Ultrasonic Demo

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Internet of Things: Sensing and Actuation From Devices

87 calificaciones

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University of California San Diego

Internet of Things: Sensing and Actuation From Devices

87 calificaciones

Have you wondered how information from physical devices in the real world gets communicated to Smartphone processors? Do you want to make informed design decisions about sampling frequencies and bit-width requirements for various kinds of sensors? Do you want to gain expertise to affect the real world with actuators such as stepper motors, LEDs and generate notifications? In this course, you will learn to interface common sensors and actuators to the DragonBoard™ 410c hardware. You will then develop software to acquire sensory data, process the data and actuate stepper motors, LEDs, etc. for use in mobile-enabled products. Along the way, you’ll learn to apply both analog-to-digital and digital-to-analog conversion concepts. Learning Goals: After completing this course, you will be able to: 1. Estimate sampling frequency and bit-width required for different sensors. 2. Program GPIOs (general purpose input/output pins) to enable communication between the DragonBoard 410c and common sensors. 3. Write data acquisition code for sensors such as passive and active infrared (IR) sensors, microphones, cameras, GPS, accelerometers, ultrasonic sensors, etc. 4. Write applications that process sensor data and take specific actions, such as stepper motors, LED matrices for digital signage and gaming, etc.

De la lección

DragonBoard™ 410c Monitoring and Control

Its time to expand on what we did in Course 2! That being said, I am sure you all had a blast creating your server and checking the status of various components on your board. What if I told you we can use some of these ideas to also control peripherals on your board! Well that is exactly what we are going to do in this Module. Its time to mix your software knowledge with your hardware skills to create a system that can both receive and send information using HTTP! Buckle up because we are about to introduce you to a new sensor while also providing you with everything you will need to officially use the internet for controlling your things (IoT pun)!

Introduction to Lesson 11:23

The Ultrasonic Sensor6:17

Ultrasonic Application8:26

Ultrasonic Demo7:05

A look back at Lesson 12:34

Conoce a los instructores

Ganz Chockalingam
Principal Engineer
Qualcomm Institute of Calit2, UC, San Diego
Harinath Garudadri
Associate Research Scientist
Qualcomm Institute of Calit2, UC, San Diego

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.

The last two pins are going to the ultrasonic.

Now we have this purple wire.

This purple wire is hooked in to pin 33 also on the code and

33 goes in to one of our amplifiers.

You can follow this brown wire and then right behind the ultrasonic sensor.

We have that hooked into the trigger pin because we need to amplify the voltage

a little bit in order to control this particular sensor.

Last one is the input into the board.

So, this is how we collect the data from the sensor after we trigger it, and

this is this blue wire.

It's coming out from the echo pin on the sensor.

And then going into pin 32, right?

So all of the pins that we are using are 34 for the green LED, requires amplifier.

I'm sorry. 24 for the green LED requires amplifier.

26 for the yellow LED requires amplifier.

>> 34.

>> 34 for the red LED, also requires amplifier.

And pin 33 for the trigger pin on the ultrasonic sensor,

which requires an amplifier.

Last pin, 32, which is the input from the echo pin on your ultrasonic sensor,

and that does not require an amplifier.

So now that we have all this set up.

I think we are ready to run the application

on our Android operating system.

So Ara of course already pushed the application over.

So it's on our board and you can kind of see it up here on the screen.

Ara's opening up the application called Ultrasonic Sensor.

So we put a little button there.

So right now the Ultrasonic's off.

>> Are you guys ready >> Ready.

>> Ready all right, turn it on.

>> So you see it's reading a big number but now we're going to test it out.

We're only gonna use the LED.

So let's take a look at what happens when I put my hand out here.

So that should be of more than 30 centimeters as I bring it in.

We get the green one on.

Bring it in a little closer.

Yellow starts turning on and

a little closer- >> Might be a little too close to that.

Or maybe the red is lighting up, it's just we can't see it.

Oh yeah, there we go.

>> There we go.

All right so, bring my hand out here.

Bring it in closer.

Triggers at 30.

Little close.

Yellow turns on at about 20.

>> And there's red.

>> And then there's red as I get in closer to ten.

Pull it away, off.

Last time here, let's check it out.

Green, All right.

Okay, cool.

Perfect! So there you go.

You have your ultrasonic sensor.

Remember, this is not exactly the highest quality ultrasonic sensor.

>> Exactly. >> But as you see it still works.

>> Also remember this psm that we calculated is a little off.

>> Yeah.

>> So, obviously we're also not accounting for like, the friction or whatever.

There's a lot of variables in this so this is more of an approximation.

>> And you know, I mean you can see that there are obviously some errors in here

but for the most part it's working.

We're in a studio right now,

there's got to be frequencies all over the place flying around.

So this is, it's gonna be picking up balls from everywhere, you know

>> On a qualitative level though, it does

>> Yeah, it's cool.

>> It functions as it should.

>> There we go, all right cool.

Well, we will see you in the next lesson where we.

Remember, this is just a bonus lesson, right.

>> Yeah. >> So we'll see you in the next

lesson where we go over the server for controlling devices.

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