Magnets allowed?¿?

[josh_johnson]

Originally Posted by Rickertsen2

Even with VERY powerful magnets, it would be VERY difficult to induce enough voltage in anything to cause interference. It would take ALOT of gauss. and remember 1/x^2 rule. Anybody care to work out some Emag? Maxwell's equations Mmmmm...

I'm not sure about the exact amount induced, but I did have problems with using my cell phone when i got within about 6 in. to a foot of a magnet that came from an old hard drive. It did not cause problems with interference, but caused my phone to reset itself.

You probably wouldn't interfere with another robot from several feet away, but depending on the location of the magnet, it might cause problems when the robots are very close to each other.

[DKolberg]

Originally Posted by Rickertsen2

Instead of using them to attach to the bar, I see them as having greater applications moving goals. Simple: Powerful magnet + pnumatic detacher = easy goal dragger. This solves the problem of having nothing to grab onto. It also solves the problem or precisely aligning a mechanism w/ the goal.

Sorry, but the goals are made of aluminum and aluminum will not be attracted to the magnet.

-Dave

[Adam Y.]

Neodymium magnets are easy and cheap to come by so
price is not a factor. These magnets are dangerous and care should be used handling them. Here are the reasons:
a) They shatter easily. The force of two magnets attaching to each other is enough to break them and cause shrapenel to fly.
b) They can seriously hurt someone. Companies warn people about the power of the little magnets. Bigger ones could accidentally break bones unless care is taken.
c) Once they are attached to something they are really hard to separate. I am not really sure if this would be an safety issue but you would have to be design the robot with some way to easily deattach the magnet.
d) Aparently they can affect pacemakers and other medical devices.
e) They can ignite accidently and burn very fast like magnesium does.
More Safety Tips Wow
Even More Tips
The Japanese have used these magnets with a lot of success in their sumo robots. They actually fought with their robots upside down.
Here is another link to more information:
Another supplier/Faq on magnets

[Rickertsen2]

Originally Posted by DKolberg

Sorry, but the goals are made of aluminum and aluminum will not be attracted to the magnet.

-Dave

Are you sure? I thought they were steel diamond plate on the side. I will have to check this later.

[Rickertsen2]

Originally Posted by Adam Y.

Neodymium magnets are easy and cheap to come by so
price is not a factor. These magnets are dangerous and care should be used handling them. Here are the reasons:
a) They shatter easily. The force of two magnets attaching to each other is enough to break them and cause shrapenel to fly.
b) They can seriously hurt someone. Companies warn people about the power of the little magnets. Bigger ones could accidentally break bones unless care is taken.
c) Once they are attached to something they are really hard to separate. I am not really sure if this would be an safety issue but you would have to be design the robot with some way to easily deattach the magnet.
d) Aparently they can affect pacemakers and other medical devices.
e) They can ignite accidently and burn very fast like magnesium does.
More Safety Tips Wow
Even More Tips
The Japanese have used these magnets with a lot of success in their sumo robots. They actually fought with their robots upside down.
Here is another link to more information:
Another supplier/Faq on magnets

Add keep them away from computers. I just got one too close to my monitor, and ouch! I'm not talking about magnetizing the shadow mask/apature grill and distorting the colors either. The magnet was soo strong that it bent and stretched a few hunderd of the shadow mask wires!! I now have irreparable black lines across about the middle quarter of my screen. I can hardly see what i am typing. Ooops!!! I guess it's my own dumb fault. At least this isn't my good monitor. (or i wouldn't have been messing w/magnets.) (switches monitors)

----------edit------------
Haha. If i hit the monitor hard enough, the bent wires oscillate and i can see the oscillations almost as if i were lookign at an oscilliscope because of the scanning of monitor highlighting them.

O joy, i also just realized its now probably emitting low levels of X-rays as the electron beam bounces off the bent shadow mask wires at undezired angles. (emits X-rays, which are normally emitted backward and adsorbed by the lead infused glass in the back.)

[Adam Y.]

Add keep them away from computers. I just got one too close to my monitor, and ouch! I'm not talking about magnetizing the shadow mask/apature grill and distorting the colors either. The magnet was soo strong that it bent and stretched a few hunderd of the shadow mask wires!! I now have irreparable black lines across about the middle quarter of my screen. I can hardly see what i am typing. Ooops!!! I guess it's my own dumb fault. At least this isn't my good monitor. (or i wouldn't have been messing w/magnets.) (switches monitors)

If you ever get a hold of a black and white television have fun with the magnets. They do no damage the cvt/phospher screen and the magnets actually distort the screen. It is pretty cool.

[Rickertsen2]

Originally Posted by Adam Y.

If you ever get a hold of a black and white television have fun with the magnets. They do no damage the cvt/phospher screen and the magnets actually distort the screen. It is pretty cool.

And once you finally get bored of that, take it apart and rip out the beefy flyback transformer that most old B/W TVs have and build yourself a tazer sparky thingy. There are are actually alot of useful components in old TVs.

[ggoldman]

Maybe a theory would be not to use the magnet to hold up the robot, but maybe help guide an arm with a latchin device right to the pole:

Heres an example:

Robot "FRED" has a slightly flimsly arm that can reach the height of the bar with a latch that will grip onto the bar once it is close enough to it.

The drive runs the robot under the bar and the magnet on top of the slightly flimsy arm attracts to bar with little effor from the driver to position the bot. The robot then lowers its latch which is now a perfect distance from the bar because of the magnet.

Maybe that has some use?


Other wise, the weight to power ratio of a magnet to lift 130 pounds would not be too efficient.


Gabe Goldman

[Rickertsen2]

Originally Posted by ggoldman

Other wise, the weight to power ratio of a magnet to lift 130 pounds would not be too efficient.


Gabe Goldman

With typical magnets yes, with neo magnets this iisn't a prob at all. A 1ib neodynium magnet could probably easibly lift 2 robots.

[ggoldman]

I stand corrected, havent heard of neo magnets. But if a 1 lb mass of neo magnet can hold that much force, it's field will most likely effect robot controllers or maybe "latch magnetically" onto other robots inadvertantly.


If I were an inspector, and my metallic clipboard got stuck to your magnet while I was reviewing your bot, I would be concerned

Gabe Goldman

[Rickertsen2]

Originally Posted by ggoldman

I stand corrected, havent heard of neo magnets. But if a 1 lb mass of neo magnet can hold that much force, it's field will most likely effect robot controllers or maybe "latch magnetically" onto other robots inadvertantly.


If I were an inspector, and my metallic clipboard got stuck to your magnet while I was reviewing your bot, I would be concerned

Gabe Goldman

Lol.

[Al Skierkiewicz]

Originally Posted by Rickertsen2

Add keep them away from computers. I just got one too close to my monitor, and ouch! I'm not talking about magnetizing the shadow mask/apature grill and distorting the colors either. The magnet was soo strong that it bent and stretched a few hunderd of the shadow mask wires!!

James, Could you explain this in a little more detail? Exactly where did you apply the magnet and what type of monitor are you using? Are the black lines vertical or horizontal? Don't worry about additional xray, the radiation is produced when the electron beam strikes the faceplate due to the high voltage. (30-45 KV)

[Rickertsen2]

Originally Posted by Al Skierkiewicz

James, Could you explain this in a little more detail? Exactly where did you apply the magnet and what type of monitor are you using? Are the black lines vertical or horizontal? Don't worry about additional xray, the radiation is produced when the electron beam strikes the faceplate due to the high voltage. (30-45 KV)

Some monitors(especially those made by Sony) and a very few tvs use an array of VERY thin wires rather than a plate thing for the shadow mask. If you can see 2-4 VERY VERY thin horizontal lines acroos your screen then your screen uses wires. (the horizontal lines are support wires). Anyway, I put the magnet right up to the screen and bent/tangled/stretched the wires. There are now lots of little thin vertical line across the screen. The reason i mentioned X-rays is that since there are now gaps in the grid, it seems like electrons hittign the side of the gaps in the grid would emit X-rays at anglis in front of the screen. (i know its probably harmless amounts)

[Al Skierkiewicz]

Originally Posted by Rickertsen2

Some monitors(especially those made by Sony) ...array of VERY thin phosphor coated wires rather than a plate thing for the apeture grill. If you can see 2-4 VERY VERY thin horizontal lines acroos your screen then your screen uses wires. (the horizontal lines are support wires). Anyway, I put the magnet right up to the screen and bent/tangled/stretched the wires. There are now lots of little thin vertical line across the screen. The reason i mentioned X-rays is that since there are now gaps in the grid, it seems like electrons hittign the side of the gaps in the grid would emit X-rays at anglis in front of the screen. (i know its probably harmless amounts)

James,
I work with a man who worked at Sony for many years and this is his opinion...
The high resolution Trinitron tube has a very fine shadow mask to match the small phosphor stripes on the front of the tube. The electrons from the three color guns pass through the slots in the shadow mask at different angles to energize the three color phosphors printed on the inside of the faceplate. The shadow mask is so fine that changes in temperature were affecting the beam landing so Sony introduced a support structure that compensated for the temperature and supported the very fine mask. Those are the two fine black lines you see running horizontally at about a third and two thirds of the screen height. The metal parts of the picture tube are affected by magnetic fields like speaker magnets and the earth's magnetic field. There is a degaussing coil built around the picture tube that generates a moving and variable intesity field, at turn on, that is supposed to erase the magnetic field taken on by the metal parts. What we feel has taken place is the magnet you applied has generated such a strong field, the degaussing coil cannot overcome it. There are coils that are used by service people that can erase this field. What we think is occuring is that the magnetic field on the shadow mask is causing the electrons to strike the black stripes between the color phosphors on the faceplate of the tube and that is what is causing the black vertical strips. If you look close, you should see the there is faint color at the very edges of the black lines. If this is the case, you need to see if you can borrow one of the service deguassing coils or take it to a TV shop and let them try to deguass it.

[Rickertsen2]

Originally Posted by Al Skierkiewicz

James,
I work with a man who worked at Sony for many years and this is his opinion...
The high resolution Trinitron tube has a very fine shadow mask to match the small phosphor stripes on the front of the tube. The electrons from the three color guns pass through the slots in the shadow mask at different angles to energize the three color phosphors printed on the inside of the faceplate. The shadow mask is so fine that changes in temperature were affecting the beam landing so Sony introduced a support structure that compensated for the temperature and supported the very fine mask. Those are the two fine black lines you see running horizontally at about a third and two thirds of the screen height. The metal parts of the picture tube are affected by magnetic fields like speaker magnets and the earth's magnetic field. There is a degaussing coil built around the picture tube that generates a moving and variable intesity field, at turn on, that is supposed to erase the magnetic field taken on by the metal parts. What we feel has taken place is the magnet you applied has generated such a strong field, the degaussing coil cannot overcome it. There are coils that are used by service people that can erase this field. What we think is occuring is that the magnetic field on the shadow mask is causing the electrons to strike the black stripes between the color phosphors on the faceplate of the tube and that is what is causing the black vertical strips. If you look close, you should see the there is faint color at the very edges of the black lines. If this is the case, you need to see if you can borrow one of the service deguassing coils or take it to a TV shop and let them try to deguass it.

Hmm sounds possible(from my limited understanding of CRTs). Its seems to me that if the shadow mask were this magnetized, the colors would be distorted. I don't have access ot a degaussing coil, and i don't feel like payign for somethign soo simple. From my understanding, a degaussing coil is nothign more than a big 60hz electromagnet that plugs into the wall. Anybody know how many turns of what radius i need to build one?

I just realized somehting about the vibrating patterns when i hit the screen. Its not the actual lines that are moving, but rather it seems they are casting phantom vibrating lines beside themselves. Also, Its hard to tell, but some of the lines do seem to have colors bordering them.