What stereo equipment out there is computer controlable? I'm working on ripping all my CDs to MP3s, and wish to setup a music server as part of my stereo stack. I'd like to be able to control the amplifier directly by the computer. Stuff like turning it on and off, setting volume, switching between various inputs, etc. I know it's possible to use an IR transmitter to control an amp that has a remote, but I'd like to also be able to get feadback from the amp as well as more positive control that a direct link would provide. Price is a relative issue, but if I need to I can easily strech my budget higher so I'm not setting limits. The final thing is I wish to do this under Linux if at all possible, but if that isn't possible I might be persuaded to use Windows or some other OS.
For using it for astro photography you will need to be able to control the shutter speed. Many of the cheeper digital camers don't allow this. I don't know if yours allows shutter speed control or not. I own a Nikon 990 which allown me to do long exposures, up to 60 seconds if I hold the shutter button down. Unfortunatly it starts to show significant dark current problem on any photograph over 10 seconds long. It even shows some on 8 second shots. Another problem you will run into is the CCD chip in the camera has a color mask built in. This gives it color ability, but it also reduces the amount of light going to each resolveable pixel, typically 1/3rd to 1/4th. This means image times are atleast 3 to 4 times longer than with a BW CCD for a color shot. It also causes color effects as the image is sampled at different spots for each color. One can't get by the time issue for color astro work. However one can get around the color sampling at differnt spots. Astronomers use BW CCD cameras and color wheels, then take one shot each for red, gree, and blue. For good measure most astro photographers will also take a straight BW shot to. Another thing is the resolution the image's pizels are sampled at. Most consumer digital camers use 8 to 12 bit analog to digital converters in them. For astronomy you need as many bits as possible Many astro cameras are now at 16 bits.
There are cameras specially made for astronomy. Unfortunatly their prices are astronimical in relation to regular consumer cameras. SBIG is a major maker of astro camers for amatures and profesionals. It's a volume issue, plus these cameras have special coolers to help control and reduce dark current. The increased sampling resolution also helps jack the price up.
You can do some limited astro work with consumer digital cameras. It's mainly limited to very bright objects like the moon and sun. Note if photographing the sun, only use proper sun filters made for looking at the sun. Any telescope or camera lense can and likely will intensify the light into dangerous eye dammaging levels.
I'm a member of the Twin Cities Robotics Group. We deal with electronics all the time, and boy do we have fun doing it. The level we are playing at ranges from simple to complex. I personally am making an ISA bus board to do motor control with. It's a combination of both digital and analog circuitry. It's beyond the beginner in that it's a combination of analog and digital circutry as well as both VHDL and Linux device driver programming. Another in the group is doing a laser range finder that is even more complex. We're both using complex programible logic devices (CPLD**) at the cores of your designs.
Robotics is a way to get people doing electronics in a fun way. Many simple robot designs don't even need a CPU, just carefull tuning. Take a look at BEAM robotics (Solarbotics has some BEAM type kits). They are simple brainless robots that move around based on simple hardware programming. Learning what it takes to make these tick would help tremendously at teaching electronics. BEAM style robots rely on feadback loop electronics to operate. LEGO Mindstorms is another way into robotics. After one has mastered what the LEGO parts can do, one can start building your own electronics hardware interfaces.
** We're using Xilinx's WebPack CPLD programing tools. Other companies also have tools available for free or cheep.
Considering I use an OpenBSD box as my prmary web server and it's been up for ages without being hacked. I'd say OpenBSD is a good choice. Remember, anything truly sensitive in the DOD isn't on the publicly linked nets. They are even partitioning more and more computer systems into totally private networks. If the nets aren't linked, then data can flow without direct human intervention on site.
I think both the Justice department and the NSA have both said they use OpenBSD. I'm a little less certin on the NSA having said so. I do remember a story about the Justice Department using OpenBSD for it's sensitive data.
Kinda reminds me of my first astronomy class. I hadn't even made it to my freshman year of high school and I had 4 credits of Astronomy from the local community college.
Many people have given good advice above. I'll mainly just second their comments. The order I'd proceed in is.
First item, a good beginners star atlas.
Second item, warm clothing.
Third item, many nights in the country just learning the stars and constelations.
After that go and get a good pair of binoculars or a good telescope.
Last, but not least. As your doughter is so young, you will need to be there as a source of infromation. You'll need to learn alot to help guide her in the early years.
Now for some Links. The first two have good beginners information. Some of the links below may be dead. I just quick cut and pasted them from the astronomy section of my Interesting Places page.
The Telescope Shoppe (www.telescopeshop.com),
3402 Federal Dr., Eagan, MN, 651-688-7335. Yes this is a local Twin
Cities telescope shop. They have a map on their site showing where
they are. They are tucked in the lower level along the side of the
strip mall they are in. The store is small and easy to miss.
If your at the corner of Yankee Doodle RD and Federal Dr., park in the
lot to the south east. They are a short stones throw from the intersection.
Potentially Hazardous Asteroids (cfa-www.harvard.edu/iau/lists/PHACloseApp.html).& nbsp;
Of particular interest to me are LB16 and AN10 which will pass at a distance
closer than the moon's orbit. LB16 currently only has one opposition
charted so it's predicted orbit will likely change as new data comes in.
It's expected to swing by in 2004. In 2027 AN10 will visit earth.
It's orbit is calculated with three oppositions meaning it't much more
likely to really showup ontime and in place. With further data LB16
could either get closer or farther away. When AN10's orbit was first
predicted (only one opposition at the time) it's error envelope included
earth. With further data it was found to just pass within the moon's
orbit and miss the earth.
Forthcoming Close Approaches To The Earth (cfa-www.harvard.edu/iau/lists/CloseApp.html).&nbs p;
This is the document to look at when you want to know who will visit next
and how far away. It has all close approaches to 0.2 AU away from
earth or within 20% of the distance of between the sun and earth.
On Sep 19th, 2000 we will have a visiter at 0.0477 AU and on Oct 31st anotehr
one will pass at 0.07386 AU. LB16 and AN10 are expected to pass at
around 0.25% of the distance between the sun and earth.
Mars Orbiter Laser Altimeter (MOLA) (ltpwww.gsfc.nasa.gov/tharsis/mola.html).
There are full data on the shape of Mars including 1 degree and.5 degree
elevation data sets.
Why bother with a laser. They are a pain to drive. Use a high intensity LED and lenses. You don't need precision lenses either. Cheap plastic ones will do. Just point the high intensity LED in the direction of the receiver. Use the lense to focus the light from the LED onto the photo transistor. A black disk behind your LED can help improve the signal to noise ratio. Especially if it is large enough to cover the hole area focused on to the phototransistor. The longer the focal lenght of the lense, the smaller the area see at the LED end.
The database seems to have got corrupted, and various articles are only appearing in the sections, rather than as part of the main story flow. You can't even get to this one (or the NT Hosting Trollfest) via the Previous and Next article links below the articles.
You're right though, this IS important news!
Not at all. Some topics are not considered important enought to get front page billing. This one didn't make the grade.
I keep an old beatup laptop with me all the time cos it has Linux+SSH on it. I can hookup from almost anywhere I can find a phone or network port. I don't have a cellphone because I don't want to spend the $$$ on it out of my pocket. If a place I'm working wants me to have that level of connectivity they can pay for it.
Wireless has it's place in a university. It's for wearable and laptop conectivity, nothing else. Do all the rest with cat5 and fiber. Fiber between the network wireing closets, within and between buildings. Cat5 every where else. Any stationary computing device should be hooked up via cat5. Mobile devices like laptops can use wireless to remain connected. I'd have the hole campus covered by wireless for the laptops, but would not do any of the campus backbone in wireless if at all possible. Wireless can also be used to an extent for hard to wire buildings, but student labor is cheep.
Sounds like DV format or MJPEG. I'd say at a 5-1 compression ratio too. DV is the format most of the high end consumer digital video recorders use. Not quite broadcast quality, but good enough nobody will notice. A 3.3-1 compression ratio is generally considered broadcast quality.
Choose your server hardware carefully. Many companies are now offering access to the PC keyboard and BIOS via a second NIC with dedicated hardware. A means to power cycle the machine also helps.
Design your system for redundancy. Possibly add a spare system or two with all software, data loaded. This way it can take over the work of a failed system. This spare system could also be loaded with a couple of huge drives to be a backup host for the other servers. One site I know of has a management system that also provides backup service, and can be used as a spare server too. They have a firewall/load ballancer, 5 web servers, 2 database servers, and the management system in 10U of space. The tenth slot is the keyboard/flatpannel display tray for the management system. All the systems are Linux based with serial consoles. The management system can also power cycle any of the other systems and it's self.
Actually I'd recomend getting a few laptops. One main one and some spares. Place the spares in a waterproof box and only pull them out when needed. For the main one, have a water proof box for it to live in when not in use.
Seeing that it will be subjected to a marine environment I sugest going through each laptop and conformal coating all the circuit boards.
Have you looked at purpose built computers for the marine market? They have to have come along way sense I last looked at them in the late 80's. Also as others have said, look at industrial. Many fine systems, many portable and battery operated. Also look at what has been designed for inventory control. Some of them are waterproof.
I'm a similar boat, but I have a different end use. I'm looking to build an instument that will be a remotely situated net appliance. It also needs to be waterproof, cold proof, low-power, but dosen't need a user interface. There are many low power computer solutions out there. It all depends on what you are willing to pay and how much assembly you wish to do.
A system I'm looking at (DIMM-PC from JUMPtec) needs case, keyboard/mouse, and display to be provided by the integrator (me). It is very low power, has a LCD interface for driving a LDC display, has onboard FLASH disk (32MBytes), and is expandable. The reason I'm looking at it is it uses 2 watts for it's core, and with all expected parts added in I'll be under 5 watts total. You would want to add in a LCD, but I can see it staying under 10 watts total.
Just what is the size of current backup tape systems that one might use to archive this puppy.
For home systems the new large HDs are making a backup nightmare. Right now I backup from one system to another, and cut CDs of new stuff, but it's difficult to keep up with my digital camera's output.
OpenBSD may not magically fix all holes, but it does provide a very nice secure starting point. Even though OpenBSD is very secure right out of the box I still wouldn't drop it directly on the net. I'd have a firewall between it and the net. Both my OpenBSD boxes that are on the net live behind a firewall. I wouldn't do it any other way.
Not a good idea if you are using a cable modem, DSL, dialup, or other unreliable connection. If your DNS is up but your mail exchanger is down, the remote (sending) host will queue your mail but if you nameserver is down, it will most likely be bounced immediately.
It actually can work quite fine. I have a DSL line, my own DNS server and a few other services running. My ISP VISI provides secondary name services for me.
It's not just major cities... Any new traffic light seams to be a prime candidate for LEDs. Something about maintence costs alown call for the switch. At a cost of about $250 to change a traffic light, a light that lasts 20 times longer quickly pays for it's self even if it is a $500 light. To make matters worse, the worst LED traffic lights use only 18% of the energy of a regular traffic light. One city alown was figuring they would save $250,000 a year on electricity once fully converted to LED traffic lights. The current problem is production numbers. Not enough are being produced so they can't go hog wild replacing them. Some still need to get the old lights.
I purchased a bunch of CREE full color LEDs from DigiKey a few years ago for only $7ish each. Cool things. To bad they don't sell them anymore. I'd like to get some more, but I'd prefer surface mount instead of pins.
"you're basically exchanging loads of spam from them reselling your e-mail address for the $40 rebate."
Kinda why I now have grumpy@nerdvest.com. I got tired of spam from retailers I've bought from. They all now get the grumpy address. It's my standard purchace item address.
Not to use the office internet connection for personal use. Except on breaks.
Not even breaks are safe.
To keep the stuff I really want to keep private private. I use my palm pilot, modem and TGPostman over a VPN link to home to get and send my email. Sure thay can tap the phone, but all they will get is encrypted garbage.
Sorry, they are to light to work as paperweights. After you grab the TV and plunk it down on top of one it may be able to keep papers from flying away, but then the TV may crush it.
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What stereo equipment out there is computer controlable? I'm working on ripping all my CDs to MP3s, and wish to setup a music server as part of my stereo stack. I'd like to be able to control the amplifier directly by the computer. Stuff like turning it on and off, setting volume, switching between various inputs, etc. I know it's possible to use an IR transmitter to control an amp that has a remote, but I'd like to also be able to get feadback from the amp as well as more positive control that a direct link would provide. Price is a relative issue, but if I need to I can easily strech my budget higher so I'm not setting limits. The final thing is I wish to do this under Linux if at all possible, but if that isn't possible I might be persuaded to use Windows or some other OS.
For using it for astro photography you will need to be able to control the shutter speed. Many of the cheeper digital camers don't allow this. I don't know if yours allows shutter speed control or not. I own a Nikon 990 which allown me to do long exposures, up to 60 seconds if I hold the shutter button down. Unfortunatly it starts to show significant dark current problem on any photograph over 10 seconds long. It even shows some on 8 second shots. Another problem you will run into is the CCD chip in the camera has a color mask built in. This gives it color ability, but it also reduces the amount of light going to each resolveable pixel, typically 1/3rd to 1/4th. This means image times are atleast 3 to 4 times longer than with a BW CCD for a color shot. It also causes color effects as the image is sampled at different spots for each color. One can't get by the time issue for color astro work. However one can get around the color sampling at differnt spots. Astronomers use BW CCD cameras and color wheels, then take one shot each for red, gree, and blue. For good measure most astro photographers will also take a straight BW shot to. Another thing is the resolution the image's pizels are sampled at. Most consumer digital camers use 8 to 12 bit analog to digital converters in them. For astronomy you need as many bits as possible Many astro cameras are now at 16 bits.
There are cameras specially made for astronomy. Unfortunatly their prices are astronimical in relation to regular consumer cameras. SBIG is a major maker of astro camers for amatures and profesionals. It's a volume issue, plus these cameras have special coolers to help control and reduce dark current. The increased sampling resolution also helps jack the price up.
You can do some limited astro work with consumer digital cameras. It's mainly limited to very bright objects like the moon and sun. Note if photographing the sun, only use proper sun filters made for looking at the sun. Any telescope or camera lense can and likely will intensify the light into dangerous eye dammaging levels.
Robotics is a way to get people doing electronics in a fun way. Many simple robot designs don't even need a CPU, just carefull tuning. Take a look at BEAM robotics (Solarbotics has some BEAM type kits). They are simple brainless robots that move around based on simple hardware programming. Learning what it takes to make these tick would help tremendously at teaching electronics. BEAM style robots rely on feadback loop electronics to operate. LEGO Mindstorms is another way into robotics. After one has mastered what the LEGO parts can do, one can start building your own electronics hardware interfaces.
** We're using Xilinx's WebPack CPLD programing tools. Other companies also have tools available for free or cheep.
Considering I use an OpenBSD box as my prmary web server and it's been up for ages without being hacked. I'd say OpenBSD is a good choice. Remember, anything truly sensitive in the DOD isn't on the publicly linked nets. They are even partitioning more and more computer systems into totally private networks. If the nets aren't linked, then data can flow without direct human intervention on site.
I think both the Justice department and the NSA have both said they use OpenBSD. I'm a little less certin on the NSA having said so. I do remember a story about the Justice Department using OpenBSD for it's sensitive data.
Kinda reminds me of my first astronomy class. I hadn't even made it to my freshman year of high school and I had 4 credits of Astronomy from the local community college.
Many people have given good advice above. I'll mainly just second their comments. The order I'd proceed in is.
First item, a good beginners star atlas.
Second item, warm clothing.
Third item, many nights in the country just learning the stars and constelations.
After that go and get a good pair of binoculars or a good telescope.
Last, but not least. As your doughter is so young, you will need to be there as a source of infromation. You'll need to learn alot to help guide her in the early years.
Now for some Links. The first two have good beginners information. Some of the links below may be dead. I just quick cut and pasted them from the astronomy section of my Interesting Places page.
Why bother with a laser. They are a pain to drive. Use a high intensity LED and lenses. You don't need precision lenses either. Cheap plastic ones will do. Just point the high intensity LED in the direction of the receiver. Use the lense to focus the light from the LED onto the photo transistor. A black disk behind your LED can help improve the signal to noise ratio. Especially if it is large enough to cover the hole area focused on to the phototransistor. The longer the focal lenght of the lense, the smaller the area see at the LED end.
The database seems to have got corrupted, and various articles are only appearing in the sections, rather than as part of the main story flow. You can't even get to this one (or the NT Hosting Trollfest) via the Previous and Next article links below the articles.
You're right though, this IS important news!
Not at all. Some topics are not considered important enought to get front page billing. This one didn't make the grade.
It may be funny, but it works.
I keep an old beatup laptop with me all the time cos it has Linux+SSH on it. I can hookup from almost anywhere I can find a phone or network port. I don't have a cellphone because I don't want to spend the $$$ on it out of my pocket. If a place I'm working wants me to have that level of connectivity they can pay for it.
Wireless has it's place in a university. It's for wearable and laptop conectivity, nothing else. Do all the rest with cat5 and fiber. Fiber between the network wireing closets, within and between buildings. Cat5 every where else. Any stationary computing device should be hooked up via cat5. Mobile devices like laptops can use wireless to remain connected. I'd have the hole campus covered by wireless for the laptops, but would not do any of the campus backbone in wireless if at all possible. Wireless can also be used to an extent for hard to wire buildings, but student labor is cheep.
Personally I thought an "advanced face-obscuration technology" was makeup. A low tech one is a ski mask.
Sounds like DV format or MJPEG. I'd say at a 5-1 compression ratio too. DV is the format most of the high end consumer digital video recorders use. Not quite broadcast quality, but good enough nobody will notice. A 3.3-1 compression ratio is generally considered broadcast quality.
That's what background jobs are for...
I'm currently copying 20G of data from one disk to another so I can update the filesystem on the source disk.
Choose your server hardware carefully. Many companies are now offering access to the PC keyboard and BIOS via a second NIC with dedicated hardware. A means to power cycle the machine also helps.
Design your system for redundancy. Possibly add a spare system or two with all software, data loaded. This way it can take over the work of a failed system. This spare system could also be loaded with a couple of huge drives to be a backup host for the other servers. One site I know of has a management system that also provides backup service, and can be used as a spare server too. They have a firewall/load ballancer, 5 web servers, 2 database servers, and the management system in 10U of space. The tenth slot is the keyboard/flatpannel display tray for the management system. All the systems are Linux based with serial consoles. The management system can also power cycle any of the other systems and it's self.
Actually I'd recomend getting a few laptops. One main one and some spares. Place the spares in a waterproof box and only pull them out when needed. For the main one, have a water proof box for it to live in when not in use.
Seeing that it will be subjected to a marine environment I sugest going through each laptop and conformal coating all the circuit boards.
Have you looked at purpose built computers for the marine market? They have to have come along way sense I last looked at them in the late 80's. Also as others have said, look at industrial. Many fine systems, many portable and battery operated. Also look at what has been designed for inventory control. Some of them are waterproof.
I'm a similar boat, but I have a different end use. I'm looking to build an instument that will be a remotely situated net appliance. It also needs to be waterproof, cold proof, low-power, but dosen't need a user interface. There are many low power computer solutions out there. It all depends on what you are willing to pay and how much assembly you wish to do.
A system I'm looking at (DIMM-PC from JUMPtec) needs case, keyboard/mouse, and display to be provided by the integrator (me). It is very low power, has a LCD interface for driving a LDC display, has onboard FLASH disk (32MBytes), and is expandable. The reason I'm looking at it is it uses 2 watts for it's core, and with all expected parts added in I'll be under 5 watts total. You would want to add in a LCD, but I can see it staying under 10 watts total.
And what am I suposed to back it up to?
Just what is the size of current backup tape systems that one might use to archive this puppy.
For home systems the new large HDs are making a backup nightmare. Right now I backup from one system to another, and cut CDs of new stuff, but it's difficult to keep up with my digital camera's output.
Buh!, Why not?
Why not make a WinCE app that goes and loads Linux off the CF card, and in the process takes full controll of the device? What's stopping that?
OpenBSD may not magically fix all holes, but it does provide a very nice secure starting point. Even though OpenBSD is very secure right out of the box I still wouldn't drop it directly on the net. I'd have a firewall between it and the net. Both my OpenBSD boxes that are on the net live behind a firewall. I wouldn't do it any other way.
It actually can work quite fine. I have a DSL line, my own DNS server and a few other services running. My ISP VISI provides secondary name services for me.
It's not just major cities... Any new traffic light seams to be a prime candidate for LEDs. Something about maintence costs alown call for the switch. At a cost of about $250 to change a traffic light, a light that lasts 20 times longer quickly pays for it's self even if it is a $500 light. To make matters worse, the worst LED traffic lights use only 18% of the energy of a regular traffic light. One city alown was figuring they would save $250,000 a year on electricity once fully converted to LED traffic lights. The current problem is production numbers. Not enough are being produced so they can't go hog wild replacing them. Some still need to get the old lights.
I purchased a bunch of CREE full color LEDs from DigiKey a few years ago for only $7ish each. Cool things. To bad they don't sell them anymore. I'd like to get some more, but I'd prefer surface mount instead of pins.
Kinda why I now have grumpy@nerdvest.com. I got tired of spam from retailers I've bought from. They all now get the grumpy address. It's my standard purchace item address.
Not even breaks are safe.
To keep the stuff I really want to keep private private. I use my palm pilot, modem and TGPostman over a VPN link to home to get and send my email. Sure thay can tap the phone, but all they will get is encrypted garbage.
Sorry, they are to light to work as paperweights. After you grab the TV and plunk it down on top of one it may be able to keep papers from flying away, but then the TV may crush it.