Measuring the Raspberry Pi's Current Consumption Wed, Jun 20. 2012
The Raspberry Pi has a micro-USB jack for power input. This can be used with any recent mobile phone adapter. If you use a two-part adapter, with a plug-in AC-DC converter and a USB A to micro-USB A cable, it's easy to measure the current drawn by the Pi.
To do this, you'll need a USB A male to USB A female extension cord and an ammeter or multimeter with a 1A or 10A range.
1. Remove the outer insulation in the middle of the USB extension cable. Peel back the shielding (silver braid and/or foil) to one side.
2. Cut the 5V supply wire (usually coloured red).
3. Connect your ammeter or multimeter to the cut 5V line.
4. Insert this cable between your AC-DC converter and the USB cable going to your Raspberry Pi.
So, how much current does the Raspberry Pi draw?
It looks like the Pi can draw anywhere from 250 to 500 mA in normal operation, though I did see smaller values in the early stages of startup. When idle, my Pi draws 320-380 mA; with a basic Logitech keyboard and mouse attached and in use, and with the CPU and GPU fairly active, it comes close to 500 mA.
Update: Powering the Pi from a Laptop
The fact that the Pi's current consumption is reliably under 500 mA means that it is actually safe to power from the USB port of another system. This is convenient for developers on the go: for example, I'm in an air-conditioned library escaping the current Toronto heatwave, and have my Pi connected to the back of my laptop with a micro-USB cable for power and a crossover ethernet cable for data.
New Role: Industrial Research Chair - Open Source Technology for Emerging Platforms Thu, May 10. 2012
On Tuesday, the Natural Sciences and Engineering Research Council (NSERC) announced a number of grant awards at the Polytechnics 2012 conference, including the new Industrial Research Chairs for Colleges (IRCC) grants. I am honoured to be selected as the chairholder for the NSERC Industrial Research Chair for Colleges in Open Source Technology for Emerging Platforms in the Centre for Development of Open Technology at Seneca College.
This five-year renewable applied research grant enables me to continue and expand upon the work that I have been doing, along with a talented team of research assistants, with Fedora ARM and related projects. My goal is to bring the wealth of open source software currently available for x86 PCs and servers to emerging ARM based general-purpose computers. Although ARM architecture chips are the most popular CPUs made (more ARM chips shipped last year than there are people on this planet), most of these went into dedicated devices, and ARM chips are just starting to appear in general purpose computers. In order to make the transition to general-purpose ARM systems viable, industry-standard software stacks are needed. Fedora is a perfect fit for this purpose, because it encompasses both a large collection of cutting-edge open source software and a vibrant community, and it feeds many downstream distributions and projects.
My work in this new role will start with an expansion of existing work, including operating the Fedora ARM Koji buildsystem and improving the Raspberry Pi Fedora Remix, but I will additionally be focusing on Fedora on ARM server-class systems. In future phases, this will encompass working with the Fedora ARM project to promote ARM to primary architecture status, extending existing open source system management (and possibly virtualization/cloud management) frameworks to manage high-density ARM clusters, doing field trials of ARM-based data centre solutions, and bringing Fedora to the next generation of ARM technology.
Although the majority of my activity will shift from teaching to applied research, I will continue to teach the SBR600 Software Build and Release course in order to bring the research experience back into the classroom. I'll also continue to participate in the TeachingOpenSource.org initiative. As an Industrial Research Chair, I will also have a bit more of a public-facing role, representing CDOT and advocating the use of energy-efficient systems to local SMEs.
Many thanks to Red Hat for partnering with Seneca on this initiative, and I look forward to (continuing to!) work closely with Red Hat's incredible technical staff. I also thank the many companies and organization who wrote letters of support for the grant application, and look forward to collaboration and possible future partnerships with those organizations. And I particularly want to thank Seneca for its support of applied research, my colleagues at CDOT for their encouragement and for creating such an awesome environment to do applied research, and for the team that wrote the grant application under intense pressure and tight deadlines last November.
Watch this space for updates!
Element 14's Wonderful Forums Considered Harmful Fri, Mar 9. 2012
This understandable requirement, probably a result of US legislation (and perhaps legislation in other jurisdictions?), is at odds with the Raspberry Pi's stated focus on children (hence the "considered harmful" jab).
Raspberry Pi links Wed, Feb 29. 2012
The Raspberry Pi hardware went on sale last night, and as with every other event related to the Pi, pandemonium ensued!
The educational, tech, and mainstream media is starting to take note. Here are some links to local coverage of the Pi and our work on the software for it:
- Radio Canada International - Masala Canada
- CBC News - Lang and O'Leary Exchange (segment starts at 47:05)
Update 2012-03-10 - additional links:
To clarify Seneca's involvement, because it may not be clear from the press coverage:
- The Raspberry Pi Foundation created the Raspberry Pi hardware, and has licensed its production to a pair of UK-based production and distribution companies, Farnell (which has wordwide subsidiaries including Newark here in Canada) and RS Components (Allied Electronics in Canada).
- The Centre for Development of Open Technology (CDOT) within Seneca College works with the Fedora ARM group within the Fedora Project to produce a build of Fedora for ARM devices. One of our roles is the creation and operation of the build system, a cluster of more than 60 ARM-based computers used to build the ARM software.
- My research group at CDOT and my Software Build and Release (SBR600) classes at Seneca worked together to produce the Raspberry Pi Fedora Remix, which takes the Fedora ARM software and adds a small number of additional software packages needed for use on the Pi. We tested the remix on an alpha (pre-production) board provided by the Foundation.
Information about the Remix may be found on the Seneca CDOT wiki.
Fedora ARM on the Raspberry Pi at Seneca CDOT Wed, Oct 19. 2011
What happens when you combine a $25/$35 computer, a major Linux distro's secondary arch effort, and a college that's deep into open source?
Here's a tiny video peek...
There's a lot of optimization still to be done (including X11) but look forward to a Raspberry Pi Fedora image (spin/remix), Fedora 15 for ARM, and the Raspberry Pi device itself all being available next month.
(In or near Toronto? There are three talks related to Fedora ARM and/or the Raspberry Pi at FSOSS next week).
Gnome 3: Not Ready for Prime Time in Fedora 15 Sat, Apr 23. 2011
I've been intrigued by the Gnome 3 desktop and the design decisions that the Gnome project has decided to test. Hearing some members of the Gnome community explain the design decisions in person was very interesting, and helpful when transitioning to the Gnome shell. And I'm proud that the Fedora Project is continuing to lead by incorporating new technologies and designs First.
But I've been using Gnome 3 in the Fedora 15 alpha and beta releases for a while now, and I'm convinced that Gnome 3 is not ready for prime time yet, at least as implemented in Fedora 15 (and this is completely separate from the issue of whether the Gnome 3 design changes are good or bad, and whether the Gnome community is ignoring the needs and wants of the users and downstreams -- both subjects of much debate). As one example, multi-monitor setups are not working as expected, at least for me. In fact, it's a stretch to say that they're working at all:
- On my laptop/netbook, logging in with an external monitor connected results in Gnome 3 running in degraded mode, with Gnome 2-style menus. Logging in without an external monitor connected, and connecting it after login, results in a usable configuration - at least all of the real estate is accessible.
- I run with the external display above my laptop. Maximizing a window on the external display results in it filling the rightmost 1/3 of the screen. Unmaximized windows may be moved, but only to positions where the right edge of the window is within the right-most 1/3 of the screen. You can fill the screen by placing the window all the way to the right and dragging a corner to the left side, though. There are many other behaviours which are just weird.
- The Activities button is on the laptop screen, but the touch-to-activate-Activities corner is on the external monitor.
- Rearranging the position of the monitors using the Displays setting tool results in badly torn, messed up images. They resolve to something that looks almost usable a fraction of a second before the Does this look right? dialog gives up and reverts me to the original configuration, with my desktop backgrounds missing.
This is 2011, and multi-monitor configurations are not a novelty any more. In fact, they're the norm where I work, and I use external monitors with my laptops and netbooks all the time
Perhaps some of these issues are video driver problems, and Gnome 3 isn't to blame. But the problems with Gnome 3 are not limited to just multi-display configurations; for example: GDM's list of users does not scroll properly when the list is long (I went to file a bug on that one, but was disheartened searching through the 253 other open Fedora GDM bugs to see if it was already reported). If something goes wrong during the login process, a message appears telling you that something went wrong, but offering no way to find out what went wrong -- not even through a "Details..." button -- and the only action available to the user is to click a button marked "Ok" (I can't login? It's definitely not OK). The icons at the top of the screen respond to left- and right-click in the same way -- except for the iBus icon -- where's the consistency in that?