It is now time to demo this ultrasonic.
So kind of just a little recap of what we've done up until this point is we kinda
explained what the ultrasonic is.
How it works little bit in a higher level.
And then we went through the code that Arra prepared for y'all to pull from git.
Good? All right.
Cool. So time to dive in here.
I'm gonna kinda, before we open the application and
get everything running on the board, I wanted to just trace out all these wires.
We do this usually whenever we have a circuit on the table.
So it's kind of become convention at this point.
>> [LAUGH] >> So if you take a look at our circuit
here, >> You
can see that we have our ultra sonic hooked up.
And from I guess, your view, right to left, you have ground echo trigger.
Ground, echo, trigger, vcc.
So, kind of there's some little hidden wires back here and
how we have everything set up, but let's talk about these colors here.
Now this whole board is of course powered and grounded.
So we have our ground hooked into our pin 40 over here.
And this ground is just kind of laced all the way across the board.
So every vertical rail has ground on it.
Then we have the board powered, which is hooked into right here and
this is hooked into pin 40, 39, 38, 37.
So this is our five volt power and that is also providing power to all the rails.
We just kind of laced all the five volts across all the rails here as well.
So, that's power and ground on 40 and 37.
Then from what you learned in module three, how to build the amplifier.
We're using the amplifier strictly for controlling the LEDs and the trigger pin.
So we are using all four of the amplifier nodes on this particular chip.
But I mean you could still run the ultrasonic sensor without the led's and
all you would need to use is one amplifier.
Cuz all you really need it for is the trigger the echo is in fact an input.
So now let's go over that.
Right here we have this green wire,
which is coming out of pin 24 on your dragon board.
It's going over here to the input of one of our amplifiers, the NT-987.
And then this brown wire here is tracing across over into the green LED.
All this was gone over in the code.
Pin 24 is for the green light and the green wire.
Next you have the yellow light, and the yellow light is coming out of pin 26,
as mentioned in the code.
Going into the input of one of our amplifiers.
And then the output of that one, feeds over here into the yellow light.
Last one is the red light.
Now the red light, we have another red wire,
which don't get it confused with the five volt at 37.
This one is coming out of pin 34 in the DragonBoard and 34,
tracing it over to the imput of one of our amplifiers, And
then the output right here goes over into our red LED.
Of course each one of these LEDs has its respective resistor, somewhere between
200 and 500 is usually safe to make sure that you don't burn them out.
And then they're all grounded over here to the rail.