Using PullUp and PullDown Resistors on the Raspberry Pi

When you start out creating circuits with the Raspberry Pi and its GPIO pins, there’s an unexpected but important concept to understand, called “floating”. A Simple Circuit Imagine you’re creating a circuit using a breadboard. Something very simple… a button, some wire and a power source (like the 3.3v pin on the Pi). You just want to be able to click a button to complete the circuit. Maybe it looks something like this. The above circuit connects 3.3v, through a switch and 220Ω resistor, to pin #6. That won’t be very useful though, without a »

Building a Morse Code Transmitter on a Raspberry Pi

Last week, I made the Raspberry Pi blink an LED a few times. As thrilling as that was ;) I almost immediately wanted something more. Note: Source code for this project is available on GitHub. Goals Setup a simple circuit (LED and resistor) using a breadboard Learn about Morse Code in order to correctly translate a sentence Manipulate the GPIO pins on the Raspberry Pi to send signals at intervals Get familiar with basic Python constructs, like dictionaries, functions and loops Setup To do this, a few things are necessary: Install Raspbian on the Pi (comes with Python 3 preinstalled) Get »

How to Access Your Raspbian Desktop on the Raspberry Pi from Another Computer

When I want to play around with the Raspberry Pi, I typically end up on the floor in front of the TV (my “spare” monitor). I’m surrounded by HDMI and LAN cables, a power adapter and mouse/keyboard receiver wires, and if I don’t clean them up the 2 yo will make me wish I had when he gets up the next day. Fortunately, I’ve found a better option. In only a few relatively easy steps, you can create a setup that allows you to access the Raspbian desktop on your Pi from any machine in your »

Hello World for the Raspberry Pi (Making an LED Blink)

I finally unboxed my Pi a few weeks ago, and since then I’ve been learning some Python, which is the primary language of the Pi. You can do fun things with it out-of-the-box, like running and modifying the Python games that install with Raspbian (as well as writing your own), or playing around with MIT’s Scratch program (which also comes preinstalled). Or you could try another OS, like the OpenElec media platform that turns your Pi into a photo gallery / movie streamer (something a few of us were playing around with at the last AkronCodeClub meetup). But a »

A Tail of Recursion in Erlang (a C# developer's observations)

A group of us at VHT has been meeting weekly, reviewing some Erlang basics and running through examples. Even though it means giving up a lunch hour, over a dozen people have still been showing up to learn and help each other. Two of us were recently challenged to figure out a couple problems in Erlang without using obvious built-in functions: Determine the length of a list. (without using length([1,2,3]).) Reverse the list. (without using lists:reverse([1,2,3]).) We looked into it, and even shared what we found with the group a week later. This »

Learning Python for the Raspberry Pi

Once you’ve connected the peripherals, installed NOOBS, and gotten your Raspberry Pi up and running, pat yourself on the back and take a moment to bask in the glow of the large raspberry on your Raspbian desktop. Whee. Okay, that’s enough gloating, ya narcissist. So now what? Choosing a Language After getting my first Raspberry Pi 2 up and running last weekend, and taking some cursory glances at the sample apps, I wanted to get into some actual development. After all, if we can’t tell it to do anything, then it’s not much more than a »

Getting Started with the Raspberry Pi 2

I got a Raspberry Pi 2 for Christmas, and finally took it for a spin this weekend… just as the community is getting ready to celebrate the Pi’s 4th birthday. After using it for a few hours, here’s what I’ve learned so far. Invest in a Starter Kit The base Raspberry Pi 2 board is only about $35, but it comes with nothing else, not even an ac adapter. If you happen to have spare parts lying around, this may not be a problem. Unfortunately, I dumped my boxes of computer parts years ago when I stopped »

Building a Model 4-Stroke Internal Combustion Engine (your car explodes gas 50x a second, how cool is that?!)

Garage sales are great for finding random, interesting things to do with the kids, usually for dirt cheap. Unless you run into one of those garage sales where everything’s only 5% off the original retail price… Folks, your garage sale is one step before the dumpster. Don’t try to fund next summer’s vacation. Make a few bucks, clear out the basement and enjoy a night at the movies. Splurge on a large popcorn and 80 oz drink. Thank you, that is all.* Last summer, I found this “Smithsonian Motor-Works” set for $5, which I figured was a »