What is a dumb thing you can do with magnets?

[VictoryNeverFail]

im bored

[HansonKerman]

stickem together 

eat them

drink them

smell them

touch them to a compass

throw them out of a window 

annoy Bill with them 

fascinate bob with them 

throw Jeb’s plane off course

merge posts with then

sit on them

marvel at the power of magnetics

destroy the earth by replacing the core with them

taste the SUN

stickem together

[cubinator]

Attach one to some foam and float it in water. Boom, magnetic compass!

[RealKerbal3x]

Put one on top of a table and one underneath. If you can move the bottom one surreptitiously enough, people will think you're using the Force

[cubinator]

18 minutes ago, HansonKerman said:

eat them

drink them

Also, no, don't ever do this. Your mortal form can't handle that kind of power.

[HansonKerman]

uncalibrate GLaDOS with them 

murder a robot with them

plug one in

attach them to your feet like a horseshoe

1 hour ago, VictoryNeverFail said:

 

im bored

 

vanquish boredom with them

[StrandedonEarth]

Try to push the same poles together against the repulsion 

If magnets are ingested, they will try to stick together inside your digestive tract, causing all kinds of problems including obstructions. DON’T SWALLOW MAGNETS!!!!!

24 minutes ago, cubinator said:

Attach one to some foam and float it in water. Boom, magnetic compass!

If you magnetize a needle, you can carefully float it on the surface tension of the water, no floatation device needed. Warranty void if any amount of soap is in the water. 

[HansonKerman]

47 minutes ago, StrandedonEarth said:

Try to push the same poles together against the repulsion 

that is unreasonably fun. I love doing that.

[Clamp-o-Tron]

Attempt to hold a sun with them.

[cubinator]

15 minutes ago, Clamp-o-Tron said:

Attempt to hold a sun with them.

DIY one helium atom.

[Shpaget]

If you have a CRT TV, you can make rainbows!

[adsii1970]

Stick a paper towel full of cat treats to the top of the refrigerator door... 

My poor cat worked for two hours trying to get them down...

 

[StrandedonEarth]

19 minutes ago, adsii1970 said:

Stick a paper towel full of cat treats to the top of the refrigerator door... 

My poor cat worked for two hours trying to get them down...

 

My mountain lab would have been happy to render assistance. Whether or not there’d be anything left for the cat is a different matter...

[Vanamonde]

The opinions and ideas expressed in this thread are not recommended or endorsed by Kerbal Space Program, the forum, Squad, Take Two, Private Division, me, nor really anyone else. 

DO NOT TRY THIS AT HOME. 

[Clamp-o-Tron]

2 hours ago, Clamp-o-Tron said:

Attempt to hold a sun with them.

Even better: PROPEL A SPACECRAFT WITH THAT

[Castille7]

Make an almost Perpetual Motion Contraption

[HansonKerman]

2 hours ago, Vanamonde said:

The opinions and ideas expressed in this thread are not recommended or endorsed by Kerbal Space Program, the forum, Squad, Take Two, Private Division, me, nor really anyone else. 

DO NOT TRY THIS AT HOME. 

*starts boring operation to the core of earth*

3 hours ago, StrandedonEarth said:

My mountain lab would have been happy to render assistance. Whether or not there’d be anything left for the cat is a different matter...

The Schrödinger’s cat paradox which details that a cat in a box is simultaneously alive and dead was used by Schrödinger as an excuse for killing cats.

3 hours ago, adsii1970 said:

Stick a paper towel full of cat treats to the top of the refrigerator door... 

My poor cat worked for two hours trying to get them down...

 

do that again but this time take a video. Also... you did give them a few afterwards, right

[adsii1970]

33 minutes ago, HansonKerman said:

Do that again but this time take a video. Also... you did give them a few afterwards, right

Not for a while. He has to go to the vet every two weeks to get some broken-off  teeth pulled. Poor buddy is in a little pain. 

[HansonKerman]

37 minutes ago, adsii1970 said:

Not for a while. He has to go to the vet every two weeks to get some broken-off  teeth pulled. Poor buddy is in a little pain. 

oof. I don’t have a cat (mom has problems, not even allergies), and I don’t intend on getting one but I love them anyway. Keep it up kitty. If you’re having trouble, you can always...

M A G N E T

[Nuke]

my latest magnetic project was building hall encoders and rotation sensors, it was quasi-successful. the encoders were most successful mostly because they are just a binary output indicating when the magnetic field intersecting the sensor changes polarity. it mostly just requires putting a bunch of tiny magnets into a 3d printed rotor with alternating polarity. one sensor isnt enough to detect direction of motion, but a second one 90 degrees out of phase lets you figure that out. so my print included a stator where i could insert my sensors at the right angles. of course at the end of the day i think you can get more resolution out of optical encoders simply because its easier to make a tiny slit in a plastic disc than it is to make a tiny neodymium magnet with enough field for the sensor to pick up on. i was using some 2x2x3mm magnets, which are already too small to work with, and i think i only got like 32 ticks/rotation which managed to fit in a 1 inch knob (though a bigger knob for more magnets could increase that a lot). for this i used a us1881 hall latch, in that they only detect a change in polarity and not the field strength. 

the rotation sensors were intended to culminate in a drop in replacement for your standard panel mount potentiometer. i based my initial design on a really old skool style potentiometer (they are so old they were made in america). now i hate to destroy a fine example of mil spec american pots that are still fairly good dispite being maybe 50 years old, but i needed the bearings and shaft to make my own sensor (anyone wishing me not to destroy this junk historical artifact in the future, pls donate one micro lathe). these are a different style than the ones i want to replace, but it was a good place to start. i printed a housing and press fit the berings into them. the shaft accepta a 3d printed armature at one end with the other side being the input. the armature is just 2 magnets each on their own prong of a 3d printed fork that rotates around the hall sensor, in north-south north south-order. the sensor itself, a ss49e linear hall sensor sits on a small pcb with support components that screws into the back of the housing. i made 4 of these so far. the first 2 were so successful and i used them in a joystick related project. recently i decided that i needed another set, but since the first set was based around a pair of magnets from my parts bin which seem to be the perfect size and shape for this application. try as i might i couldn't find any magnets of similar dimensions for sale on the internet. i tried using the magnets i bought for the encoders, but they seemed to be too weak for reliable detection in this application. so i went through my parts bin and found some larger mystery magnets. i had to design a new armature and it barely fit in the housing design i had used. only seemed to go together after a lot of filing and sanding. it kind of works but is somewhat non linear, and thats likely something to do with the largeness of the magnets. i figure its a goldilocks problem, finding the right size magnets to produce the right field strength at the right distance. 

but there is a simple way around that. create a table of sensor value vs known angles. then if you have a value straight off the adc, you find the 2 entries in the table that bracket it, and then you can use interpolation to determine the approximate angle. i still need to come up with a jig to test the linearity so i can generate the luts. likely put a stepper motor on the same shaft, sweep the range one step at a time (which is a known quantity determined by the motor's step size), while logging the sensor reading straight from the adc and and current angle the stepper is holding. of course now we are bumping into the limits of the arduino. you can only store so much table in the microcontrollers eeprom or program memory (which are tiny, precious and in demand). 2 bytes is enough for a 16 bit output. since the measurements are taken at a regular interval i can use the array index for this. easy way is one entry per degree, anything else would require a conversion factor somewhere, and store 180 degrees worth of readings, which is 360 bytes and too big for the eeprom. if you are using the stock 10 bit adc you might be able to bit pack and save 6 bits per entry (225 bytes for the whole sweep). another way is to use fewer samples and accept any resulting local nonlinearity. say make the ticks 2 degrees per index and you only need half as many samples. i would need to do both or use a bigger micro. things are complicated if you have multiple sensors that produce different values when you characterize them. 

there are some newer angle sensors (like the hal 835) with the adc, lut table and interpolation hardware (hell its an entire dsp) built in and they usually have pwm or some other digital output. while its nice to have options where i dont have to change my physical design to accomidate the sensor,  the catch is you have to program each sensor and to make matters worse, each sensor has only 3 pins, so you program it by modulating the power pin. this is the most complicated 3 pin part ive ever seen which makes integration difficult. now if i could find one that can run at 3.3v i can use it as my raspberry pi joystick sensor of choice (theres always a gotcha in part selection). 

 

 

On 6/2/2020 at 9:56 AM, cubinator said:

Also, no, don't ever do this. Your mortal form can't handle that kind of power.

this is true, lots of kids have been injured by eating the things. both that the metals might be toxic and they have been know to go through your intestine wall when you swallow more than one. peritonitis is not fun. 

also gauss rifle (unrelated to the rest of the post)

 

Edited June 5, 2020 by Nuke

[HansonKerman]

4 hours ago, Nuke said:

this is true, lots of kids have been injured by eating the things. both that the metals might be toxic and they have been know to go through your intestine wall when you swallow more than one. peritonitis is not fun.

did you not get that it was a joke or something lol. But you are right in that magnets are FUN.

[Guest]

Air, water, fire and earth

 

....... magnets, how do they work

Edited June 6, 2020 by Guest

[Shpaget]

They've got a sticky side and the other, but you don't know which one is which until you put two of them together, and even then they can switch up on you without even realizing. Just like they always switch so they stick to iron, no matter how you turn them. Shifty little magic buggers.

[Clamp-o-Tron]

Made an ion drive today. (Kind of uses them)

[StrandedonEarth]

10 hours ago, HansonKerman said:

did you not get that it was a joke or something lol. But you are right in that magnets are FUN.

Most of us get that it's a joke. But for something that can be a serious health issue, it's worth hammering home DO NOT DO THAT. Just in case someone does not realize that it's a joke. My daughter's (and everybody else's) collection of Polly Pocket dolls/toys were recalled because the tiny magnets could come loose and be swallowed deliberately or accidentally by kids