I’m going to light a passenger car with a battery and grain of rice bulbs. My plan is to mount the battery in the ceiling and use a reed switch in the ceiling of the car to turn it off and on and off. After googleing many googles the only reed switches I have been able to find are the ones that need constant contact with a magnet to open a circuit. I know, at least I think I know, that there is a reed switch that open when a magnet is run across it and closes when the magnet is run across it again. Does anyone know the source for such a switch?
I feel your pain. At one time I found a reed switch with 3 leeds, so when a magnent was in range it would throw one way, and out of range it would throw the other.
When I wanted to actually purchase a few of these to do some testing, for the life of me I couldn’t find that same reed switch. I ended up buying several 2 leed reed switches .
My biggest hurdle to overcome is my desire to find a “better way” to do things like illuminate LEDs based on turnout direction or to raise/lower my road crossings when trains approach etc. I have no ambition to build or buy CD (cap discharge) units, tort’s, etc. I’d like to KIS and cheap.
if you don’t get a direct link here and if memory serves me at all I think I was doing google queries using “dpdt reed switch” “3 conductor reed switch”, etc
Sorry not a whole lot of use here /snicker
/ramble off
EDIT
I did mean to make one point though, the reed switch that you’re talking about I do not believe exists. If you do some research on how a magnetic reed switch operates it is a bit different than what you described. Wikipedia had some good info on it. I think you may be able to find a solid state “reed” switch to do what you’re looking for though. If you think about how a magnentic reed switch works, it just moves a metal bar from one place to the next, but always the same movement, same direction, etc. I’m not aware of a way a reed switch can “select” the movement based on the magnetic field it enters.
RAM electronics didn’t have much of the miniature and sub-miniature electronics and no reed switches. Miniatronics is a great site and I’m bookmarking it, but the only reed switches they listed were the momentary type. Thanks non-the-less.
Jason, it appears you are right, there is no such thing as what I’m looking for. It seems that every time I post or answer a post I am more often wrong than right. If a person truly learns from their mistakes, I must be one of the smartest people around.
What you are looking for are called latching magnetic reed switches. I have purchased them from several suppliers over the years. There is one listed in the walthers catalog, 144-62013 although it is currently out of stock. THey also are used in the Rapido Trains passenger cars for turning the lights on and off; they may be able to sell you some as spares.
Rapido has a new passenger car that uses a similar switch. They even supply a “magic wand” to operate the lights with. The reed switches are hard to find. The last time I bought any was 15 years ago and it was from a surplus electronics place that is no longer in business. Before everything went solid state, reed relays and switches were common.
There are two types of reed switches. A reed switch only makes contact while the magnet is over the switch, a latching reed switch stays in position until the nagnet passes over it again. I bought my latching reed switches from miniatronics some time ago. You may try Micro Mark.
I done a similar project. I would suggest that you mount the battery on the floor of the car to lower the center of gravity, also, if possible, try and find a way to defuse the light so that you can’t see the bulbs, just the light given off. Good luck.
I saw an article in Model Railroader (early '60s) that made latching reed contacts out of non-latching reed contacts by positioning a small “bias” magnet near the contact. The bias magnet was placed close enough to not throw the contact, but keep it in place once thrown. The bias magnet has the added benefit of increasing the reed contact’s sensitivity. This means the contact can be actuated at a greater distance by a given strength magnet.
Again, I have not tried this myself, but offer it as a suggestion for experimentation.
I would suggest you use golden white LEDs instead of lightbulbs - you’d be able to use smaller “watch” type batteries and they would last longer as well. Richmond Controls http://www.richmondcontrols.com/ is a good source, they’ve got a bunch of other great lighting products as well.