magnetically activated switches

[heath robinson]

Hi all.

This is Land rover related, but you'll have to bear with me. I'm looking for a magnetically activated switch. I've looked at a fair few reed switches, but they all seem a little flimsy for my needs. I'd ideally like to find a switch that will activate when a magnet like this is placed near it. When I say near, I mean a few mm away, say on the other side of some birmabrite or a bit of trim. I need the switch to be 12v, and handle enough current for, say, a fuel pump, or maybe a switched ignition line.

Do you see where I'm going with this? Sneaky, ain't it.

Maybe some form of microswitch could be used, but I'd rather just a beefy reed switch if possible.

Any thoughts or advice?

Thanks.

[Superpants]

Loads of options in RS:

Lots of lovely proximity switches

Farnell do a similar range.

The other option is to pull one out of a disused laser printer or photocopier- sometimes find reed switches in them

[errol209]

Beefy and reed switch don't go together well: have you thought of using the reed switch to trigger a small relay which then triggers / latches the bigger power relay? You could use a Hall Effect switch instead of a reed, solid state so no broken glass bits either.

Edit: the 3A ones in Superpants' link aren't big enough to switch a pump directly, but the 1A sort will easily fire the coil on a 12V automotive relay

[FridgeFreezer]

Burglar alarm door switches, can be had for around £1 from the likes of CPC.

[heath robinson]

Nicely done. I think I'll have to go for a relay, which I was trying to avoid, but hey ho. I figured that a magnetic switch is going to be far beyond the ken of the average light-fingered individual, and if behind something, impossible to spot.

Thanks.

Jake

[Night Train]

Be careful pulling those magnets in your pocket though, aside from the damage they can do to your credit cards, when they stick you want to keep your skin from being trapped between them.

[FridgeFreezer]

You could always wire the cig lighter in series with a relay, so you have to push the lighter button in to start the car.

[RichardAllen]

You could always wire the cig lighter in series with a relay, so you have to push the lighter button in to start the car.

On that basis Fridge, you could have a large red illuminated push button in the middle of the dash with START written on it. It would be more secure if it was not actually wired up to anything !

Hat, coat, umbrella, keys, passport . . . .

[heath robinson]

On that basis Fridge, you could have a large red illuminated push button in the middle of the dash with START written on it. It would be more secure if it was not actually wired up to anything !

There's a thread HERE about securing yer lock-up, that has some amazing tales of mis-direction. Seems like stupid thieves are fairly common.

Following on from ideas in that thread, I could link the started button to a smoke grenade and a massively loud alarm, although I'd need a switch to stop my mates from pushing it.

I just don't think that I can bring myself to sully my truck with one of those chav-tastic red "Start" buttons...

I do like the idea of an idiot button. It wouldn't necessarily need to be that blatant though. If the thing won't start, they'll probably look for small switches hidden away. Have one or two that aren't too well hidden.

The ciggy lighter is nice. It never worked anyway. Just have to pray that the pikey doesn't have a fag to calm his nerves while he tries to get the thing to start. Could always have it the other way around, so that the thing WON'T start if the ciggy lighter's in. Not won't run though, or again my mates could inadvertently cause calamities.

I also thought that a latching button switch under a small hole in the trim might be good, poke a match through to toggle it.

[heath robinson]

No need to worry Night Train, once bitten twice bashful... The bigger the magnet, the bigger the mistake, and I've played with some fairly large magnets.

I was more thinking of leaving it on the dash, and just sliding it to the right place to start it. Blatant, but sneaky.

[simonr]

You can always mount the switch and the magnet in the dash - just too far away from one another to operate. Then use a small chunk of steel (keyring) to extend the field from the magnet to the switch.

Si

[ThreeSheds]

There is a way of wiring the horn into the starting/running system such that the engine will turn but not pick up unless the horn button has been pressed first - the last thing a tealeaf is going to do is press the horn I reckon...

Roger

(p.s. my use of the RRC is not that frequent so my anti-theft solution is to remove a vital ignition component and hide it in the house - I wouldn't have posted the above idea if I actually used it myself)

[Night Train]

There is a way of wiring the horn into the starting/running system such that the engine will turn but not pick up unless the horn button has been pressed first - the last thing a tealeaf is going to do is press the horn I reckon...

Roger

In my MGB of old I had a number of high pitch, high volume sounders hidden around the interior that were wired to the ignition. Unless they were isolated first, by hidden switches, the noise was almost intollerable while trying to start the car.

I like Simon's idea.

[FridgeFreezer]

I find mounting the dashboard on the ceiling and not labelling any of the buttons or switches works quite well the MOT man always tells me to sit in it to operate the switches 'cos he can't work it out

[TheRecklessEngineer]

I work on the theory that if anyone tried to steal mine, they'd never find 1st on a series box and wouldn't be able to manage the non-power steering with atrocious lock.

[elbekko]

I've heard tales of a bloke in a Mini just taking the gearshift lever with him when he left it somewhere. Sounds like a pretty effective solution I must say, not many thieves walking around with spare levers

[zardos]

I've heard tales of a bloke in a Mini just taking the gearshift lever with him when he left it somewhere. Sounds like a pretty effective solution I must say, not many thieves walking around with spare levers

I take my steering wheel off my 90

[heath robinson]

I used to pop the king lead off the dizzy or coil just enough that it wouldn't fire, but it was an arse to have to lift the bonnet in the rain, and eventually the end dropped off one of my Magnecore leads so that stopped, sharpish.

[landroversforever]

Friends dad made his gear lever quick release! all hidden by the gaiter. Was a Nissan pick up.

Like the idea of a magnetic something

[Aragorn]

I rigged up some deterrants it a mates old nova. We installed two extra switches in the blanks in the dash, one labelled as front fogs and the other labelled as heated seats, so they blended in nicely.

One of the switches was connected to the fuel pump, and the other triggered both the cars main horn, and a horn mounted in the footwell behind the dash via a latching relay.

With the ignition off, he'd turn the "fuel" switch off and the "horn" switch on. If a scrote was to try to hot wire it, as soon as the ignition was powered up, the horns would start blasting, and it bloody hurt!

[TheRecklessEngineer]

I've got one of these: eBay linky

Ok, so it's still sat on my inventing table, but the idea is there...

[LiftedDisco]

I've got one of these: eBay linky

Ok, so it's still sat on my inventing table, but the idea is there...

James....

Thank you, thank you, thank you!

I have one of these fitted to my Disco and didn't know where it came from and as I only have one key set, I am totally paranoid about losing the damn thing!

Have asked at my local specialist and he just shook his head.

e-bay chap, here I come!

Cheers, once again!

[heath robinson]

I like it! Perhaps one or the other of you could send me a PM about how to fit one (No point in giving the game away).

Thanks.

[LiftedDisco]

PM sent

[jmattley]

Lifted disco, how did you fit it to your motor then? what's it wired to and how do you activate it? Do you just rest it on the dash or what? I'd love something like this!

Cheers!