometer on the right hand side that's the exploded view of the sensor it was
used in we were using layers so we have like the cover plate which unfortunately you can see here
because it's shielded by the electrode view for the PDF and then we have the motor and the veins
that I told you about and then we have the motor mount and the back plate which was all
cut in aluminum for sturdy purposes and then we have the intermediate PCB with the electronics of
the sensor so it was ADC it was controlled by an analog to digital microcontroller and we used
a serial transmission for the data so it was all assembled in the institute with the two guys that
I showed you before and that's the final result for the sensor it's quite a small and robust sensor
like 8 centimeters at each side and we have used a thermal shielding because you know as you
go up within the atmosphere the temperature drastically falls and we needed to shield our
electronics and the battery supply and what it does is that I said measures the electric field
strength with the altitude so the pros for the sensor was that it was easy to reproduce it's a
fairly low cost sensor with all its the hardware and the electronic components components it's
lightweight and it's disposable which is it's a bit of a problem because you have you know all
these metallic parts and all these circuitry that are going into the ocean most of the times and
they are not retrievable because you know the cost of getting it it's quite larger than the
sensor itself so we will jump to another version which is going to be not biodegradable but
definitely with less metallic structures and hopefully it will be sturdy enough for the
measurements that we would like to do and same same validation methods so on the cons it was had
these bulky electronics because it was an implementation on a PhD level and we had the
minimal amount of knowledge for this for this project but hopefully it's going to get better
and better with SMD's and stuff so what it does in scientific terms it slightly overestimates the
electric field because as the sensor you know it's actually hanging from this balloon and you
have all these wings and shears that are hitting it as it goes up so we have parasitic electric
fields that can be detected from the motion of the sensor but we are using a rotation the rotation
of the sensor to minimize this effect and it has unfortunately a limited operation temperature at
minus 50 degrees it can mostly operate at this specific version on dry conditions so if you
have like heavy rain conditions it's going to be heavily biased in terms of the output but
that's that can be fixed easily and it has a maximum altitude of about 16 kilometers which was in
the atmosphere again which was fairly biased by the battery level freeze due to the decreasing
temperature so it's a sensor you have to do all sorts of calibrations to be ready and robust for
measurements that you're taking so we had a hard vibration test we were actually you know moving
the sensor around and getting the data we had the temperature resilience test and we tested
its response with a commercial which was well validated instrument and they had similar responses
pretty good ones and again we put it on different different conditions and the most you know famous
let's say set up for calibration of such sensors is that you're putting them like into parallel
plates and you're using a fixed voltage between the plates and you are securing the sensor in
order to measure this fixed voltage that you have and to control the output so that was the
standard calibration setup and it's also since it's pretty small and it doesn't have you know
these complex aerodynamics can be easily tethered to UAVs we haven't completely tested that through
modeling but we know that it's viable and it can send send its data so the telemetry now that was a
bit complex because we couldn't use we didn't have the knowledge actually to make a telemetry on
our own and just pop the data down but we also needed meteorological data from collocated with
our electric field data because that was just a single measurement and we need other parameters
also to explain you know this this ecosystem of models that we needed to use for the forecasting
so we created another second sensor which was also measuring its own stuff and we desechained our
electrometer to the second sensor and then to a commercial radius on if you are not familiar
with with these these are like small instrumentation that are flying almost every day from around
Europe and the meteorological services are releasing those those balloons and they are
giving us all the data that we need within the atmosphere for meteorological parameters so a
cool stuff that was done here the the radius hunt had its own protocol data protocol the X data
one and we needed to do a bit of reverse engineering in order to connect our sensor to the the X data
protocol and then trick the the ground station that was receiving the data that our sensor was
actually one of the commercial ones which was yeah which was dumb because you you just was putting
we're putting with our hands an ID and a fixed ID and the the ground station knew that that was
completely different sensor I said you know okay just passing through the data that's that's fine
and then we created the decoder for the for the data and then we have the raw output and also the
sensor was able to to measure as a standalone but on the ground not flying up in the atmosphere
with the serial that was giving out a text simple text output and then again we said you know okay
we have one we've made all this effort like for a couple of months to create one let's create
another 30 which was quite tedious but yeah but we needed that because you know when you when you
research all these dynamic systems as the atmosphere you need to have as temporarily dense data
so we needed to launch almost every day or maybe twice a day if we if we had the correct
conditions so of that we are going to a very very nice place the Cape Verde islands in South
Sahara and South Africa yeah and we've launched there through an initiative and a campaign that
we did with the ESA the European Space Agency it was called ASCOS it was a pretty big campaign and
it had all sorts of atmospheric stuff going on over there it was not only that part but we were
tasked to measure the electrical conditions in the atmosphere and some you know very fancy results
from the first experiments that we were doing on the plot whatever you see these colorful dots
these are different days that we were launching our sensors and on the x-axis you have the electric
field strength which is measured in volts per meter and on the altitude the x the y-axis you
have the altitude so within these layers that you can see but visualize here of dense dust particles
we have this increase of the electric field that we are seeing in different days of thank you
of launching our sensors and that was a pretty good win because you know from from this addition of
the sensor we were getting data which were quite realistic and we were getting some hints that the
dust particles were charged indeed as we were expecting again we did a correlation between the
wind speed and the electric field with a wavelet transform and we saw a small anti-correlation
but that gets a bit too researchy and technical so I'm going forward and that was a very very nice
day for us because we are going all the way again to Cape Verde and that's a day that we have a pretty
intense layer dust layer what you see with this colorful green thing over here is dust within the
atmosphere it's measured from a very specific laser which is called lighter and we also launched
the sensors that day in order to see if we have this electrification of the dust particles and it
was a pretty successful one we have many many and lots of data from the days that we have on the
campaign and and the data are also available so the sensors for the day let's say were operational
up to 40 kilometers due to battery decay so we are keeping the data up to that point
so now what do we do in terms of sharing all this work so primarily our repository is in github
and we have also collaborated with the evaluation and validation center for the data of ESA and
that's where the the raw data set from the sensors and the entire campaign can be found
we also have right over here the escos calendar which shows a step by step process of what were
the instruments used the the daily plots from the sensors and then all the other instruments that we
were having and all the work including all the publications done for the work the the data sets
and all the presentations can be found in in zanodo so please do contribute if you if you find it
interesting and yeah so some long bullets but i would like to to mention that so what were the
challenges that we faced as we were conducting all these open source practices and all these research
is that we had some you can have fairly large standardization issues so if you
have variations within the sensors and all the the bulk of the sensors there it can affect the
right reliability and the consistency of your collected data so another step was to have a
pretty good documentation quality so that we can ensure the the project success
and especially for those which that were not quite familiar with the hardware we do not have that many
contributions to know if it is a good documentation but you know please do check the the project so
also we needed to have a technical expertise minimum technical expertise for all those that
would like to assemble the the sensor or that we employ the people that we employ to assemble
the sensor so also we have data calibration and validation that needs to be compliant and with
the regulations unfortunately of large research organizations when you're talking when you're
talking about research that can affect many fields and being interdisciplinary so also we had to
battle a bit with the funding constraints which is present and limited in terms of the open source
and open research projects and we had to do a lot of testing and and also the quality control of
the data themselves can be quite challenging so also we have the the ending that's the long-term
support when addressing open source hardware issues through releasing updates of the of the
hardware and if that's going to be a compatible technology for the second version of the sensor
so the key takeaway is that do we answer our initial scientific question and fairly yes which
was quite good and the minimal produced nice results and we were pretty happy about that and
it's definitely not something that can be used only in research you can you can build it on your
own and just use it for fun if you'd like on your backyard so in retrospect in terms of the
in terms of the result that I had in my personal research is that the electrical properties
do not play a significant role on the long-range transport of the particles which was a boom
okay because we we didn't know all that work but again we had a milestone and a physical mechanism
that was not accounted before in all these research so what's next the next step is that
we want to migrate in complete open hardware technologies like a free cut and key card and
version the version 2 is being baked at the moment and we would like to do it on our local
hacker space with a bunch of people that were interested and yeah that's more or less it from
me thank you so much all and that's my email if you want to address some questions apart from the
ones that you're going to do now if you have to and my geek handle back there
yeah hi so if it doesn't turn out that electrical properties are not responsible for the transportation
of desert dust do you have any ideas or suggestions what might be yeah I do thank you for the question
that was that was one that I was expecting on my phd defense and never came so that's good yeah um
um a factor that I didn't you know quite oh do I need to you yes please repeat the question so
the question was that if there are the the electrical properties and not a factor that will
be very crucial for the particle dynamics if there's something else that plays a role and if
we have an idea about that and yeah yeah we do um it's actually the orientation of the particles
which was the the second part of my phd that I was uh researching with an instrument and we've seen
that particles are indeed getting oriented in the atmosphere and from you know complex modeling of
the particle dynamics we know that they're going to float a bit more from that movement alone so
but that movement won't be efficient only by the electrical forces you have winds
like strong updrafts that um are gonna you know orient the particles or maybe do a sling sort of
effect and make them flow within the atmosphere so there are pretty complex mechanisms but that was
a bit a small milestone to that maybe one more yeah yeah really one of the open source hardware
uh so in your documentation do you also essentially for example
duck on all the steps of the hardware along with for example calibration and maybe maintenance
and repair details yes you said you're working on a second version are there any efforts for example
to say institute replication efforts around the if there is a story and a replication to essentially
as a open source hardware application yeah yeah yeah it's going to be so we have recently uh well oh
yeah they repeat the question yeah I have to remember all that you know and my my brain is jammed so um
if the the the question was if the current documentation uh has you know all the the
tedious processes that we've used from the hardware uh documentation to the um steps step by step
process of calibrating the sensor and stuff so yeah that's that's correct we have it and uh the the
concept is to have to be able to you know with with some small steps to be able to recreate the
sensor yourself um it needs a bit of you know cnc machining and cating it doesn't have 3d printing
at the moment but maybe uh the best strategy would be to wait for version two which is going to be a
fairly usable and much more usable and then you can reproduce the results yourself so the the basic
calibration process was the one that I showed you we did it like in our in our house and it's yeah
you you need the voltage supply and the the plates and that's more or less it but yeah for for the
purposes of the research you need to do all the other stuff that I numbered in terms of calibration
thank you yeah uh is this kind of measurement also done in space
yeah that's a nice question um the specific yeah is it nice you know you you want to go with the
flow and just answer quickly but that's yeah so are that no no I didn't say it did I say sorry
um so does do such kind of measurements get repeated uh in space uh well not with the specific
sensor because it's um pretty um pretty bad in in low temperatures pretty pretty bad in low
temperatures and it doesn't have space hardened components so the the basic strategy to go to
there are like rods that are collecting particles and these are translated to electric field
measurements when we talk about let's say rovers for example when you're going to mars which is
actually the image that I showed here so that's the planet marsh and it has a fairly large global
dust storm um which is pretty pretty nasty and lasted for at least a couple of years so when
when you're speaking for that kind of technology that's the go-to sensors but these were sparse
I think there was actually one mission that was successful and that landed on on mars with such
an instrument that was using electric field measurements and then apart from that nothing
yeah around the earth around the earth yeah um not not that I'm aware of I know that there are some
uh processes of magnetic field measurements that are done with small uh pocket tube satellites
but I'm not aware of electric field measurements yeah because you know if you make the satellite
two centimeters bigger you have the nano satellite format and you can it's quite easy to get in
yeah yeah it's quite easy yeah and I hope that you stay there all the time yeah all the time
I know um we're actually uh I'm pretty close with guys that are uh with us uh in in the room
they're called uh Libre Space Foundation and they are using all sorts of open hardware and
open software stuff to make small satellites so it would be a nice collaboration let's say where
yeah he's waving yeah he's doing all sorts of mechanical engineering stuff yeah so
it needs the the objective it needs the scientific objective yeah that's it okay
thank you so much thank you