Electronics solenoid help

i am looking for a contraction solenoid that i can hook up to a sleeve, so it will look and function like a bikes hand brakes.

it will need as much strength as possible and operate on:12v, 10.8v, 9.6v, or 8.4v

bet you'll never guess what I'm gonna use it on

 

i would guess power assisted braking on a push bike.


i think you should get modding then

 

You've been here 7/8 months, that's long enough to know that electronics questions go in the electronics forum.

Moving....

 

i did think about the electronics, but then decided on hardware (since it is hardware) but all that hardware is video cards/NIC's/etc. so i decided against that.

i tried to hedge my bets by putting in the forum with "general" in its name.

sorry.

is there a website where you can order the solenoid off a remote door opener (on a car) for cheap, maybe slightly used or soomething?

"pimp my ride" ~ MTV showed how a remote door opener on a car worked, by a solenoid (the type I'm looking for) pulling the cable instead of the handle doing it. thanks pimp my ride!

warrmr, you're getting colldr sorry, i couldn't help myself!

but for any bike people, a small dynamo generator (off of a light, the generators that rub against the wheel) powering the solenoid assisted brakes, thus a good current (wheels turing fast) will cause a strong pull of the solenoid, while a weak one (wheels turning slowly) will cause it to barely brake.

that way would seem to have two advantages, 1) more precise braking, instead of all-or-nothing; and 2) no heavy batteries to slow you down even when you're not braking.

and with the addition of a latching solenoid (which can hold two or three distances with no current, it latches in place to lock) you can have parking brakes (no one will be able to jack your bike when the wheels won't turn!)

 

All the solenoide I've seen aren't that strong, (at least the 12v ones) only like 1.5 pounds with a .25" stroke. But since you have a dyanamo on it already, you could use a dyanamo as a brake it's self, or an electric motor also.

If you connect the leads of the dyanamo to a low resistance (.25-2 ohm) power resistor, the dynamo becomes hard to turn, slowing you, and with a medium resistance power resistor (4-10) you add extra resistance, making it slightly harder to turn, useful as a brake for coasting downhill.

Or you could use magnetic braking, if you have aluminum rims. What you do is moun't some big powerful neodymium magnets, (take some from hard drives) and mount them to the side of your brake shoes so that they come close but don't touch the rim, even when you really hit the brakes hard. The aluminum has an electric field induced in it by the magnet, giving it a magnetic field also. The fields are opposide, so they attract, slowing the wheel. This is what they use on the drop tower rides, you may notice the fins sticking out of the tower, these are the aluminum fins, (or any other non-magnetic metal) the magnets are on the car.

You can test this with a piece of alu and a strong magnet. I take an old HS with a flat bottom, and move my magnet by it quickly, and it pulls the HS without touching it.