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Electrical engineering
Course: Electrical engineering > Unit 7
Lesson 5: Bit-zee Bot- Bit-zeeeeeeeeeee
- Bit-zeeeeeeeeeee (long version)
- Parts for Bit-zee and It-zee
- Tools for Bit-zee and It-zee
- Introduction
- Planning and propulsion
- Parts
- Chassis/frame
- Wheel mounts and fenders
- Component mounting holes
- Batteries/power
- Battery wires
- Power wires and on/off switch
- Motors/propulsion
- Motor controller functions
- Motor controller
- Motor controller connections
- Arduino connections
- Digital camera connections
- Digital camera connections II
- 5 volt power distribution board
- Digital recorder/player connections
- Power connector for the Arduino
- Prototype board
- Motor controller connection to Arduino
- Camera connection to the Arduino
- Bumper switches
- LED eyes
- IR sensor
- Chassis modifications
- Camera wiring update
- Programming
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Planning and propulsion
The video covers the first stages of idea generation for Bit-zee and how to make Bit-zee move. Created by Karl Wendt.
Want to join the conversation?
- Has anyone tried to build bit-zee yet, or even a robot?(19 votes)
- Yes, some have, but, as far as I know, they say its long, time taking. I found it tricky. But, give it a go if you can.(15 votes)
- Is there a kit you can buy or information on where you get everything(7 votes)
- I wish you could, but than you wouldn't need these videos. there would be instructions.(1 vote)
- what exact arduino do i need?(6 votes)
- For this specific robot, you will need an Arduino Uno. These can be bought for twenty to thirty US dollars.(1 vote)
- I have this same Arduino as in the video, and it came with a 9-volt battery and adapter, but at, the video states that the Arduino takes 5 volts. 4 volts is a big difference, so why can the Arduino run on 9 volts and not explode or do something else bad? 2:49(3 votes)
- I think he means it needs a minimum of 5 volts. However, I would send 200 volts through it, it might really explode!(2 votes)
- What if you do not have any of the things?(2 votes)
- Obviously you buy them, several other answers have lists.(3 votes)
- Instead of the hair dryer motor could you use a regular 12 Volt DC motor?(2 votes)
- Is there any way to use 3 motors, keep the wheels spinning in 1 direction, and use a motor to turn the robot?(1 vote)
- Very thoughtful! Indeed, there are many different types of "drive bases/systems". In fact, there are some wheels which can roll both horizontally and vertically (omni-wheels & mecanum wheels), which allow for even more possibilities.
The idea you mentioned is a drive-steer system, which is the one cars use. Check out this example of a really cool drive base, which can move freely in any direction:
http://www.technicbricks.com/2008/08/going-to-all-places-in-all-directions_29.html(2 votes)
- I am going to attempted, it I m currently building a qaudcopter and this experience may help(1 vote)
- Can the creator of this bot email me and help me out?(1 vote)
- Wait, so we need a camera, a hairdryer, a taplight, and an alarm clock. Is there something I am missing? And do we need the brands that he shows? And at about, he starts using alligator clips. Is all the wiring safe for a 7 year old to do? 4:30(1 vote)
- You should look at the parts list. it is SO helpful.(1 vote)
Video transcript
Yeah, we're going to try
and create a new product using the products
that we've taken apart. We're going to look at
the innovation process-- brainstorming-- and
then try and solve some of the initial
problems that we face in making these
products work together. So this is a little
digital recorder. I got it at Radio Shack. And you can see there's
the hair dryer there. And we've got a tap
light right here. And the tap light is just a
battery-powered LED light. And then we've got our zip ties. And you can see the digital
camera and the alarm clock. And we're trying to find ways to
make these work together and do something useful for us. So we're going to take
out our sketch pad and start drawing out
different concepts that we might be able to
make with these things. So the tap light-- I like the
dimensions of the tap light so I'm going to try that first. And we're going to use the--
the hair dryer has motors so we know the motors can blow
the tap light or potentially move something. So we're sketching a tap light
with hair dryer motors on it that can blow it around
and make it move. And maybe we'll use the
body of the alarm clock to create a little bot
that drives around. We'd need some wheels for that. And again, we might be able
to use the hair dryer motors or maybe the DVD player motors. So I'm interested in
creating something with a personality
that can move around, something that is able to
respond to its environment and can use the products
that we've already disassembled to
make something new. Hopefully maybe it
can take pictures and maybe record some sounds
and play those sounds. OK, now that we
have our objectives, how do we make it work? So what we're going to do is,
let's just isolate each one. To move around, we can
use the hair dryer motor, and we know that moves. And we could use two
of them and maybe use them to blow air
to move our device. Or we could turn
a wheel with them. And to interact with
the environment, we need some sort
of switch or sensor. So we maybe could use the
switches from the alarm clock so that if it hits
a wall or something, it can back up and turn around. And we can use our camera and
sound card to record the images and sound. But how do we control
all of these things? Well, we're going to
need a microcontroller. And we've got-- we
selected a microcontroller. And we've got our camera
and our sound card and our motors from
our hair dryer. And then of course,
we have our tap light. And we probably could
use the tap light as our body to put
everything together in. And we need something
to power all this. We need batteries. One of the first issues
we're going to run into is that we think the
motor's run on 12 volts. We know that the sound
card runs on 9 volts because that's the kind
of battery it needs, and the camera takes 4.5 volts. And the microcontroller,
our Arduino, takes 5 volts. So everything's running
on different voltages, and we have to find a way to
control all of those voltages and get everything
to work together. So, we can do that with
a motor controller. The motor controller will
provide different voltages for us to run on
and allow us to run our high-current,
high-voltage motors and control them with our
low-power, low-current, low-voltage Arduino. So that's why we need
the motor controller, and we go into more detail on
that in the motor controller video. So let's get started taking
our hair dryer motor apart, or taking it out of the
hair dryer, I should say. And since that's
going to be what we're using to move
our craft around, we want to start to
experiment with it and see how much power
it's going to require and how much torque it's going
to have and things like that. All right. so we're going
to experiment with our motor and see what it's going
to take to power it. We've got our alligator
clips connected. And we're going to use a
1.5-volt AA battery to see if we can make the motor turn
and to kind of get a sense for how much air it will
pull through it at 1.5 volts. So we've got a little piece of
plastic here to test the motor. So we're running it, and
we're holding the plastic up, and you can see it's not
moving the plastic at all. So that's not going to work. We're going to need
more volts than that. And we can increase the
voltage by combining the cells in a battery holder,
and that allows us to wire the cells
in series so we go from 1.5 volts
to over 12 volts because those cells are new. So let's see what impact
that has on the motor. OK, so we're
connecting our battery to our hair dryer motor. And whoa, you can see it's
moving much more quickly now. Now it'll push the plastic
completely out of the way. And we're getting a fair
amount of air coming out of it. But I don't think we're going
to use this method for moving our craft because, even
though it's blowing a fair amount of air,
it only works really efficiently in one direction. In the other
direction, it doesn't work as well because
it's only meant to blow air in one direction,
out of the hair dryer. OK, so let's determine the
actual specs for our motor so we know exactly
what we can run it on and how much voltage it needs. To do that, we're
going to need to remove the propeller and the outer
housing around the motor. So we're just going to trim that
off with our hack saw there. And we're time
lapsing this so you don't have to sit
through all of it. But in any case, we're going
to trim the propeller off. And then it's a
really tough thing to get off because it's
friction fitted on to this brass fitting on the end of the motor. And so it's really hard. They definitely did a
good job of press fitting that onto the brass fitting
so that it won't come off as the hair dryer moves around. So we're taking our
nipper pliers here, and we're just going to trim
the rest of the propeller off so we can get to the motor. And we'll move the
end of it off there and then unscrew the last two
screws and slide the ends off. And then we'll take
a look at our specs. OK, we've got our motor here. Let's flip it around. See if we can find the
specifications on it. And yeah, there's some
printed text right here. OK, so we can type that
printed text into the computer and determine what
kind of motor this is and what the specifications are. So it's always good to type in
the actual name of what you're looking for when you type
in your part list there. So we've got a Kysan
specification sheet. This is actually
a Mabuchi motor. And we'll go through and
we'll see if we can find it. It's right there,
the 2073 model. So our voltages,
operating voltage is between 9 and 24 volts. Nominal voltage is around 20. With no load, the
motor will spin at 17,200 rpm, which is very
fast, at a current of 0.2 amps. And we're always going to
be operating under load, so we'll always be pulling
more than 0.2 amps. The speed of the
motor can-- you know, at maximum efficiency
it's around 14,420. And then we've got a current
at that speed of around 1 amp, and that's under load. And then the torque
is 9.49 newton-meters, or 96.7 gram-centimeters. And that's the twisting force
that the motor can generate. And so that's an
important number to know. It does look like
that's going to be enough to move our craft
around since it's not going to be very heavy. And then the motor can generate
an output of 14.3 watts. So the key number that we
need to take out of this chart is the voltage. We need to make sure
that we're operating within the voltage envelope
that the motor can run on. And if we use our batteries
together in series like we did when
we were testing it, we can operate at
around 12 volts, which is between the 9
and 24-volt range, and should be fine
for us to run at. Now we're going to control
the speed of the motor using our Arduino and our
motor controller. So the Arduino is
going to send what's called pulse-width
modulation to the motor. And that's going
to change the speed and make the motor run much
more slowly than it would if it was just running
with straight current.