Wayland preview

Update: Daniel’s blog post here provides some more info, including how to install the technology preview on Raspbian today. And Pekka’s blog post here has some very detailed technical information on the implementation of the Weston backend.

If you’re familiar with the Raspberry Pi desktop experience, you’ll have noticed that windows on the desktop can be a bit slower to move around than you’re used to on your PC or laptop. This is because X, the windowing software (or composition protocol) that we use, is not optimised to use the graphics core of the BCM2835, the chip at the heart of the Raspberry Pi. All the work is done by the ARM processor instead, which slows things down and leaves the graphics core twiddling its thumbs. That graphics core is extremely powerful, so we’re working on putting it to good use to fix the issue.

We’ve made the decision to bypass X completely. Over the past few months we’ve been working with our friends at Collabora to implement the open-source Wayland composition protocol on top of the BCM2835 hardware video scaler (HVS). The HVS is a very powerful piece of hardware, with a scaling throughput of 500 megapixels per second and blending throughput of 1 gigapixel per second. It runs independently of the OpenGL ES hardware, so we can continue to render 3d graphics at the full, very fast rate, even while compositing.

Wayland composited desktop with XWayland and native applications.

In comparison to our current X11 desktop environment, Wayland frees the ARM from the burden of stitching together the top level of the composition hierarchy, and allows us to provide some neat features, including non-rectangular windows, fades for windows which don’t have input focus and an Exposé-like scaled window browser (the sort of thing that Mac users will be familiar with). Legacy X applications can still be supported using XWayland. Check out this video from Collabora to see these features in action, and to compare the current state of affairs with the Wayland future. Those non-rectangular shapes? They’re also windows.

We’re still working to improve performance and memory consumption, and don’t expect to be able to replace X11 as our default desktop environment until later in the year, but we will be including a technology preview in our next Raspbian release. Until then, this post on Collabora’s website gives some more background.

As with PyPy, the Raspberry Pi Foundation has funded this work on Wayland; it’s one of the ways we are trying to give back to the open-source community. Obviously, much of the work on this particular project is Raspberry Pi specific, but there’s a large portion of what’s being done, particularly around XWayland and some of the generic effects in Weston, that can be reused on many other platforms.

We’re looking forward to being able to push out the full release in the next few months. We hope you like the look of it!

15 comments Tags: car computer, derek knaggs, flamelily it 1 day ago by clive

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Raspbian running in the dash of a Ford Focus

Last century I spent weeks researching car computers. I wanted mp3s, videos and access to Notepad on the road. I wanted my car to respect and love me, just like KITT loved David. I wanted it to shout, “Right on tiger!” when I achieved an optimum MPG and to flash up encouraging messages like, “Hello Clive, might I say that you are driving very handsomely today” on a heads-up display.

Sadly it was never to happen. The reality was that you needed a PC the size of a coypu in the boot; an industrial 12/240v inverter; a 15″ CRT monitor strapped to your dash; and hawseholes in your bulkheads. And after a week of constant rebooting halfway through Captain Sensible’s Happy Talk, your hard drive failed because of the vibration and your battery discharged for good.  (I gave up and bought a 32Mb Diamond Rio and a hi-tech cassette adapter instead.)

Back in the 21st century, Derek Knaggs at Flamelily I.T has made the thing of my dreams: a low cost, low maintenance, general purpose car computer. There are other Pi-based car computers about but we especially liked this one because it’s simple, cheap and it looks like a factory fit. Very smart.

A quick swap of SDs and Raspbmc meets all of your multimedia needs

The Raspberry Pi is stored in the centre console and all wires routed underneath. Audio is fed through the aux socket of the car’s radio so no additional hardware is needed for this. A wifi dongle provides internet connectivity on the move via a mobile phone hotspot.

Neatly tucked away in the console — note the wifi dongle for internet on the move.

Full details including a shopping list are on Derek’s blog. I’m off to make one.

34 comments Tags: biodiversity, conservation, hackspaces, ocean monitoring, sharks, ZSL 2 days ago by clive

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Conservation, hackspaces and Raspberry Pis. And sharks. How could this not be the blog of the day? Gary Fletcher of ZSL sent us this report.
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Marine Conservation Camera

ZSL have developed low cost cameras to monitor marine biodiversity in large marine protected areas (MPAs) using the $35 Raspberry Pi single board computers and standard webcams and running opensource Motion tracking software. ZSL reached out to UK hackspaces to help design the cameras and achieved unprecedented economy and features.

 Why Raspberry Pi?

Traditionally it has been incredibly difficult to capture events underwater – all of the usual apparatus such as PIR/heat, infrared and ultrasonic sensors simply do not work underwater. The Raspberry Pi literally opened up a new door with its low power consumption and processing power. It allowed us to deploy a solution which really fits the bill and without it would have been very troublesome to achieve!

Hardware

Each camera was deployed on an anchored buoy. Mounted directly onto the buoys were two solar panels for charging two deep cycle 90Ah lead-acid gel batteries, the aerial, and a waterproof box containing the communications system. This was then connected to a 50m SWA cat-5 cable running down to the pressure vessel containing the camera itself.

Pressure Vessel

The cameras are designed to operate at depths between 20 and 50 meters. Rlab’s (Reading Hackspace) Ryan White suggested basing the design around a clear polycarbonate tube, with machined HDPE end caps secured by threaded rods and double o-rings. One end-cap had a threaded hole which SWA cat- 5 cable was run though, anchored to the inside and then potted. This cable runs the power and communications.

BuildBrighton’s Mike Poutney and Paul Strotten machined the endcaps on their lathe and offered some great technical advice which was very well received.

The outer pressure vessels easily survived a 100m pressure test in a hydrostatic chamber. It should go significantly deeper had the internal structure not failed at that point.

Internal Structure

Rlab’s (Reading Hackspace) Barnaby Shearer designed the internal support structure. This was laser cut from 3mm acrylic. The designs were done in 3D in OpenSCAD to check all the components fitted together, then projected into 2d for laser cutting. The acrylic was glued with tensol.

Cable waterproofing

The junction box was 3d printed and then sealed using potting compound and left to dry for some time also forming a mechanical join between the inside and the cable gland.

Communications

Attached to the buoy in a waterproof case was a Raspberry Pi to coordinate the communications. This had an Ethernet link to the Raspberry Pi in the pressure vessel. It also had a WiFi dongle running in access point mode to allow easy monitoring and reconfiguration form the research vessel. The Pi also has a serial connection to an Iridium satellite modem so it can stream pictures of the images captured.

The satellite image transfer software was specially developed by Cambridge Consultants and the equipment and satellite bandwidth for this trip was kindly sponsored by Iridium.

Electronics

Attached to the bottom Pi was an Eve board to provide the Pi a RTC and a temperature sensor. Also attached was Ciseco’s Humble Pi hosting an AVR and a mosfet to to turn the Pi off at night (and critically back on each morning). This Pi wake was developed by Miles and Matt from Ciseco, who make an amazing range of Raspberry Pi and microelectronics and are well worth a look – http://www.ciseco.co.uk/

These boards were slightly modified to handle a HackHD camera via the AVR so we could capture high definition footage as well as stills.

The boards were assembled at Nottingham Hackspace.

Camera

The camera used is the Microsoft LifeCam Cinema HD, a cost effective camera conforming to the UVC specification. The only gotcha proved to be that it seems to only respond to a few ‘magic’ exposure settings (5,10,20,39,78,156,312,625,1250,2500,5000,10000,20000), and you have to wait 100ms and reset the brightness after any exposure change.

Software

Rlab (Reading Hackspace), Gary Fletcher and Doug Snead provided a simple command line program to control the camera, and a slimmed down version of MJPEG-Streamer optimized for this camera and with some additional time stamping.

This stream then fed into Motion which starts saving the frames as JPEGs after it detects an event. The JPEGs are then rsynce’d up to the top Pi (backups are always a good thing). ImageMagick then thumbnails and montages the images for efficient sending over the (slow) satellite link.

Stereo Vision

The project did spur off onto some stereo vision development work with Doug Snead and Gary Fletcher but could not be completed in time for deployment. It was hoped that it would be possible to develop this solution as so it could automatically size the passing fish to add to our conservation data.

Image showing the accurate sizing of a fish tied to the ceiling flapping in front of an oscillating fan.

What did it Look Like

The deepest ever Pi?

At 50 meters deep – could this be the deepest Pi to date?

Where was it Deployed?

The system was tested at ZSL in London Zoo behind the scenes and then went onto to open Ocean tests in the largest marine protected area in the world, the Chagos Archipelago.

Gary Fletcher and Barnaby Shearer test the camera at ZSL London Zoo, behind the scenes

Results

Well as you can see the results speak for itself, but there is still quite a lot of development work to do but once these sentient units are complete, it will offer a low-cost monitoring system that, when deployed as a network, will greatly expand ocean areas that can be observed.

For those that would like a little further reading on the actual deployment, please have a look here on the Chagos Trust website http://chagos-trust.org/projects/latest/feb-2013-expedition/battling-heat

Acknowledgements

Gary Fletcher, Barnaby Shearer, Ryan White, Richard Ibbotson, Doug Snead, Paul Strotten, Mike Pountney, Miles Hodkinson, Matt Lloyd, Adam Markwell, Gary Fletcher Senior, Anna Fletcher, Charles Turner, Marty Morriss, David Curnick, Matthew Gollock, Heather Koldewey, Alasdair Davies, Charles and Anne Shepard, Yannick Mandarin, Ronan Roche, Reece Pitts, Richard Traherne, Marion Campbell, Jonathan Pallant, Ant Skelton.

3 comments Tags: Alan O'Donohoe, national STEM centre, Raspberry Jam, york 4 days ago by clive

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A post from Mr Raspberry Jam himself, Alan O’Donohoe.  This one promises to huge and fabulous, and the National STEM Centre is an outstanding venue. I am strangley drawn to joining the trans-Pennine convoy from Preston.

“You may have seen that we are holding a big Raspberry Jam in York on Saturday 8th June, 3 weeks today. Tickets are available here.

I’ve been working with the folks at the National STEM Centre there to help establish a presence in Yorkshire for Raspberry Jams. There are a lot of people in Yorkshire who have bought Raspberry Pi computers or who have not bought one but are interested in discovering just what you can do with them and this event is to give them a taste of the Raspberry Pi.

This event is going to be much larger than our regular Raspberry Jam events and we know that people  are travelling from far across the UK to attend. I will be travelling in a convoy of cars from Preston bringing old friends and new friends on the journey across the Pennines. Road-trips like these add an enormous amount to the whole experience.

Our busy programme of talks, demonstrations, stalls and hands-on classes is now filling up. We are delighted to have Pete Lomas of the Raspberry Pi foundation speaking and leading a workshop, he is the gentleman who actually designed the Raspberry Pi. We also have Amy Mather the 14 year old who learnt how to program Conway’s Game of Life on the Raspberry Pi, her film on YouTube has attracted over 27000 views.

If you look at our programme , you will see that we have a wide range of classes from how to switch on a Raspberry Pi to building weather stations, interfacing, networking, robotics, game making for all the family and programming in Python. David Whale will be running a workshop on how you can set up an after school Raspberry Pi club.

‘import random’, the start of great game! A Raspberry Jam programming class.

We hope to attract a diverse range of people to attend this family friendly event:

• Teachers - who want to know if the Raspberry Pi is something they can use to support the teaching of Computing
• Families - who together want to develop and nurture an interest in technology and computing
• Hobbyists - who want to meet other people with a desire to share what they have been doing with their Raspberry Pi
• Anyone - who has an interest in the Raspberry Pi at any level.

If you have never been to the National STEM centre before, this is a fantastic opportunity to come and discover what is there http://www.nationalstemcentre.org.uk/