www.linuxastronomy.org

Los Angeles Convention Center. February 12 - 13 2005

[Show page] [Web camera images]

Why did you have mostly outdated hardware on the booth ? We try to use recycled computers, when ever we can. It also show younger people that using an "older computer", does not mean it "does not work anymore", but it can still accomplish requested tasks, without any flaw. It teach also, the value of things. It show well the linux operating system can run on older hardware. What was the windowmanager displayed on the booth's computer ? The windowmanager (graphical user interface) we used for the show was "Windowmaker" on every machine. It is frugal in cpu resources, making it a good choice for older machines. It is simple to use and we like it. Others windowmanagers such as "Afterstep", "fvwm", "icewm", "blackbox", "fluxbox", etc. would have work as well. What was special about the big picture in the snow with the linuxastronomy banner ? Was it really from the South Pole ? As mentioned at the show, the image displayed, was from the " South Pole" indeed. The image was taken by a friend, working at a European base, managed by an Italian and French organization. It is located in Antartica, close to an area called "Dome C". The station is called "Concordia". What is the link between the South Pole and linux or/and astronomy ? Our goal was to show you, we are a virtual group, from anywehere on the planet and perhaps beyond... We have similar goals and try to make life better one step at a time. We cooperate by exchanging ideas as well as building projects together. When possible, we work with younger people, first to keep them busy, also in the hope they will learn something useful for their life later. Why did you present a seismometer ? The seismometer or seismograph was a great coopeation project between a few people located in different areas. It is also an object not many people have seen, especially not a home made seismometer. What does it have to do with Astronomy ? It can help us find out the quality of a location, by analysing the ground motions. It can be useful to find out if something happened when we get a blurry picture from the telescope. It can help us to find out if the telescope has a mechanical problem. Can you explain how did you do to put on the linuxastronomy.org website, the temperature, volt, seismo data and web camera images, gathered on the showfloor ? The temperature data where gathered using a temperature probe, which is a resistance that vary with the temperature. The probe was connected to an ohm meter (multimeter). The meter is equipped with a serial interface (RS-232c) Which connected it to a relatively old computer tower (P-I, 90 MHz, 128 MB RAM) (Pentium 1). The computer sent the temperature data every five minutes, to a server (P-II, 266 MHz, 128 MB RAM) located in the booth. The data comming from the seismometer or seismograph where gathered every 1.5 seconds, from the voltage generated in the seismometer coil by two test wires connected to a volt meter (multimeter). The meter was equipped with a serial port as well (RS-232c), which connected it to a laptop computer (P-II, 266 MHz, 128 MB RAM) (Pentium 2). The laptop computer sent the seismometer data (voltage) every 2 minutes, to a server (P-II, 266 MHz, 128 MB RAM) located in the booth. The volt data was gathered every 1.5 seconds using two test wires plugged into an outlet. The test wires were connected to a volt meter (multimeter). The meter is equipped with a serial interface (RS-232c), which was connected to the main (booth) server (P-II, 266 MHz, 128 MB RAM). The web camera data (images), where gathered every 15 seconds by a USB camera (Logitech QuickCam 4000). The images where sent through the USB port, to the main (booth) server (P-II, 266 MHz, 128 MB RAM). The main (booth) server (P-II, 266 MHz, 128 MB RAM) then sent regularly, all the collected data, through the internet to a server hosting our website. Why the Amps data do not show up on the linuxastronomy.org website ? To measure AC Amps we needed a "clamp meter" with serial ports, item we did not have, or a to cut a line and safely connect it to the amp meter. It is for safety reason, we decided not to connect the amp meter we had. What application did you use to display gathered data on each screen ? The temperature, volt and seismometer (seismograph) data where displayed using a program written in Python, called "pyDmm", developed by linuxastronomy volunteers. Why did not you display a telescope at this year show ? Because we had one last year. Next question... Ok, we try to show different realizations each year. We display the realizations we have done that are ready or ready enough to be at a show. Hopefully next show, we will have done more work on the newer telescope project and be able to bring it at the show. There is also a space factor, our booth was pretty crowded. You guys are making and presenting "cool stuff", can we find some on your site ? On the bottom of the previous page (SCALE 2005 page) is a selection of projects we have done. They are not all completed yet as of this writing, meanwhile you will find a description of "cool" projects.

older pc windowmaker (external link) afterstep (external link) South Pole (external link) Seismometer SCALE 2005 pyDmm Cool projects samples

Equipment used at the Southern California Linux Expo 2005.
Temperature measure The picture show the equipment used to measure the temperature at the show. The tower computer is an older P-1, 90 MHz (Pentium 1) with 128 MB RAM. A measure has been taken every 5 minutes. Once each reading has been transfered to the main server (on the booth), it was send to a server hosting our website. The temperature recording started on Friday evening around 19:30 PST and recorded up to Sunday afternoon around 14:30 PST (Pacific Standard Time) non stop. The meter is a Metex Me-11, or Radio Shack 22-805. They are a lot of meters that are identical, they just have a different name plate, or color. It is an inexpensive meter, in our area. The temperature reading line, start low then goes up. The reason is, Friday at setup time, most of the door were open, air was circulating through the building. Later, in the evening, the doors have been shut, the air became progressively stabilized.
Web camera. The web camera we used is a Logitech QuickCam pro 4000, others possible choices exist. A picture has been taken every 15 seconds from Friday around 17:00 PST up to Sunday around 17:00 PST. The camera sent images using the USB port to the main (booth) server (the camera had direct connection with it). Only images with enough changes from the previous one were kept. The program "webcam" (which seems to be a daemon) was comparing between the previous and the current image. If they were enough changes in the pixels, the image was saved. The images were then scaled 2 times, given a name using the date and time, each image was saved in a directory, then renamed to a generic name to be sent to the main server.

Seismometer. A seismometer reading has been done every 1.5 seconds. This is clearly not enough for a real application, but fine in our case, that just try to present a "proof of concept" at the show. The seismometer is a homemade creation, it evolve. As an example, it is improved from the last show it has been displayed (LinuxWorld Expo San Francisco, in August 2004). It will still be improved to make it slightly better each time. It has recorded several earthquake that has been displayed on USGS web pages. When a magnet move inside the solenoid, it generate some electric current. The solenoid (coil) has 30'000 spires of very thin wire, it is sensitive enough to pickup micro vibrations generated by ground motion even far away (several 1'000 miles). The signal is read by the voltmeter, which send it to a laptop computer using the serial port (RS-232c) also. The laptop transfert the data to the main (booth) server.

Main server on the booth. The main (booth) server sent the images, temperature, volt, seismo data about every 2 - 5 minutes, through the internet, to the server that host our web site. The reason it was every 2 - 5 minutes was, we did some demonstrations and changed the time value in this range. All the data transfert between machines have been done using shell scripts.

Hint to help computers displacement. To facilitate the transportation of heavy computers (to carry computers from a parking lot to another floor between a few rooms, has a tendancy to become quickly heavy), some little ruber wheels have been installed under them. They are casters used for furnitures, they seem to be better than the smaller ones that sometimes come with computer cases.