# Electromagnetic repulsion

Discussion in 'The Projects Forum' started by SplitInfinity, Mar 9, 2013.

1. ### SplitInfinity Thread Starter Member

Mar 3, 2013
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Georacer...this is kind of a simplistic solution to cars on the same track bumping into one another...but I think it will work as well as save you a whole lot of work.

You could either use some of the electricity used to power the cars for use in two Elecromagnets on the front and back of each car making certain that the back of one car would repell magnetically the front electromagnet of a car behind it.

You could just attach magnets that could be switched to line up repelling poles...but this might not be strong enough.

As far as changing poles on the electromagnets so that any car could be placed first or second...I am sure you could build some type of a polarity switch.

This might drain some power needed for racing...but again...I am sure this could be compensated for.

Split Infinity

Last edited by a moderator: Mar 13, 2013
2. ### Georacer Moderator

Nov 25, 2009
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I don't see how this could work.

Based on experience, your solution should not weigh more than 5gr per car and cost more than \$5 per car.

Finally, when the first car is stopped in the red light, the others shouldn't push it through the intersection.

Can you come up with an implementation, working on 12V?

3. ### SplitInfinity Thread Starter Member

Mar 3, 2013
369
9
After looking at what the requirements are...I relise now that doing this would not work given the set of parameters you are confined to.

Forgive me but the idea just popped into my head and I should have given the specifics of what was required more due.

But...I do believe using a system of electromagnetic repultion either using some power from the given supply or perhaps creating the needed power from the movement of the cars would seem to be a neet trick.

It was just a thought.

Split Infinity

4. ### thatoneguy AAC Fanatic!

Feb 19, 2009
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731
This solution simply changes the force of impact from physical to magnetic. The front car will still need to not move due to the bumps from the back, unless it had a locking pin poke up in front of the car.

Same effect could be had by putting Neo magnets on the front and back of the cars, with like poles outward. They would repel each other, no electricity needed. That doesn't change the fact the moving car has kinetic energy and the stopped car does not.

5. ### Georacer Moderator

Nov 25, 2009
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Yes, that explains it better why this couldn't work. Thanks.

6. ### SplitInfinity Thread Starter Member

Mar 3, 2013
369
9
I have a friend who works on developing Mag-Lev trains and other Mag-Lev prototypes. I remember a conversation we had about how two Mag-Lev test vehicles kept from bumping or ramming into the front and rears of each other.

He was developing and testing a system of E.M. repultion at speed and an E.M. Lockdown at stop as well as a sensor system that would slow the speed of such a vehicle when a vehicle in front of it either came to a stop or was slowing down as forward E.M. directed thrust would be altered in each vehicle relative to distance to one another, distance to a stopping or stopped vehicle or incompatible acceleration of two vehicles on the same..."Track".

I wonder if such a sensory system could be used with your issue?

Split Infinity

7. ### thatoneguy AAC Fanatic!

Feb 19, 2009
6,349
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Sensors alone won't cut it.

The entire track and budget would need to be thrown out to change Georacer's project.

To clamp down a car implies there is a magnet on the underside of each car that a large electromagnet under the track can clamp. Distance is rather far, relative to mag-lev (Depending on type of lev), so a lot of power is needed.

Assuming that is done, the first car is now stopped at the light, and there are permanent magnets with like poles out on all the cars. The cars will have an oscillation/settling period to waste excess energy through friction with tires on track. It wouldn't be neat and tidy without making each entire lane have car sized control paths.

It's possible, but not simple, especially considering it needs to be done with 74xx logic.

8. ### SplitInfinity Thread Starter Member

Mar 3, 2013
369
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Gotcha.

I guess the idea seems easier than it's implementation.

How much power do you believe could be generated by using the movement of the cars to do so?

Split Infinity

9. ### Wendy Moderator

Mar 24, 2008
21,529
2,973
After watching this thread stray further and further from the original topic, I have decided it needed a thread of its own. Hijacking is not allowed on AAC.

This was split from Project: Automated Slot Car Intersection

10. ### thatoneguy AAC Fanatic!

Feb 19, 2009
6,349
731
Sorry for continuing. I shouldn't have gotten into the discussion.

11. ### Georacer Moderator

Nov 25, 2009
5,154
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No biggie. It's what mod tools are for.

12. ### THE_RB AAC Fanatic!

Feb 11, 2008
5,430
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Yep. I would put a tiny but strong neo magnet on the back of each car, and a reed switch in the front of each car.

Assuming the reed switch was normally closed the car would drive forward until it got close to the car in front of it, then when close enough the reed switch would open and cut power to the rear car.

The rear car would stop, and would only start again after the front car moves away.

Even with a transistor and a cap for a bit of a time delay before re-starting the motor I think that would fit in 5g and \$5 limits.

Georacer likes this.
13. ### Georacer Moderator

Nov 25, 2009
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That' actually very clever! This solution is very neat because it alleviates the need of logic in the tracks.

However, the implementation isn't too straightforward, as for the intersection logic to work, it must be able to count how many cars wait for the light. Currently. this is done by assuming that only one car sits per segment. This way, one tin foil sensor can be laid down for each segment, and each segment only.

Of course, I found out about reed switches only last year.

14. ### SplitInfinity Thread Starter Member

Mar 3, 2013
369
9
Sorry about that. Just trying to help.
Split Infinity

15. ### SplitInfinity Thread Starter Member

Mar 3, 2013
369
9
Very nice RB.
Split Infinity