Wanted to put a magnetic reed switch like the ones that Kato used on the Easy Peeze pass light kit in a N scale car. Wave a mag over it …light on, wave it again …light off. But am having a tough time finding them anybody have a source for them…Thanks Much
All Electronics has them, but they are not the ones you need.
You should check with Mouser, I got some there that worked for what I wanted, but they only pull in the presence of the magnet. I want to turn the lights off, I put the magnet on top of the train. I want them on, I take it away.
Are you using DCC with power on all the time? Then the lights will be on all of the time.
Are you using battery powered car lights? I tried that but was not happy with what I built.
What I am doing now is to use a rectifier, a regulator, capacitors and LEDs The lights will stay on after the train stops, but then after a while the capacitors will be fully discharged and the lights will be off.
ROAR
I am also interested in this, and a resource. So if anybody knows a resource I will be watching. LION’s response may be interesting in some way, but it has nothing to do with the question, pretty much as usual. LION needs to ROAR in time out again!!!
The keyword to search for is “latching.” That’s the industry term for something that stays where you put it until you tell it to go back the other way. As I recall, though, I had a hard time finding these, too.
But wait, we’re missing the random photo of a cat? The would fully explain his response.
ROOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOAAAAAAAAAAAAAAAAAAAAAAAAARHHHHHHHHH!!!
Actually I forgot. I have a couple of Walthers P2K locomotives that have the QSI decoder. And it has a reed switch in it to reset the decoder.
Try to contact Walthers?
Those, however, are momentary, non-latching switches. MIniatronics carries those, and they’re very inexpensive. But, they won’t do the job that the OP wants.
Gentlemen…is this what we are looking for?
http://www.meder.com/switch_ksk-1e66_us.html?&tx_jppageteaser_pi1[backId=2864:550:0]
p.s…I set this to open in a separate window, I hope it works that way! I find it annoying personally to click on something that takes me off the original page.
Rapido also uses them in there coaches. They work well. I want to rig one of their magnets down from a signal arch and route the train on the track that passes under it to turn them on or off as the train leaves or enters the yard or station. You don’t have to touch the coach to turn them on, just get within about a quarter inch or so.
Email Rapido, they may be able to point you in the right direction of where you can buy them.
Brent[C):-)]
The animal control officer keeps deleting my cats. If you want cats click the link in my signature. [:-,]
St Francis
I can’t get your posted link to work, and I’m not sure how to fix it. I know others have done this before when a link won’t work. Perhaps someone can step in to save the day.
Dave
This link should work.
From what I could gather from the documentation & data sheets a magnetic coil is required in addition to the Reed switch with latching function.
Now it works Dave…I didn’t originally use the little chain link deal at the top to insert the website. Geez!
But I still don’t know if the switch is what we’re looking for. The post below mentions that it needs a coil magnet, but I’m a little embarrassed to say I don’t know what that means.
If I’m reading the .pdf file that covers the latching function, you still need a secondary magnet in association–one that’s not strong enough to close the switch on its own, but can hold it closed after a magnet of the same polarity passes over. When a magnet of opposite polarity passes over, it separates it–if I’m reading correctly (no gaurantees that I am).
I think for purposes of turning lights on and off, you’d perhaps want to use a “normal” magnetic reed switch in conjunction with a latching relay. This is a relay that when energized with a pulse of electricity, throws one way, then when energized with a pulse again, throws itself back the other way. that would allow you to use a magnet to turn the lights on and off. The magnet would momentarilty close the circuit to energize the relay coil. The output of the relay would be used to route power from the track to the lights.
Probably no trouble to hook that up in HO scale, but fitting a relay inside an N-scale coach may be a bit problematic.
Later,
K
You can make any magnetic reed switch latching by placing a weak magnet near it. It needs to be placed such that it won’t cause the reed to operate by itself. Placing a strong magnet near it will cause it to operate and the weak magnet (if in the right place) will hold it in and cause the latching. Turning the strong magnet in the opposite direction will cancel the magnetic field and the reed will release. It requires a little fiddling to get the right strength magnet in the right place. It’s best to do this trial and error process at the workbench with the lights connected so you can tell if the reed is operated or released.
cheers
I was buying Meder glass tube latching reeds fron Demar until Meder decided to wholesale them in large lots only - now Demar does not sell them, nor anyone else I could find. However, the Meder MK06-10-E is the same thing with an added plastic housing. They don’t require an external magnet or coil. I was able to get ten at $4 each, double the price of the unhoused version, from, I seem to remember, Digikey. Hal
Yes, Digikey has them. Looks like the price is $7+ for one though.
The E at the end designates the latching function. These do not require a magnet to assist in closing the circuit, but a two pole magnet is required to cycle them on and off.
I’ve been looking for something like this too. The price however, does not make me feel warm and fuzzy. I think I could figure out a magnetically operated, transistorized, latching switch, for less than $7.
Thanks for pointing me in the right direction to find these all the same!
If the lights are being powered by a battery or some other continuous power supply (absolutely no drop outs), then yes, a basic standard reed switch could be used as the trigger to a simple transistor flip-flop circuit so that the lights would go on the first time you bring the magnet near, and the lights would go off if you brought the magnet near again. The transistor portion of the circuit would always be drawing power though, even with the lights off, so it wouldn’t last forever in storage, you’d have to remove the batteries. Since the lights, even if using LEDs, would be the lion’s share of the load, it would be better than not turning off the lights.
–Randy
Yes it sounds like I am looking for the latching ones, the same that are in the Rapido passinger car lighting units
Randy,
Thanks for joining this discussion. I’ve linked a schematic below. In the circuit transistors are used to latch a momentary push button. The text mentions the capacitor charging when the circuit is powered up but the transistors don’t “turn on” until the momentary contacts are closed.
Are the transistors drawing power in the off state with this circuit? Once the cap charges fully will it continue to consume power if the momentary contacts are not closed, turning on the transistors?
Thanks.
JS