The Occidentalis Linux distribution for Raspberry Pi (and Raspbian as of Dec 2012) includes support for the DS18B20 1-wire temperature sensor. These sensors come in a small three pin package like a transistor and are accurate digital devices.
In this lesson, you will learn how to use a DS18B20 with the Raspberry Pi to take temperature readings.
Since the Raspberry Pi has no ADC (Analog to Digital Converter), it cannot directly use an analog temperature sensor like the TMP36, making the DS18B20 a good choice for temperature sensing.
This incredibly small stereo amplifier is surprisingly powerful – able to deliver 2 x 3.7W channels into 3 ohm impedance speakers. Inside the miniature chip is a class D controller, able to run from 2.7V-5.5VDC. Since the amp is a class D, its incredibly efficient (over 90% efficient when driving an 8Ω speaker at over a Watt).
This amplifier is perfect for portable and battery-powered projects. It has built in thermal and over-current protection, but you really have to drive it hard before it even gets warm! This board is a welcome upgrade to basic “LM386″ amps!
Stepper motors fall somewhere in between a regular DC motor (Lesson 9) and a servo motor (Lesson 8]). They have the advantage that they can be positioned accurately, moved forward or backwards one ‘step’ at a time, but they can also rotate continuously.
In this lesson you will learn how to control a stepper motor using your Raspberry Pi and the same L293D motor control chip that you used with the DC motor in Lesson 9.
The Lesson will also show you how to use an alternative driver chip, the ULN2803.
For this project, it does not really matter if you use a L293D or a ULN2803. The lower cost of the ULN2803 and the four spare outputs, that you could use for something else, probably make it the best choice if you don’t have either chip.
The motor is quite low power and suffers less from the surges in current than DC motors and servos (which use DC motors). This project will therefore work okay powered from the 5V line of the Raspberry Pi, as long as the Pi is powered from a good supply of at least 1A.
We have a new alpha release of the Rapsberry Pi WebIDE ready to go. This latest version is primarily bug fixes, but it does have one new feature! We’ve added the ability to create folders at all levels of your project to help with organization of those more complex projects.
The new changes for the 0.3.2 version of the WebIDE are as follows:
Navigator: Add ability to create folders at all levels.
Debugger: Fix display of local vs global variables.
Terminal: Set terminal width based on containing parent, use entire width and height.
The Raspberry Pi WebIDE includes an advanced, yet easy to use tool, to help you work through code that you’ve downloaded or written in Python.
If you haven’t used a debugger, either on the command line or in an Integrated Development Environment (IDE), hopefully this guide will help you understand why you’d want to do so, and how to effectively debug your code.
This is my first video in a new series that will cover every aspect of the Adafruit Learning System Raspberry Pi WebIDE. The WebIDE is still in the early development phase, but we are rapidly packing in great new features, and squashing bugs. Even though it is still in Alpha, this first video shows you how incredibly easy it is to install the WebIDE onto your Raspberry Pi. The goal is to release a new video each Friday to cover a new feature of the WebIDE.
This lesson describes how to control both the speed and direction of a DC motor using Python and a L293D chip. In Lesson 8, we used the Pi to generate pulses to control the position of a servo motor. In this lesson we use pulses to control the speed of a regular DC motor and the L293D motor control chip to reverse the direction of the current through the motor and hence the direction in which it turns.
I2C is a two-wire serial bus interface historically used to communicate between different components of an electronics device on the same circuit board. Amidst the rise in hobbyist/open electronics and the “Internet of Things”, I2C has also become popular as a well-defined communication technology between off-the-shelf electronic project components of the type commonly sold at Adafruit, Sparkfun, and Newark. Accelerometers, NFC chips, LED displays, and many other types of devices are available using this interface, allowing hackers to easily communicate bidirectionally with special-purpose components from their micro-controller or full-fledged computer projects.
One example of such a component that is fun to play with is the Adafruit 8×8 LED Matrix w/I2C Backpack. This device is pretty much exactly what it sounds like, 64 LEDs arranged 8×8 that can be individually controlled over an I2C interface via an HT16K33 integrated circuit. Starting with a few of these devices and a Raspberry Pi, I decided to delve into what it would take to drive the LEDs from my favorite language, Go.
I started by soldering the LED matrix devices to their backpacks as described here:
Adafruit provides great support for controlling these devices and others that they carry from within Python code (available via GitHub (https://github.com/adafruit/Adafruit-Raspberry-Pi-Python-Code) and this code works well for spot-checking that the device has been successfully connected and is in working order. All of my soldering went okay and the device worked (though I did have to modify the Python code slightly because at the time it assumed it would be driving a LED matrix on I2C bus 0, but it should have been using bus 1 because the I2C bus number designations flipped around the time the newer 512MB Raspberry Pi devices became available and my Pi is a 512MB model).
What’s better than a single LED? Lots of LEDs! A fun way to make a small display is to use an 8×8 matrix or a 4-digit 7-segment display. Matrices like these are ‘multiplexed’ – so to control 64 LEDs you need 16 pins. That’s a lot of pins, and there are driver chips like the MAX7219 that can control a matrix for you but there’s a lot of wiring to set up and they take up a ton of space. Here at Adafruit we feel your pain! After all, wouldn’t it be awesome if you could control a matrix without tons of wiring? That’s where these adorable LED matrix backpacks come in. We have them in two flavors - a mini 8×8 and a 4-digit 0.56″ 7-segment. They work perfectly with the matrices we stock in the Adafruit shop and make adding a bright little display trivial.
The watch kit already ships with style to spare, but that’s no reason to limit yourself to the included watch band when you can make one.
Here are the steps I took to create the “Circling the Square” TIMESQUARE Watch Body. As I guide you through the steps I followed, I will share plenty of tips and tricks for how you can design your own!
We have a new alpha release of the Rapsberry Pi WebIDE ready to go. This version includes a major new feature that allows you to debug your python programs. This is a real-time step debugger, with breakpoints, output, etc.
The new changes for the 0.3.0 version of the WebIDE are as follows:
Python step debugger
Node.js update to 0.8 from 0.6 for faster navigation, and page loads.
Package node binaries with the WebIDE for faster, and easier installs
NOTE: To take advantage of the updated node binaries, and increased speed of the WebIDE, you’ll want to do an uninstall/installation, as the binaries are configured during the installation process, so updating within the editor won’t pick those changes up.
Here’s a screenshot of the debugger in action:
Upgrading from 0.2.0 and higher
You can upgrade from 0.2.0 and higher from within the editor. If you’d like the increased speed using the new node binaries, you’ll want to uninstall/install again.
Ensure that your code is safely saved in your repository at bitbucket.org.
Login to the editor.
Click Update in the upper right.
Update should take about a minute.
Upgrading From 0.1.9 and lower
To install this new editor, you’ll want to completely remove your old editor, and run the installation script again.
Ensure that your code is safely saved in your repository at bitbucket.org.
Uninstall using the following script
curl https://raw.github.com/adafruit/Adafruit-WebIDE/release/scripts/uninstall.sh | sh
Either make sure there are no rogue node processes running, or restart your Pi.
Install the new and improved WebIDE
curl https://raw.github.com/adafruit/Adafruit-WebIDE/alpha/scripts/install.sh | sudo sh
By popular demand, we now have a project tutorial for how to make your own programmable, ultra-blinky LED belt. Perfect for parties, raves, parades, weddings, funerals, and bar mitzvahs. Wear it with pride, wear it with blinky! Follow this tutorial to build your own heirloom LED belt, and hand it down to your grandkids.