LESSON 23: Arduino GPS with Data Logger

This tutorial presents step-by-step instructions on using the Adafruit Ultimate GPS unit and the Virutabotix SC card reader and an Arduino to create a data logging GPS. This builds on the work presented in LESSON 22, so go back and review that one first. You can see complete details by going to LESSON 23 at http://www.toptechboy.com

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Closed Caption:

hello guys I am palma corner and i am
here today with lesson number 23 on
using the Arduino microcontroller we
have an exciting project today it is an
extension of lesson 22 what we're going
to do today is we are going to create a
GPS data tracker and the way this works
is is that you've got a gps we are using
the most excellent at a fruit ultimate
gps connected to the Arduino and we are
using the virtual bow tix SD card reader
writer and then we're going to power the
whole thing with a dandy rechargeable
battery and so when we get this thing
programmed up to plug the battery and
walk around outside and it will
constantly be logging our position our
GPS coordinates and then we come back
inside we can take the SD card out pop
it into the computer and we can see
where we have been using google earth
and so this is a pretty pretty exciting
project and we're going to jump right
into it and get started the first thing
that you're going to need to get started
I go ahead and the easiest way to get
this information is to go to top tech
boy calm my website and when you go to
that website you can look for arduino
lesson number 23
ok arduino lesson number 23 and what you
will need to do will need to connect up
the gps I let's see let's talk about
where you can get this stuff I've got
links here of where you can get your
arduino the ultimate gps virtual boat x
SD card reader the battery clip and the
9-volt battery system or you can hunt
around and see see where you can find
this stuff but these are the these are
the specific units that i'm using ok
you're going to need to hook your gps up
for easy connections to get the gps
hooked up to the Arduino Uno the end of
5 volts ground-to-ground rx2 pen too
RX depend too and txt pen three
you'll also need to hook up your virtual
bow tix data logger and you can use that
I as follows ground ground ground from
the SD card to ground 3.3 volts is not
used because we're going to connect with
5 volts 50 volts 25 volts the cs chip
select on the eye on the SD card to pin
for most see on the sdcard depend 11s
ck2 1013 me so depends 12 on the Arduino
and ground-to-ground so there's a ground
on both sides of this just to be safe I
hope both of them up to the Arduino
because you're powering a lot of stuff
here you probably need to create you a 5
volt rail here in a ground rail and then
just hook your 5 volts into here and
hook your father built into here and
ground and so that you have plenty of
connections foreground and 5 volts
because our circuit is starting to get
pretty pretty complicated okay we need
we need to go ahead and get the hood
that we developed in less than 22 and if
you haven't gone through lesson 22 you
need to do that you can go to top tech
boy . com go to Arduino lessons come
down and you should see lesson number 22
and if you go to less than number 22 you
can catch right up to where we are out
were here is the code you can click this
we can copy this code you need to go and
develop this yourself but I'm assuming
you've already done that on less than 22
so you can just jump right in what you
had before and then we start with a nice
new arduino development environment and
we come in and we placed our code from
less than 22 if you remember what we
ended up with on less than 22 we just
kind of got to the point that we could I
talk to the gps and then we were just
sitting there and we were printing out
our gps we were about printing out our
nema sentences
ok and so just very simple we were just
printing out our nema sentences and we
could see that we were we were getting
those numerous sentences off of the gps
and then we were we were printing them
out yesterday or listen 22 we didn't
actually take the thing outside and walk
around with it because if we did that
there would be no way to see what the
data looks like so that's what we're
going to do to date today we can do that
because we'll have the data logger and
we'll have the battery where we can
actually walk around outside but there
is a little code that we need to develop
before we can on before we can do that
and mainly what we're going to be doing
today is we're going to be taking the
code from less than 22 and we're gonna
be getting that on that SD card working
i think it was in less than twenty one
that we learned how to do the SD card
reader and so hopefully already have
your card reader and hopefully you can
recognize this stuff and in fact figure
out most of it for yourself since we've
already kind of odd kind of done most of
this in on in in earlier lessons okay so
let's just jump in here and start doing
our code if we are going to use the SD
card reader we've got a load the SD
library
the good news is the SD card library is
already it's something that comes with
arduino so you don't have to install it
you just gotta load it into this sketch
so we go load SD HR include sdh and on
that is simple and up load SD card
library right
we also the SD card needs to use the
spie the serial peripheral interface
library and it's just a way for
sophisticated components to communicate
to each other and so we're talking
between the SD card and the arduino
using spi which is a very useful
protocol h remember in this unique case
of loading our libraries we don't put
the semicolon payload the SPR I library
right remember that you've got install
this adafruit library and you can go
back to the earlier i think the previous
lesson 22 to see how to install this
library so you can just load this one
because it doesn't come with
the arduino you have to actually install
that library lesson 22 will show you how
to do that
ok we come down here the rest of this
looks pretty good
what we are going to need to do is to
find a few variables for using the SD
card reader if you remember we have to
tell it where r chip select is connected
and we cook connected the chip select
pin for time ship see like this part you
know and for ok and we have to have a
file object because we have to treat
this SD card reader as an object so we
have to have a file variable and
remember we've done its we've done
strings we've done floats and now we
have a variable type of file which is
very good for interacting with files and
we're going to call it my sensor data
ok the filename that we're going to use
this my sensor data
ok be clear variable for AA reading for
your sdcard object
ok so that's just a convenient way that
will be able to write to that file and
read from that pile by having an object
name that's a top file
ok so that's pretty good now we come
down here and we are setting up our gps
and we also need to while we're in the
void setup we need to set up our SD card
and if you remember there are some
quirky things about this card that it
wants to have 10 10 reserved as an
output and not use for anything else
even if we're not connecting to it must
be clear and I'm count put this card
reader happy
okay sometimes you just go with it
whether it makes sense or not
now we need to turn it on so it's called
SD because that's not what the library
is we do an SD begin
ok and we want to do an SD begin and we
gotta tell it where we're connected what
where we connected we are connected to
chip select ok so we've got to tell it
chips and chip select it's for I guess
we could write for in here because we
got the chip select connected 24 but
it's just better practice to use our
variables
ok so we initialize our SD card and say
it is ships all right that looks good
let's see on there's a there's a couple
of things that we're going to have to
jump right into here I what we want to
do is remember that we're creating a
file and we're writing the final here
and when we open a file on that SD card
if we open a file if the file doesn't
exist it will create it but if it does
exist then it depends data to it and the
problem with that is that you end up
with all the old data from your earlier
experiments for your own earlier
walking's around and so I want to just
take a second here and if the foul is
there on the SD card I want to erase it
okay if the file is there I want to
erase it so that then i start with a
clean fresh file and i get rid of that
old data
okay now this is a couple of new
commands that we're going to learn is we
can see if a file is there we can do
that by saying if SD SD . consists okay
and we'll put follower we looking for
we're going to hold our data in m.e a
dot txt right and actually we're going
to have to data files and I always like
just always like to store my raw nema
sentences because of anything goofy ever
happens you can go back and look at
those nema sentences and you can see
your raw data so i always like to have
one file where I'm just dumping those
nema sentences to and so I'm checking to
see if that
nema dot txt file is there and if it is
there
ok we're going to check and see if nema
not text is on the card gift so delete
it so this is the starter might've
statement let me in my is statements i
don't forget to do that so open curly
bracket to start the if statement close
curly bracket to end it and then what I
want to do inside that well if it's
there i want to SD . remove it and make
sure I get it in here right
i'm going to copy that copy and then i'm
going to paste it like that so if it's
there
remove it ok so that will get rid of the
old file now I said I had to file so i
want to do this for the second trial as
well so i'm going to come down here and
just copy and paste so i take those
three lines and I copy and paste i'm
going to do this for my second file in
my second foul
I'm gonna have his GP s day talk . txt
gps data dot txt and i will copy and
paste that alright and what I do is in
this nema file
oh we're going to select save the wrong
nema sentences and in this file we're
going to save rgr parse GPS coordinates
and elevation so we'll have two
different files so i want to check and
get rid of both of them before I move on
that looks pretty good so we got our odd
we've got our I things going there now
we come down to our main loop and we're
going to read the gps and remember this
read gps is a function that we created
and what it does is it goes in and it
clears the gps and then it reads into
good sentences and when it gets too good
sentences it pops back up here so when
we get to this line in the code we
should have two good gps sentences and
they should be parsed because we parse
them as well right.we said gps I gps
parts and so that once we parse them
down here then that opens up some new
commands that we can do up here but one
of the things is that we don't want to
do anything if we don't have a fixed
shit and a fixed just means that the gps
sees the satellites the gps sees the
satellites and it's getting good data
ok and it will spit out empty nema
sentences but we don't want to save any
of that data until we get good . good
I gps state or get a fix and so what we
doing here is we're going to look and
we're going to say this gps . 6 equals
equals 1
so what happens is gps . fix is going to
be zero until we get a fix and once it
gets to fix than gps . fix is equal to 1
and so we're checking if gps . fix is
equal to one then we're going to look
we're going to go and we're going to do
all these following commands and so when
you go ahead and start my statement and
really everything is going to be inside
here because we don't want to save any
of the data or do anything unless we
have a fix and so what this is going to
do is like right now if you look at this
red light blinking kind of on and off
that does not have a fixed and I don't
have a fixed because i'm inside and you
can't see the satellites through the
roof but when you have a fix this thing
will just blink like once every 15
seconds when you walk outside watch that
red line and when it just blinks once
every 15 seconds that tells you you have
your fix
and then once it has the fix then you
want to log the data
okay so only clogged data after you have
a fix right so when I am here now i am
going to put a little white space in
here while I'm here I'm gonna have a fit
fix and so what do I want to do if I
have a fix what i want to write the data
to the SD card so i'm going to open my
first file and
we call this file that we're working
with up here the file type is going to
be my sensor data so i'm going to say my
sex or wat is going to be equal to what
we need to do we need to open the file
OST got open and then we gotta tell it
put the file name is in me2 . txtm8 and
remember that's the file that we erased
up here so we're going to be starting
with a clean file now when you do an SD
open and there is not that filing their
it'll create it so even though you've
erased it it'll create it here the end
of the first time through and then how
do we want to open it
we want to write we're going to have a
file right and so that just tells it
that when you open it you want to open
it for writing so we're going to open me
my txt for writing
alright so now that we have opened it
what we want to do we want to write
those two sentences remember in the
earlier lesson when we do this GPS read
we get to gps sentences in MEA 1 and em
in da to one of those should be your rmc
sentence and the other ones should be
your GGA Senate so we should have those
two sentences and we want to write them
to the data spouse i'm going to say my
dance floor data
okay . Brett help because I just want
one sentence per line and then we'll
print in ea1 first sentence right first
kb stay hard
ok and then i'll just copy and paste
this to make it easier ctrl-c ctrl-v and
then i'll write my second nmea my second
name of sense to the on SD card
ok I've written those things I got to
always remember to close my file so i'm
going to close this file object out on
CL OS e like that
okay close the file
alright so that little bit of data right
there is gonna is going to write I was
going to write the data to the odd to
the going to write the to nema senses to
the SD card but in addition to that what
I'm going to want to do is in addition
to that I also want to put the parsed
data to a different file and remember
when we came down here and in our avoid
gps read when we do a GPS read we
actually come down and we parse the data
we do a gps . parse of the gps last nema
and what that does is that opens up all
these new commands in that library where
I can just go out and I can grab things
like grab the latitude grab the
longitude grab the altitude okay i can
just go grab those things and so that's
very useful so since I parsed it down
here in the eye since I part sit down
here in the void read GPS function i can
come up here and i can just start
writing new stuff to that other file but
if i'm going to write new stuff to that
other file the first thing I need to do
is open it so i need to do I sense i
sense or data . my sensor data i is
equal to make sure i spelled it right my
sensor data is equal to i got to open
the file again SD . open but I don't
want to
put it in this nema txt file i want to
put it in a new file and what I'm going
to call that new file is GPS d'etat txt
like that and how do i open it i'm
alright so we'll say file underscore
right because i want to open it for
writing okay and so what this is gonna
do is I open e gps data txt on cuts st
park
okay i think that would be good now that
it's open i can write it so i'm going to
cite my since work data . fret and then
I put in here what I want to print to it
ok and what that the command i want this
is what I want to print I want to create
print the latitude and then the comma
and then the longitude
ok I get the latitude by getting gps .
latitude I get the longitude by GPS .
longitude and then also one of the
quirky things is that it's not just the
latitude the number you also need to
know which hemisphere you're in north or
south on latitude and east or west on on
longitude and so we need to we need to
print those things out as well and so
let's just start first thing that we
want is to print the key he s . black
kid too
ok and what we got to be sure is that
normally when you do a print I think it
gives you two decimal places
well that latitude number is going to
have four decimal places so i had to put
the comma 4 there just to make sure that
when it puts us on the SD card i get all
the data that it doesn't truncate it
because on the GPS locations we want it
to the very last time very last decimal
point so we're going to write write a
lab to to the US
yeah that you to the GPS file all right
now my sense or later . print we gotta
tell it which hemisphere it since we do
gps . and to get the provide the whether
you're in the end or the eye on
ah latitude yachts in RS you just do l8e
and that'll give me either in or an s ok
which I this fear you are and which will
be in or an s now we want to be my since
four and notice how I'm putting this all
on one line because i'm doing prints
because I want this one I want latitude
longitude and altitude all on the same 1
theta dot print and i'm going to do
cheap gps . long 112 okay and I want
those four decimal points on that as
well
ok so right launches 22 pts I'll my
sense for data . still on the same line
print gps . hello in and what that's
going to be as that will either be at e
or w ok for east or west and you need
this information because we would go to
put this stuff into google maps it wants
to see where you are north or south east
or west so ah which and this year you
are in this is east or west like that
ok I i think i forgot to do something
here I forgot my comma so after i did
latitude and lat I need a comma in their
kind after
after that I need to do just a my since
my six or data . and i need to print the
comma comma like that Mama and I've got
longitude and lon
ok now i need another comma my sense or
data . print and now what I'm going to
need is I ji ki us doc altitude okay and
that will just pop that altitude right
in there like altitude
ok now I've written all the things i
need to write what do i need to do hope
you remember to close the foul
believe me you have more problems
because you don't close your files that
we speaking of the students that I have
oftentimes forget to close their files
you sure you're alright
ok so let's look at this I come up I
read the gps if I have a fix
then I want to write all of this data i
open my nema file i write my to nema
sentences and I close my nema file i
open my gps data file i write my
latitude than the which hemisphere i'm
in i write the comma i write the
longitude i write the lawn which
hemisphere on in and all I need a comma
in there between those two so I want a
comma between my longitude the altitude
so I forgot to print
crunch and I need a comma and also when
i get to this this is the last thing on
that line and so we're going to a new
line so i need to put the println there
ok so let's see if this thing is going
to work your let's see if I made any
mistakes let's go
no I didn't mean to do that what's not
to like that
Oh what does it not like ah up here on
this African forgot my colon semicolon
there did you guys catch that hopefully
you did as I was going through it
hopefully were yelling at the top of
your lungs get me to put my semicolon
there
ok so now it looks like it's going to
compile it looks like it's going to
download and let's hold our breath i
hope i don't have a serial monitor /
yeah I took it
ok so now if I look at the serial
monitor i think i should see let's see
oh yeah I have the print statement down
in the this isn't those rights we just
did but remember in that GPS read i had
a print statement and so we see an AMC
and annecy and anna c and a messy and
Tennessee and we're sitting here we are
sitting here reading ah these new
sentences and we are getting a good day
and a good see all these look like good
sentences and so this all just looks
really good so i'm going to go ahead and
close that so now guys what's going to
happen
I'm gonna go outside and i'm going to
walk around so i'm going to unplug this
from the AA from the computer
alright the programs already down in it
so now i'm going to take my little
9-volt battery and i will get this where
you can see it and then you see this
right here that is for plugging in the
9-volt battery and then when i plug it
in which you can see is the arduino has
come back to life and the gps has come
back to life and I am completely mobile
I am free to roam around the area so
what I'm going to do
someone I run outside i will pause the
video run outside and then continue the
video and then what we'll we'll look at
this data coming out of here right now I
don't have a fix right because that led
is blinking fast i don't have a fix the
red LED is blinking I don't have a fixed
so there's no data being logged right
now but as soon as I go outside it'll
take about 30 seconds to get the fix and
then I'll walk around then we'll come
back in and see if we can see that data
ok out
ok ok I'm back and I have been outside
walking around brought the unit back in
you can see that we were operating on
battery power alone and what I've done
is I pop the SD card out i can stick it
over in the computer and let's open that
SD card up and see what we can see in
there give me just a second here so I
can pop it open and what we can see is
that there's two files and it's the two
files we created in it in e a dot txt
and GPS data . text this one should just
have the nema sentences
let's take a look at it we pop it open
and sure enough this is the MC the rmc
sentence in the GA sentence rmc GA it so
we're sitting there and we're grabbing
one of each type of sense and we're
dumping it here to the SD card and if
you can remember in our previous lesson
are numerous sentences were empty they
had a bunch of commas and zeros and you
can see here when we went outside and
actually gotta fix we're now getting
data this represents the time
30 51.7 880 north is our latitude and
then our longitude and it shows that
were in the northern hemisphere the
Western Hemisphere and so there's all
types of useful data in here but this
date is kinda hard-to-read we just like
to keep kind of the raw data the better
data should be in our gps data dot txt
file and we open that i'll look at that
we have latitude and then northern
hemisphere comma lon longitude and we're
in the Western Hemisphere and look at
that our altitude $OPERAND meters and so
let's check that altitude and see how
that looks it says that i'm at 779
meters and so what i can do is i can
come over here and i can say 779 meters
in feet and that's saying that I am at
an altitude of 25 5577 which is very
close to what I known altitude is at
this location so this is really neat i
went outside and walked around
little bit and i got these sets of
coordinates but how could we use these
coordinates in google earth so let's
open up our google earth be takes a
second to get open and close that and
then get this the nice size where you
can see it
ah ok so let's call back this and of
course right now we don't want to be
putting altitude in there
we're not quite ready to do that yet but
let's just get these two
ok so i'm getting the latitude and
longitude I could come up here to Google
Earth and paste it in and I say search
and it says I don't understand this
ok and I'll explain to you why you don't
understand it that the way this this
comes out of the nema sentence is the 30
represents degrees and then the 51.7 93
is minutes so it's 30 degrees 51 minutes
7950 1.79 37 minutes in the northern
hemisphere this would be a hundred
degrees and 36 minutes
so when you find the decimal point and
to the left of the decimal point is
$OPERAND minutes so that's 36 . 027
three minutes and a hundred degrees and
google doesn't understand this nice long
thing you're it wants to see a space and
so that looks to google like 30 degrees
51.7 9 37 minutes it's morally here the
two by the decimal point of the minutes
so I come over here and this is a
hundred degrees so it's always two to
the left of the decimal to the left of
the decimal and then i had a hundred to
the left of the decimal and then I had
30 and now let's put search and look at
it looks like it's coming to Texas it
looks like it's coming to my location
here in a resume and this is exactly
where I went
to walk around now let's see exactly
where am I here i am right here
I mean this is actually right at em I'm
in this building the school and I came
out and I came over here to stand in the
shade and I rest in the shade for about
45 seconds call it was getting a fix and
then I started walking around and so
let's see if we can see me walking
around a cop
I don't want the altitude so i'll just
copy this and then i'll come in and
paste it and remember to the left of the
decimal groups so that's 30 degrees 51
to the left of the decimal hundred ok
and you can see I got here and I started
walking around the courtyard a little
bit let's come down and get one of the
get one of the later ones and what it
should be especially just be kind of
continuing to walk around in the
courtyard so copy ok and then you can
see what i did was i walk from there
back to the back door and then I went
back in and then once i went back in it
lost the fixed because the ceiling the
gps can see it so this is just really
need we now have a device that we can
walk around with and it will log our
position as long as this little GPS has
a clear view of the sky and I think this
is just really really slick we can come
back and then we can plug those
coordinates into google and we can see
we've got google earth and we can see
where we were this is just really really
really neat i'll tell you what I hope is
I hope you will come back for the next
lesson which what I think the next
lesson is going to be like less than 24
hour race let's see this has been ahh we
are presently on lesson 23 and so if you
come back for less than twenty-four what
I'm going to do is I'm going to show you
that you know kind of like that the
little bit slow thing about this was we
have this this this data file that has
all of these coordinates in it
what I'd like to do this I'd like to
take that data file and show you how you
can generate a track where you can just
go to Google Earth and you can import
that and then you can see your whole
either you're basically your whole track
and so that's what we're going to do
next week thanks a lot for tuning in and
we will see you guys shortly