## Introduction to Microcontrollers - Button Matrix & Auto Repeating

November 12, 2013

Too Many Buttons, Not Enough Inputs

Assigning one GPIO input to each button can use up a lot of GPIO pins.  Numeric input requires at least 10 buttons, plus however many additional control or function buttons.  This can quickly get expensive, GPIO pin-wise, and also connector-wise if the keypad is off the uC PCB as it often would be.  A very common response to this expense is to wire buttons (keys, etc) in a matrix.  By connecting our buttons in an...

## Energia - program a TI MSP430 using Arduino sketches

November 5, 20131 comment

I started tinkering with microcontroller a couple of years ago with an Arduino Uno.  I had a little experience with C, so programming in the Arduino environment has been relatively easy and straightforward for me.  My code is not necessarily elegant or efficient, but I can usually figure out how to make an Arduino do what I want it to do eventually.  A lot of credit to the Arduino userbase, as it is very easy to figure most things out with a quick Google...

## Embedded Systems - free EdX course by UT-Austin!

October 29, 20131 comment

I was very excited to see that there will be an Embedded Systems class available for free at https://www.edx.org/course/utaustin/ut-6-01x/embedded-systems-shape-world/1172

It's free to sign up and take the online class at the EdX website.

More exciting is that the class is based on a TI Launchpad Tiva microcontroller development board.  The Tiva Launchpad features an 80-MHz ARM Cortex M-4 MCU with 256 KB of flash storage, 32 KB of RAM and 43 general purpose I/O pins.

## Introduction to Microcontrollers - Buttons and Bouncing

What Is A Button?

To your hardware, that is.  As discussed in Introduction to Microcontrollers - More On GPIO, a button (or key, or switch, or any form of mechanical contact) is generally hooked up to a microcontroller so as to generate a certain logic level when pushed or closed or "active," and the opposite logic level when unpushed or open or "inactive."  The active logic level can be either '0' or '1', but for reasons both historical and electrical, an...

## Arduino robotics #4 - HC-SR04 ultrasonic sensor

October 20, 20131 comment
Arduino Robotics

Arduino robotics is a series of article chronicling my first autonomous robot build, Clusterbot.  This build is meant to be affordable, relatively easy and instructive.  The total cost of the build is around $50. 1. Arduino robotics - motor control2. Arduino robotics - chassis, locomotion and power3. Arduino robotics - wiring, coding and a test run4. ## Arduino robotics #3 - wiring, coding and a test run October 17, 2013 Arduino Robotics Arduino robotics is a series of article chronicling my first autonomous robot build, Clusterbot. This build is meant to be affordable, relatively easy and instructive. The total cost of the build is around$50.

1. Arduino robotics - motor control2. Arduino robotics - chassis, locomotion and power3. Arduino robotics - wiring, coding and a test run4.

October 16, 2013
Arduino Robotics

Beginner robotics is a series of article chronicling my first autonomous robot build, Clusterbot.  This build is meant to be affordable, relatively easy and instructive.  The total cost of the build is around $50. 1. Arduino robotics - motor control2. Arduino robotics - chassis, locomotion and power3. Arduino robotics - wiring, coding and a test run4. ## Introduction to Microcontrollers - More Timers and Displays October 15, 20131 comment Building Your World Around Timers By now you have seen four different ways to use timers in your programs. Next we will look at some ways to produce the effect of multiple parallel streams of work in your program with the help of timers. This effect is only an appearance, not a reality, since a single microcontroller (one core) can only run a single thread of code. However, since microcontrollers are so fast in relation to a great many of the tasks to... ## Arduino robotics #1 - motor control October 13, 20133 comments Arduino Robotics Beginner robotics is a series of article chronicling my first autonomous robot build, Clusterbot. This build is meant to be affordable, relatively easy and instructive. The total cost of the build is around$50.

1. Arduino robotics - motor control2. Arduino robotics - chassis, locomotion and power3. Arduino robotics - wiring, coding and a test run4.

## Introduction to Microcontrollers - Adding Some Real-World Hardware

When 2 LEDs Just Don't Cut It Anymore

So far, we've done everything in this series using two LEDs and one button.  I'm guessing that the thrill of blinking an LED has worn off by now, hard as that is to imagine.  What's more, we've just about reached the limits of what we can learn with such limited I/O.  We have come to the point where we need to add some hardware to our setup to continue with additional concepts and microcontroller...

## Energia - program a TI MSP430 using Arduino sketches

November 5, 20131 comment

I started tinkering with microcontroller a couple of years ago with an Arduino Uno.  I had a little experience with C, so programming in the Arduino environment has been relatively easy and straightforward for me.  My code is not necessarily elegant or efficient, but I can usually figure out how to make an Arduino do what I want it to do eventually.  A lot of credit to the Arduino userbase, as it is very easy to figure most things out with a quick Google...

October 16, 2013
Arduino Robotics

Beginner robotics is a series of article chronicling my first autonomous robot build, Clusterbot.  This build is meant to be affordable, relatively easy and instructive.  The total cost of the build is around $50. 1. Arduino robotics - motor control2. Arduino robotics - chassis, locomotion and power3. Arduino robotics - wiring, coding and a test run4. ## A wireless door monitor based on the BANO framework June 10, 20145 comments Introduction I have been thinking for a while about a system to monitor the states of my flat and my garage doors from a remote place. Functionnaly, I wanted to monitor the state of my doors from a remote place. A typical situation is when I leave for holidays, but it can also be useful from the work office. To do so, I would centralize the information on a server connected on the Internet that I could query using a web browser. The server itself would be located in the appartement, where... ## Slew Rate Limiters: Nonlinear and Proud of It! October 6, 2014 I first learned about slew rate limits when I was in college. Usually the subject comes up when talking about the nonideal behavior of op-amps. In order for the op-amp output to swing up and down quickly, it has to charge up an internal capacitor with a transistor circuit that’s limited in its current capability. So the slew rate limit $\frac{dV}{dt} = \frac{I_{\rm max}}{C}$. And as long as the amplitude and frequency aren’t too high, you won’t notice it. But try to... ## Cortex-M Exception Handling (Part 1) November 28, 20152 comments This article describes how Cortex-M processors handle interrupts and, more generally, exceptions, a concept that plays a central role in the design and implementation of most embedded systems. The main reason of discussing this topic in detail is that, in the past few years, the degree of sophistication (and complexity) of microcontrollers in handling interrupts steadily increased, bringing them on a par with general-purpose processors. ## Reverse engineering wireless wall outlets July 19, 2014 Introduction I am improving the domotics framework that I described in a previous article://www.embeddedrelated.com/showarticle/605.php I want to support wireless wall outlets, allowing me to switch devices power from a remote location over HTTP. To do so, I could design my own wireless wall outlets and use a hardware similar to the previous one, based on the NRF905 chipset. The problem is that such a product would not be certified, and that would be an issue regarding the home insurance,... ## Introduction to Microcontrollers - More Timers and Displays October 15, 20131 comment Building Your World Around Timers By now you have seen four different ways to use timers in your programs. Next we will look at some ways to produce the effect of multiple parallel streams of work in your program with the help of timers. This effect is only an appearance, not a reality, since a single microcontroller (one core) can only run a single thread of code. However, since microcontrollers are so fast in relation to a great many of the tasks to... ## Arduino robotics #3 - wiring, coding and a test run October 17, 2013 Arduino Robotics Arduino robotics is a series of article chronicling my first autonomous robot build, Clusterbot. This build is meant to be affordable, relatively easy and instructive. The total cost of the build is around$50.

1. Arduino robotics - motor control2. Arduino robotics - chassis, locomotion and power3. Arduino robotics - wiring, coding and a test run4.