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From the course by University of California San Diego

Internet of Things: Sensing and Actuation From Devices

84 ratings

University of California San Diego

Internet of Things: Sensing and Actuation From Devices

84 ratings

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.

From the lesson

Bluetooth Remote

If you thought the IR remote module was fun, this will take your wireless control of the DragonBoard™ 410c to a whole new level. Here we will use multiple devices to communicate and control peripherals using Bluetooth. We will walk you through the steps we took in order to send and receive data through the Bluetooth modules on multiple devices. By the end of this module you will be able to control a variety of components (including GPIOs) on your DragonBoard™ 410c from other devices using close range Bluetooth connectivity. We are very excited to share this code with you, and we are even more excited to see all of the cool stuff you will all come up with when you are finished with this Module.

Introduction to Lesson 21:59

Bluetooth Manager5:50

GPIO Input Parser2:36

Bluetooth Receiver / Remote7:06

A look back at Lesson 21:53

Meet the Instructors

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

Finally, the funnest part, right, the most fun part of this-

>> The most anticipated part,

that's the code word.

[LAUGH] >> Yeah, oh man, my blood is boiling.

Yeah, so we are going to show you the demo of this

application that we've been walking you through this whole entire module.

Finally it's up.

So, first off what we need to do is we need to kind of walk you through

the circuit.

Now, you're going to recognize this circuit.

Throughout the course we've used it.

It's the amplifier circuit.

So, as you see we have our NTE-987, the single rail, quad amp.

You know, because we are powering LEDs, we are going to use that.

Now, let me just walk you through the wires that we have set up here.

We have this black one right here, which is placed into our pin 40,

which is one of the grounds that are on the low speed expansion header.

Going into our rail here, and then this vertical rail, and

it is being shared all the way across the board.

So the cathodes from the three LEDs are also grounded.

Now, moving onto the power,

we need to power this amplifier cuz we wanna bring up the voltages from the pins.

So we have the red one right here, 39, 38, 37, so yeah.

So, the 37th pin on the lowest speed expansion header is your five volt

power that is going into the rail here, and

that is the only place we actually need the five volts which is for our amplifier.

Next come the three LEDs that we are going to be powering.

Now I kind of used the colors for the LEDs so

you can kind of trace the green wire from pin 24.

And this is also in the code, too.

You'll see it in the code.

But pin 24 places into the input of one of our amplifiers.

Follow this brown wire over to the green LED, there you go.

Yellow is in pin 26.

Follow pin 26,

the wire into the input of one of our amplifiers, out to the yellow LED.

And the red, same thing, but from pin 34.

Pin 34 goes to the input of an amplifier, out this way to the red LED.

Now, each LED is also paired with its respective resister, somewhere between 200

and 500 you're usually safe, keeping your resistors safe from burning out.

Right, so, the circuit is setup.

We are connected to the dragon board.

The dragon board has had,

we already pushed the applications on to the board and your phone, right?

>> Yeah. >> Yeah.

>> So one thing to make sure, if you recall in the previous video,

to properly send the correct fragment.

So that means commenting out either the receiver fragment or the remote fragment,

depending on which application or which device you're porting your application to.

>> This was, we did this to make it easier for you, so

you didn't have to pull two separate applications.

But you know if you're skipping around videos and

you don't exactly hear us saying this,

then you might end up finding yourself a little confused when it's not working.

So make sure you follow those instructions,

go back a video or two, and check out where he commented that out, and

so you have the right applications on both your devices.

So what's next, Jacob.

>> Let's do this demo.

>> All right, cool.

So let's see you power that on [INAUDIBLE].

>> So, I'm powering up my application,

it's launched here on my phone, as you can see on the screen.

[CROSSTALK] We're gonna load up the screen on the dragon board.

So right now, it's saying it's yellow, off, because the yellow is off, but

we're gonna restart the application to let you know that this works.

>> I'm reopening the application on the Dragon board.

We have it right here.

It says, Bluetooth Remote Receiver.

I'm going to open it.

>> So now, because it's turned on, or the application is on resume, it's listening.

And this only occurs when the Bluetooth is on, and as you can see on the screen,

the Bluetooth four, the Dragonboard is already turned on.

>> Yeah, sorry I was gonna say,

our studio's doing something really cool for us.

We're gonna have the LEDs here showing you while Jacob's hitting the buttons, so

you're gonna be able to see.

And look, hands clear.

We're not messing with you here.

>> Yeah. [LAUGH] >> So

before you enable it to work, you have to make sure that it's connected.

So we have this Bluetooth scan method on the remote.

As you can see, my device is already paired.

But just to make sure, I'm going to make it pair again.

Wait a couple of seconds to let the pairing happen, and

then we can test the demo.

So first we're gonna turn on the green light.

>> There you go, and it's on, how about that?

>> Turn it off.

>> Good job.

>> Turn on the red, turn it off as well.

>> Nice.

>> And then lastly, yellow.

And off.

>> Let's turn them all on.

>> Yeah, so actually if you see on the screen,

on the screen, it will display the last message.

So, what we're gonna do now, is we're gonna turn on all the LEDs.

So, turn on yellow, turn on red, turn on green, and

appropriately the lights are on.

So, we're gonna turn them off.

Off, off, and off.

All right, good job.

>> Cool.

>> So now, again, we just showed you how to send that information.

You know, you take everything that we've done throughout,

sorry I'm looking over here.

>> [LAUGH] >> Take everything

that we've done throughout this entire course and we modified.

We started I mean weeks ago modifying the boot script, right?

>> Yep. >> That was just to get the Android access

to your GPIOs, then we got the access.

We turned them on through the terminal.

We created an application, made it blink a little bit.

After that, we did the step remoter, then the IR remote,

now we're on a bluetooth remote.

So, I mean, the progress is amazing.

This is really cool.

>> Yeah.

>> You guys can kind of play around with it some more.

Get some cool stuff going, and

we look forward to seeing all of the cool stuff you all come up with.

>> Stick around, and we have one more module left

where we're gonna kinda do this with a really cool server.

That's coming up, right.

Take care.

See you soon.

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