Tutorial 09 for Arduino: Wireless Communication Video Lecture | Arduino Programming: Step by Step (to become an Expert) - Electronics and Communication Engineering (ECE)

hey everyone Jeremy Blum here with my
ninth Arduino tutorial sponsored by
element14 this week's going to be all
about wireless communications we'll be
using to arduino who knows to xb radios
and to xbradio shields to have the two
Arduinos communicate with each other
I'll walk you the process of programming
the XP radios getting them on the right
channel to talk to each other and then
we'll end up with a project where we
hook up with a potentiometer to one
Arduino and have a turn a motor
connected to another Arduino all
wirelessly so let's take a look at those
parts for today and get started here's
what we'll be working with today here I
have two arduino who knows 2 XP shields
for the arduino and 2 XP transceivers
the transceivers don't have to be
exactly the same model you can see that
they're a little bit different here
that's just fine I also have this
sparkfun USB 2 XV adapter this will
allow us to program the XPS through
serial interface in the computer very
easily you don't have to use this though
if you don't have one of these although
I recommend that you get one you can
also plug the XP into the XP shield and
mount the shield onto the Arduino Uno
and then program it through the Arduino
Munoz programming interface however to
get that to work and make sure you're
not actually programming the Arduino and
that you're programming the XP you'll
have to move these two jumpers on the XP
shield from the right to left position
and you'll have to physically remove the
atmega microcontroller from the Arduino
Uno this is to ensure that all the
serial communication goes between the
computer's USB port and the xbradio
that's why I recommend using this it
makes the whole process quite a bit
easier I'm going to use this special
breakout board from Sparkfun comm to
program our XPS each xB has to have a
sign to it a unique ID information about
the other xB that it will be talking to
and a special pan ID hand stands for
personal area network all the XPS that
are communicating with each other have
to be on the same personal area network
so we have to program those three
numbers into the xB so that we can get
it working with our Arduino start by
putting the xB onto the Sparkfun shield
make sure you put it on in the right
direction otherwise you could damage it
there's an outline on the shield that
shows you the direction which it goes in
then plug it into your computer via a
mini B USB cable
it should light up now let's go to the
computer and get it programmed you'll
need a terminal program if you're going
to connect to the XBee module and set it
up I like to use putty on windows 7 but
if you're using Windows XP you can use
hyper terminal and if you're using Mac
or Linux you can just Google for a
terminal program and basically use
anything but if you want to use putty
just type in putty on Google and go to
the download page and you can just
download the putty that exe here the
next thing you're going to need to do is
figure out what comport if you're on
Windows your XP wireless module is
connected to same thing goes for Linux
or Mac but it won't be called a comp or
it'll be called some other thing that
you'll need to enter into your serial
program so you can identify where you're
communicating with do that in Windows
you go to my computer click on
properties go to device manager and if
you go down to comm ports you can see
that we're using USB serial port 4 it'll
be called USB serial port so we're on
comm 4 and we need to know that for
using putty so let's launch putty and
we'll choose serial put income 4 and go
to terminal
and make sure you force on local echoes
then go back to session and hit open ok
we're now connected to our XP wireless
module now we're going to program the
XBee module first you enter programming
mode by typing 3 plus signs in
succession then I'll go through and type
in three commands it set the ID of the
module the idea of the module it's going
to communicate with and the personal
area network ID so that we can set them
all up follow along with me as I do this
you have to go faster at times out in
the event that yours times out and you
don't get in ok after entering something
just enter the three plus signs and
start again let's get started type in
plus plus plus wait for the ok then type
in 80 my 1000 that sets the ID to 1000
you should get in ok at the beginning
then type a TDL 1001 it enter you'll get
another ok that's been written the last
thing we're going to do is set the pain
ID
type in atid 1 1 1 1 then a comma
you'll get ok at the end then type in WR
and hit enter that will turn into an ok
the WR writes the values to it
permanently so that even after it loses
power it still has those data that data
stored inside of it ok perfect now
unplug that one plug in the next one and
we'll program that as well ok I've been
sure to unplug the USB first to remove
power and then I change the xB modules
putty will now say that it's inactive
because it lost connection over USB will
restart the session by right-clicking in
title bar and hitting restart session
this will reconnect it and bring us to a
new line we're now ready to start
programming a second module well follows
very similar steps again hit 3 plus
signs to enter programming mode wait for
an ok then type in atmy 1001 this one
will have ID of a thousand in one hit
enter and you should get another ok then
type in 80 DL 1000 this is the idea of
the one we just programmed hit enter and
you get another ok lastly we'll set it
the same pan ID ati d 1 1 1 1 comma
you'll get in ok and then type in WR and
hit enter and it's written ok both of
our x bees are set up to communicate
with each other now we can close this
window and start playing with them now
we need to write a program for each
Arduino will have the first Arduino read
in information from a potentiometer and
send it over serial net serial will
actually be transmitted into the
wireless signal that's created by the
XPS the X B on the other Arduino will
receive it and then use it to turn a
servo motor let's write the programs for
each of these first I'm starting off
with the program that we wrote in
tutorial number 6 that write in the
information from attention ometer and
put it over serial this is already most
of the way there I'm only going to
change one thing here instead of
transmitting a data from value from 0 to
255 I'm going to transmit a data value
from 0 to 9 this will just make our
lives a little bit easier as it means we
only have to transmit one one byte of
data and we won't have to worry about
too much processing on the other end
this will allow us to turn the motor to
nine independent positions which can be
very useful for controlling things like
a robotic arm for example so save that
one and now let's go open it up another
program that will you
to control the motor now I have opened
the servo control program that we wrote
in tutorial number five we're just going
to make a few modifications of this so
that it turns based on serial input
instead of in part from an infrared
sensor which is what we had originally
written it for remember you can download
this from my website so first off we
don't need the distance pin anymore
because there's no more infrared the
rest of this still looks good in the
setup we're obviously going to have to
add a serial initialization because
we're going to be reading in serial data
remember the XPS are actually
communicating basically over serial data
except it's happening wirelessly so
we're going to read in serial data
that's going to come over the xB modules
okay good now down here we can get rid
of our distance sensor and let's read in
our serial value so the first thing
we're going to do like we've done before
with serial is we're going to wait until
we actually have a value serial dot
available and we're going to set that
equal to zero okay so this is an
infinite loop and it's just going to
stay here until it has something
available on the serial line coming in
to it from the other xB now let's read
in the data so we'll use the same trick
we did before and this is why I decide
just make it zero to nine it'll make our
lives a little bit easier we'll do int
data equals serial dot read minus the
char zero and if you remember from
before this is converting the byte or
char value that comes in into an integer
because this is a this is the decimal
representation of the number zero and it
will convert it into an integer for us
which is exactly what we want so now
we'll have an integer data that ranges
from zero to nine based on a value that
we just got okay now we're going to
write a new variable called position
that map's that to a value from 0 to 180
because the servo turns from 0 to 180 so
we're going to map data from 0 to 9
to 0 to 180 like that and just to be
safe I always put a constraint function
after my map functions just in case you
get some erroneous data coming in for
whatever reason so to position 0 180
let's just make sure that no matter what
our values are always between 0 and 180
otherwise the server will freak out and
do weird stuff ok now we actually want
to turn the servo so let's get rid of
this we had the function for turning the
servo right here if you want you can put
in a line here to print to the screen
and see the values coming over but
that's not necessary
what is very important though is putting
in a serial ushe and what this will make
sure happens is that any extra data that
came in between when it read this
because it remember it's only going to
read one character with serial deck read
it's just going to read one character so
if 18 characters came in over this time
period
we only want to read the one that we
care about and then flush the rest of
the buffer up otherwise this server is
going to be flying all over the place
and it's not going to know what to do
with itself so this is very important
and that should do it so save this and
now download each of these to your
Arduino Arduino --zz before you attach
this XP shields I now have both Arduino
is plugged into the computer with no
shield attached via USB however I have
no idea which one is on which comport if
I go if I have both of the programs open
I can go to tools serial port and see if
there's something on comm 3 and selling
on comm 5 so I'll hook this one up to
comm 3 and this one up to comm 5 make
sure they're the two different comport
and I'll program the pot or the window
first so this is the one that's going to
accept the input from the potentiometer
and while I'm doing that I look to see
which LED blinks so I know which one to
hook up to the potentiometer so let's
hit upload ok and you can see the LEDs
on this guy blinked so this guy is our
potentiometer board now I'll upload the
other sketch to comm 5 and we can see
that the LEDs are blinking there ok
perfect so this is the one that we're
going to hook up to our motor let's get
those wired up first
ok I finished wiring everything up now
when I plug the USB back in
both always make sure you unplug the USB
when you're setting these up on the
potentiometer side I have an XP shield
mounted on top of the Arduino Uno with
the xB that we programmed for the pot in
that socket the pot is hooked up with
ground to ground as you would expect
Green goes to the analog input zero
which actually goes up through the pin
into the xB shield and can be plugged in
right above where ordinarily gets
plugged in all these pins here are
broken out so that you can continue to
use them the 5 volt one however
gets covered up by the XBee module
that's no problem just plug in a Y
underneath it with this green one right
here and then run that and then when
that went to the pot on the motor side
we do a similar kind of thing where you
want a wire underneath it before you put
the shield on so that you can get it
into place it kind of gets squished down
by the shield that's fine that 5 volts
goes to the motor ground gets connected
to ground on the Arduino over on this
side and then this one gets connected to
pin 9 which we do PWM servo output on to
control the servo when you're all done
with that plug the 2 USB ports back in
as I did now let's see if this actually
works if we grab the pot here and give
it a twist perfect the servo turns
exactly nine different clicks which is
precisely what we wanted you can use
this for a lot of things you can use it
to make a claw all kinds of stuff
although you'd obviously have to send it
more resolution but I can turn it and
the servo turns just as we would expect
it to now keep in mind the only thing
USB is doing here is providing power
there's no communication happening
between these other than the
communication between this X B and this
X B you can just as easily plug one of
these into a 9 volt battery and power it
like that
I just want to make one more quick note
on programming the Arduino when you have
an XP shield attached remember before I
did it before I attached the shield
there's a good reason for that
xB hijacks the transmission and received
lines that the Arduino uses for
programming so they can use it to
transmit data that's fine but if you
want to program the Arduino and while
the XP shield is plugged in you'll have
to reset both these jumpers in other
words take the jumper off of the pins
and move it to the two outermost pins on
both jumpers that will allow you to
program it via USB but then once you
have the program on
forget to switch the jumpers backs that
wireless communication works as it
should
thanks for watching this episode of my
Automator tutorial series I hope you
guys enjoyed it as always if you have
any questions or something's not working
right feel free to post a comment on
YouTube on element14 or my blog and I'll
have the source code available online as
well if you're having trouble with the
XPS you're not alone it can be very
difficult and frustrating to get them to
work sometimes I the first course of
action I'd suggest you take is to Google
the problem chances are someone says the
exact same thing happened to them that's
usually what I do and I'm having
problems with them otherwise get in
touch with me and I can try to help you
out with it alright until next time
thanks for watching thanks to element14
for helping me to sponsor this video
series they were kind enough to provide
a lot of the materials that I'll be
using to create these tutorials
feel free to go visit their website at
element14.com check out their community
which is a great place to talk to you
about electronics the arduino and
basically anything else engineering
related and that's all of a store where
you can buy a lot of the parts that
we'll be using in these videos
you