Door switch alternatives

[Bitsyncmaster]

I guess this would be a good place to post your experiments for replacing the door switch. Also could be used for the engine cover, hood and glove box.

My idea is to use a mercury tilt switch mounted in the moving door. These switches are not as common anymore. I bought 40 of them on EBay from China for 5 or 10 bucks.

Here is my mounting of the glass switch. The case is just a 1/2" high piece of vinyl porch rail. It's the 1.25" square uprights. I mounted two 1/4" flat tabs for connections and after soldering the switch, filled it with epoxy.

[dvonk]

nice, i like mercury switches. i have a vintage mercury light switch in one of the rooms of my house. id have to say that mercury is my favorite element, despite its toxicity... although you wont have to worry this switch breaking when its surrounded by all that epoxy.

do you know at approximately what angle the switch activates?

[Bitsyncmaster]

nice, i like mercury switches. i have a vintage mercury light switch in one of the rooms of my house. id have to say that mercury is my favorite element, despite its toxicity... although you wont have to worry this switch breaking when its surrounded by all that epoxy.

do you know at approximately what angle the switch activates?

It's pretty much an on or off any angle off of level. The glass tube is straight and the ball of mercury fills one end, the two pins (wires) are in the other end.

[Farrar]

FMPS.gif

[TTait]

(all below is meant in the spirit of good fun and debate)

The door switches are not just to turn the lights on or off, they are also meant to alert you when the door is open, or more correctly - not quite closed.

The mercury switch isn't going to do that... If you adjust it to within a gnats ass, the lights will flash whenever you accelerate, turn, or even pass gas.

The only way to get both doors to work accurately would be to only park on a perfectly level surface every time. Even a less accurate compromise that gave up on the door ajar function but would turn the door lights on and off, may well flicker when you go around a good turn.

Two options to consider for a more accurate switch with no moving parts or brushes to wear and oxidize would be:

Proximity sensor - while you can adjust it a lot tighter than a mercury switch, and it would be unaffected by g forces, it would still be tough to get the accuracy to get the door open idiot light to work properly. Its a little pricey too.

An Optical sensor - Laser based perhaps? With this option you would drill two perfectly aligned pinholes - one in the door and one in the jamb, and put an emitter behind one and a sensor behind the other. With a little effort you could set it to be accurate - but you're drilling precision holes into your car...

Now that I've been just plain annoying, I should continue by being obvious and annoying.

You should also keep in mind that the switch has mercury inside a glass tube inside a door that probably has 5g's plus of deceleration when the door closes. When it breaks, it will drip. Into your eye (perhaps with a little ground glass washed in with it!) as you get out.

Unless you frequently have syphilis you probably don't want that mercury floating around in your body (the stainless one, or your own body).

[Bitsyncmaster]

I agree that the "door ajar" function will be lost with the mercury switch but I'm willing to bet 50% or more cars will not indicate both door latches are not latched with the OEM switch. I know a few times I have had to pull off the road to fully close my door. The door will rattle if both latches are not engaged.

The problem with a more elaborate "door switch" is you must keep it powered all the time. So power draw on the battery has to be considered.

If you adjust your door switch to only work with a latched door then you risk draining your battery when you park your car.

[Ron]

Wouldn't using accessory (instead of battery) power solve both parking problems???

[Bitsyncmaster]

Wouldn't using accessory (instead of battery) power solve both parking problems???

Then you would not get dome and door lights when you go to open the car.

[Ron]

Then you would not get dome and door lights when you go to open the car.

Hehe...both of us should of looked at the schematic first...It is already running off of accessory!

[TTait]

Dash indicator runs off accessory, while dome and door lights are always on.

The question is which of those sources would you use to power the new switch if you used an active switching technology... back to above if you run it off the constant power then your switches will draw power and run down the battery, regardless of whether or not the doors are open or closed. Run it off accessory, and the dome lights won't come on - even though the dome lights have power available, the switch would not be active.