QuadraSpace

As posted last year, we decided to use a low-power consumption machine as the very first QuadraSpace server. The goal was to embrace the green computing philosophy, that is trying to limit the energy needed to run the IT infrastructure of the project. Low-power consumption on the server means also low-power consumption on cooling systems and, at the end, low-noise pollution.

Since last January, we were experiencing strange unexpected power loss on the server. We thought it was caused by a recent kernel upgrade of the Ubuntu Server 9.04 distribution. Some posts in dedicated forums stated that there could be issues with the ACPI support on ION-based boards (ION is NVIDIA chipset that runs on the Acer Aspire Revo R3600).

After weeks of investigation, we found that the issue was caused by the thermal protection of the CPU. In certain condition (but we were not able to determine what was the actual reason), the operating system powered off the server to protect the hardware. However, there was not relation between CPU load and unexpected power off.

We moved from software to hardware. Apparently there were no issue with the CPU fan. Apparently. We powered off the server for about one hour, just to replace some cables, then the server was powered up again. After a while, the was a strange noise coming from the server: some “crick”, “crack” on the plastic covers. In less than a quarter the server case was very hot and the fan was not working. After a while, the fan started to rotate very slowly, but the board was so hot that Ubuntu powered off the system.

We opened the case and we discovered that the fan was not working properly.

The REVO opened

After a power cycle, the fan may rotate very slowly or even be completely blocked. However, at the very start of the system (where the fan is powered-on for a bit, without any speed control), it always rotated at maximum speed. We deduced that there was an issue with the fan speed control.

The fan removed from the heatsink

Therefore, we decided to completely exclude the fan control (which is performed using a PWM signal on the blue cable) and to leave it to run at maximum speed.

The BLUE cable has been cut: no power speed control will stop the fan!

The QuadraSpace server is now much more noisy, but no more unexpected power-off have been experienced.

Keep sensing, now…

QuadraSpace Team is happy to announce the collaboration with Sensaris (http://www.sensaris.com). First result of this collaboration is the Senslink application for Android, which connects to Senspod sensors using Bluetooth. Next step will be integrating the Senspod in the QuadraSpace architecture.

We are very happy to publish the XML Schemas of the QuadraSpace protocol. The Schemas, kindly written by Antonio Pintus, are being used to generate stubs on the QuadraServer implementation and they can be used by anyone that wants to implent his own QuadraSpace-compliant server or client.

XML Schemas are available on the Specification page.

Just a photo, stay tuned for details…

QuadraSpace first sensor prototype

QuadraSpace aims to be a “green computing project”: we will try to use low consumption hardware on both servers and motes and to limit electromagnetic pollution when using wireless connections. The first step to reach this goal is to (try to) use low-power computers for the backend and to prefer motes powered by renewable energy whenever possible.

First action on backend-side is the adoption of a Acer Aspire Revo R3600, an “eco-computer” based on Intel’s Atom 230 processor and NVIDIA ION platform, as first QuadraServer node.

This small computer runs with a 65W power supply for its internal components (everything but an optical drive); in current QuadraServer setup there are also two external hard drives used respectively for the RAID-ed data storage and backup for internal system disk. Total power consuption will be about 100W. Having QuadraServer always-on 365/24/7 requires 0.1 * 24 * 365 = 876KWh, that produce about 470 kg of CO2 (just for reference, a typical SUV equipped with a 3 litres engine, produces the same amount of CO2 to run less than 2000km!).

Next week we will setup the server and we hope to have the QuadraServer instance up&running in a couple of weeks.

Stay tuned!

First QuadraSpace mobile mote has appeared on a HTC Magic Androd phone:

Stay tuned

Fourth draft of the QuadraSpace protocol has just been published!

First of all, we’d like to thank all friends that have sent their comments about previous drafts of QuadraSpace: your help has been valuable for improving the protocol, include features you expected and to find pitfalls in the specifications. We have carefully taken into account some considerations about REST approach (thank you Emanuele), and we finally changed QuadraSpace to support all main HTTP methods (GET/POST/PUT/DELETE) but to guarantee access to the backend also for those devices (Java ME CLDC/MIDP in primis) that lack full HTTP client in their standard library. We will give ore details about that in upcoming articles. Finally, each event has a type, that can be “sample” or “heartbeat”. “Sample” is the event as it was originally described (a notification of some data read by a sensor). “heartbeat” is a “still-alive” message sent by the mote to notify that it is fully operative (thank you Dadaista for reminder!).

The first draft was 47 slides long: the new 4th draft nearly doubles that size (84 slides)! QuadraGrowing!

Find it at:

http://quadraspace.googlegroups.com/web/qs_protocol_DRAFT4.pdf

or browse it on this web site:

Third draft of the QuadraSpace protocol has just been published!

Find it at:

http://quadraspace.googlegroups.com/web/qs_protocol_DRAFT3.pdf

Second DRAFT of the QuadraSpace protocol has just been published.

QuadraSpace is an effort for creating and delivering an open source protocol and services for sensor networks.

We have published the first DRAFT of the protocol on 2009/04/21 (available in PDF at GoogleGroups). Second DRAFT will be published shortly.