Fu**'n magnets, how do they work?

carries an axe

carries an axe

meat bone meat meat meat
I developed a scheme to keep my feet on my wheelchair pedals.
I'm going to take a small hole saw and cut a small depression in the heel of my shoes.
I will then insert a magnet into it and epoxy it in place.

(Think like James Bond from Goldfinger and his little radio transmitter)
Then I'm going to epoxy a strong magnet either under or on top of the wheelchair pedals.

That way if I spasm I never kicked my feet off and if I drive over a strong bump they will stay in place.

The problem is I have no idea how to gauge the strength of magnets.

Can anyone link me to a place to buy the strongest one inch or so diameter magnets that won't do something weird to me like permanently afix my shoes, or sweep the street of every razor blade hypodermic needle and nail I come across:laughing
 
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carries an axe

carries an axe

meat bone meat meat meat
byke said:
How will you disconnect? And will your shoes go with you when you do?
Click to expand...
Caregiver would just pull my feet off when they need to so they can't be so strong as to prevent that. It's mostly the occasional light spasm where I flip my foot off but the worst case scenario is a big giant bump driving down the street like a tree root or something. Then my foot tends to go flying
 
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CocoLoco

CocoLoco

FN #5
carries an axe said:
I developed a scheme to keep my feet on my wheelchair pedals.
I'm going to take a small hole saw and cut a small depression in the heel of my shoes.
I will then insert a magnet into it and epoxy it in place.

(Think like James Bond from Goldfinger and his little radio transmitter)
Then I'm going to epoxy a strong magnet either under or on top of the wheelchair pedals.

That way if I spasm I never kicked my feet off and if I drive over a strong bump they will stay in place.

The problem is I have no idea how to gauge the strength of magnets.

Can anyone link me to a place to buy the strongest one inch or so diameter magnets that won't do something weird to me like permanently afix my shoes, or sweep the street of every razor blade hypodermic needle and nail I come across:laughing
Click to expand...

May I make a suggestion? Put a couple of pieces of metal into your shoes and set up an electromagnet on your chair that you can turn on and off. That way you only have the megnetic effect when you want it.

I don't know how to set up the electromagnet but I'm sure one of our resident science experts does.
 
carries an axe

carries an axe

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CocoLoco said:
May I make a suggestion? Put a couple of pieces of metal into your shoes and set up an electromagnet on your chair that you can turn on and off. That way you only have the megnetic effect when you want it.

I don't know how to set up the electromagnet but I'm sure one of our resident science experts does.
Click to expand...

Yeah I guess it wouldn't have to be two magnets. Could just be a piece of Steel in my shoe and a magnet on the pedal.

I really don't want to complicate things with wires and buttons KISS and all that stuff
 
Yakoo752

Yakoo752

USN
Why not neodymium magnets?

They make the most sense to me. Permanent and tiny and strong

With the gap created from inserting them into the sole they should be able to be slid off. Horizontal force will remove not vertical force.
 
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CocoLoco

CocoLoco

FN #5
carries an axe said:
Yeah I guess it wouldn't have to be two magnets. Could just be a piece of Steel in my shoe and a magnet on the pedal.

I really don't want to complicate things with wires and buttons KISS and all that stuff
Click to expand...

I agree. Just being able to switch it on/off would solve the issue of having to figure out the required strength of magnets. The concern would be figuring out how much current you'd need to reach the magnetic strength desired (if memory serves current controls the strength of the magnetic field). I don't know how it would affect the operational time of your chair.

Something like this would do the trick I'd imagine:30+ lb of force each.
https://www.walmart.com/ip/12V-39-7LB-18Kg-Electric-Lifting-Magnet-Electromagnet-Solenoid-Lift-Holding-34mm/46513175?wmlspartner=wlpa&selectedSellerId=571&adid=22222222227034717496&wl0=&wl1=g&wl2=t&wl3=75440220634&wl4=pla-175427344594&wl5=9032007&wl6=&wl7=&wl8=&wl9=pla&wl10=111838760&wl11=online&wl12=46513175&wl13=&veh=sem
 
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Yakoo752

Yakoo752

USN
My question to you would be

Since magnets will always try and center themselves do you put yourself at risk (bedsores) by always having your feet in exactly the same position.
 
carries an axe

carries an axe

meat bone meat meat meat
CocoLoco said:
I agree. Just being able to switch it on/off would solve the issue of having to figure out the required strength of magnets. The concern would be figuring out how much current you'd need to reach the magnetic strength desired (if memory serves current controls the strength of the magnetic field). I don't know how it would affect the operational time of your chair.
Click to expand...

Yeah I get what you're saying but having dealt with other electric systems for various small things the complication tend to lead to failure.

Like my urine bag emptier. Failure equals explosion of Pee
 
carries an axe

carries an axe

meat bone meat meat meat
Yakoo752 said:
My question to you would be

Since magnets will always try and center themselves do you put yourself at risk (bedsores) by always having your feet in exactly the same position.
Click to expand...

No I can raise my legs up horizontally using the chair servos
 
carries an axe

carries an axe

meat bone meat meat meat
byke said:
Too weak, but I like CC's idea. I think you're going to have a hard time finding ones strong enough to do what you want, but weak enough to not pull out from your shoe, but maybe one of these...

https://www.mcmaster.com/#58605K41
https://www.mcmaster.com/#5862k38
Click to expand...

Looks like these two are the right size. I already have some epoxy

magnets

drill bit
Nice and Powerful but if this chart shows that you can slide them off with your fingers I'm guessing I'm going to need that power
CEGRozWLRmOe._UX300_TTW__.jpg
 
byke

byke

Well-known member
As yakoo mentioned, it'll all depend on that gap. You'll want to adjust it with some material you cover the magnets with. I'd guess somewhere between 1/8" and 1/4" will be good.
 
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