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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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LED eyes
In this video we create and wire Bit-zee's tri-color LED eyes. Created by Karl Wendt.
Want to join the conversation?
- How do they make multi-colored Light Emitting Diodes?(3 votes)
- Multi-color LEDs are three separate silicon chips packed into one package. One red, one green, and one blue LED. If you have a diode with a clear plastic package/lens, hold it under a magnifying glass and you can see the silicon chip(s).(5 votes)
- Are there any detailed instruction for Bitzee?(2 votes)
- I believe that these videos are the only instructions here on Khan Academy. In my opinion, these videos are pretty detailed...(3 votes)
- It would be great if there was a manual to supplement the videos or is there ?(2 votes)
- Why can't we do more colours for the LED eyes?(2 votes)
- So what does a breadboard do anyways?(1 vote)
- he read the list and said for example a5 but but it in c8(0 votes)
- Can you make the eyes different things like cameras instead of bottle caps with LED lights?(0 votes)
- Yes, but it will require additional and different wiring for the cameras.(1 vote)
Video transcript
OK, so now we're going to
give Bit-Zee some eyes. We're going to use tri-color
LEDs and bottle caps. We're matching the
LED up with a drill bit so that we can put a hole
in the center of the bottle cap, and the LED will basically serve
as a pupil and the bottle cap will serve as an iris. So we're going to
trim the excess off of the bottle cap there, the
scrap that the drill bit left. And then we can put our
LED in the middle of it, and we've got a Bit-Zee eye. OK, so the LED has four
legs, and the long one is the positive. And that's important,
because we've got to wire the LED
with the right polarity. So we've got our two LEDs
put onto our bread board in the far, far
right and left sides. Now we're connecting
three transistors. These transistors are the
same transistors, the NPN type transistors, that we
used for our sound module and for our camera to
turn them on and off and trigger their functions. So these LEDs are going
to trigger the red, blue, and green lights
in the LEDs that are on both the
right and left sides. So we're using 1K ohm resistors
and that'll be for our base on the transistor. And that's the center wire. And right now, we're
just moving the wires over for our IR sensor so that
we have a little more space. And then we're going to put
another 1K ohm resistor there again, going to the center
pin on our resistors. And so now that
we've got that done, we're going to take a
look at our pin-outs. And you can see that
A1 is the green LED. A0 is the red LED, and
A2 is the blue LED, so we want to make sure that
we wire those up accordingly so that we can get the
right colors to turn on when we want them to. So we're using a green wire
to indicate the green LED, and that'll go to
the transistor that switches on and off the greens. And then we're using a red
wire for the one that's going to switch on
and off the reds, and a black wire
for the one that's going to switch on
and off the blues. I didn't happen
have a blue wire. And you can see how those are
connected to the resistors. OK, and so now we have
a 220 ohm resistor, and we're going to connect
that to the positive leg or the long leg of
both of our LEDs, and this is going to protect
the LEDs from drawing too much current and burning out. You can change the
value of the resistor. We'll talk in another
video about how to determine the
right resistor value, but there is some
variation, and if you use a resistor with
a higher value, you're going to
get a dimmer LED, and if you use a lower value,
you'll get a brighter one. OK, so we've got
those two in place. And just fitting them with
our needle-nose pliers. Sometimes it's hard to get
the leads to sit in place all the way. Now we're going to run
our positive wire up from our power
distribution board below. That's the little board that
we made in a previous video. And we'll connect it to the same
row as our 220 ohm resistor, and let's run one for each LED. So there's one on the right
side and one on the left. And we'll connect the
one on the right side, again, to that 220 ohm resistor
and then sort of push it out of the way. OK, so the positive
power has been fed. Now, what we're
going to do is we're going to connect the ground
wire from the power distribution board below to our LED that's
on our far left-hand side. And that's just
going to the left leg with the transistor
on the left-hand side, and that's the
transistor that's going to switch on and off our green. And so we have another
ground wire here, and we can run that ground
wire up from our Arduino, because there's a
ground port there, and connect it to our
transistor on this I side. And now we're going to
distribute the ground wire from the far left-hand
side transistor to the one in the middle. And this uses the
same type of wiring that we used before when we did
our sound module and cameras, as I said before. So now we're going to
connect the resistor that's switching the red LED to
the red LED pin, which is the one on the far left when
we're looking at the LED here. And I think I had already
wired the green one. You can see it down
there at the bottom. It connects to the wire on the
far right on that same LED. And now we're going to run
the wire for our blue LED, and that's just the one
right next to the green. So we're stripping
the wire there, and now we're connecting
it, and connecting it to the transistor that should
switch that on and off. And actually, I believe we
downloaded some code for this, just some sample
code, and you can see it's just to make the
LED light up and flash. And you can get this code
from Arduino's website. It's just an LED
flash, and so you need to make sure that it's
set up to the right pin-outs that we've listed there. But in any case, that one works. So now we're going
to connect that LED to the one on the other side. So we're going to
take our green wire and run it over to the same lead
on the LED on the other side. And so you'll see it
only lights up green now. It doesn't light
up red and blue, because we haven't run
the red and blue wires. So as it flashes,
it goes through red, blue, green,
red, blue, green, and you can see that only
the green is showing up. So now we're going to
run our other two wires. We're going to run our red
wire and our blue wire, and so the eyes should flash
in synchronous together. So now we're going
to run our red wire, and you should be able to
see the red wire caused the LED to flash red and
green instead of just green on the right-hand side. So there you go. You can see it's red and
green, but we're still missing our blue. I'll let you take a look at
that for just a second so you can see the difference
between each eye as they go about flashing. So the one on the left is
going red, green, and blue, and then the one on the
right is just red and green. So now we're going to
connect our final wire, and that will allow us to light
up in red, green, and blue. One thing I want to note
is that the blue LED is not as bright as the
red or the green, and you can change that by
putting resistors on each LED instead of on the
one positive out. You can put resistors on each
LED that are different values and make the blue
brighter and the green and the red less
bright so that they're all sort of equal, if you want. So one thing you can see there
is that when I bumped it, the lights turned off. And so it's a temporary
connection on the bread board, and it's possible
things will come loose, so you kind of have to
keep an eye on that. But it does allow
you the flexibility of changing the configuration
and trying different things.