Form E

I didn’t know about the form E switches.  Always good to have another tool to hit a problem with.  Nice article.

Strong Enough?

I suspect these are NOT strong enough to throw Peco turnouts with their stock springs in place?

What is strong ??

Hi Brian,

It's not  April 1 yet ! But thanks for making me laugh with your comment.

Anyway - it's not a stupid question for actually you CAN trow a turnout automatic with a Reed switch in a very simple way !

Let them laugh !

Success & greetings, Filip

Strong enough?

I’m not quite sure what you mean Brian.  Reed switches typically have a fairly low current rating, so I wouldn’t use them to directly control a twin coil switch machine if that’s what you’re referring to.

The beauty of...

...Reed switches is it's simplicity in use and low cost.

Think of automatic signal control without the costly electronics and all the 'modules' with gold prices. Automatic turnout control for Solenoids -- just to add a few to the article on how to light it up.

Ask grand father and he will tell you how they ran their model railroads ( not even soooo longggg ago).... we seem to forget "SIMPLICITY" (as with so many aspects in our 'society' )

To think about...and there is more about these little REED family. A good start with this article. Thanks for sharing !

Filip

(Incorporating automatic turnout control and signal system with REEDS on the ANNELISVILLE RR - well... busy with the development of it)

Wrong Image?

Perhaps I conjured up the wrong image of a reed switch? I was picturing a magnetically controlled micro switch,.... and wondering how that might mechanical throw a turnout cross bar. (did I have the correct wording there?)

PS: Yes I now see I had the wrong image in my mind....ha....ha
https://en.wikipedia.org/wiki/Reed_switch

Reed Switches

Hi Brian, all,

Reed switches switch (as in control) electrical current when there is a magnet near them. The moving bits are inside the reed switches and CANNOT move anything physically external to the reed switch itself. You use the reed switch to control whatever is providing the shove to move stuff, like servos, relays, solenoids etc. 

A switch is a switch(electrical), but not that type of switch (turnout). I hope that this helps,

Circuits or how to's ?

Hi 

I don't want to sound like a dummy but I am a novice, would you do an article with a few examples with a how to thanks.

Regards

Michael 

"How to" for a reed switch

Michael,

Here's a picture of a reed switch I set up on a rotary plow that I motorized.

If you're interested in how it was done follow the link to my web site.

http://www.kingstonemodelworks.com/RotaryPlow.html

Bernd

Re Circuits or how to's

Hi Michael,

for an example of how non-latching (Form A) reed switches can be used to control automation on a layout, have a look at 

" Decoupling 2" on my Corrimal Colliery Incline thread that explains how non-latching reed switches were used to control automatic hands-off movement and tipping of coal skips in the tipple at the foot of the incline. This post explains what each of the 5 reed switches did. 

If you are going to use reed switches as inputs to an Arduino Dr Geoff Bunza in " Re: Wiring Problems" shows the correct way to wire in a reed switch (here S1). In " Re: A number of issues" covers defining and using the internal pull-up resistors to set the state of the reed switch for programming the Arduino. 

The Form E latching reed switches are useful for lighting projects as they turn on if they are off or tun off if they are on. You should be able to wire then directly in between your power source and your lights on a lighting project. 

For a large building you could have multiple zone lighting with each zone comprising simply of a wire to one end of the latching reed switch from the power source, the wire from other end of the latching reed switch to the light(s) in that zone and a return wire back to the power source. No Arduino needed, but you need to know where the reed switches are so that you know where to swipe with your magic magnetic wand. 

There's no magic in this type of a circuit - It's a basic "battery> switch> light> return wire to battery" circuit with the magnetic latching reed switch as the switch. Try a simple version out in the open that doesn't move before you go hiding it in a caboose or passenger car. I think you'll like it,    

Oink, Oink, Oink!

A friend of mine received a greeting card which, when opened, oinked at him like a pig.  After laughing, he used his modeling savvy to remove the circuit and speaker.  He installed them in a stock car and attached them to a reed switch.  Then he mounted a magnet at the stock pen, and again at the butcher shop.  Now, when you spot a car to be loaded, the pigs oink.  They oink again when they are unloaded at the butchers, and also at a couple points along the main line.  The volume is quiet, but it surprises operators and always gets a smile.

Reed switches Form E

I'm working a longer time already with these reed switches, especially for switching lighting of passenger cars without using a function decoder.
In video a sample of a battery powered train end light without each electronic, simple and cheap. Using this system on a DCC layout is more simple yet, only the resistor for lighting the cars by LEDs musst be enlarged.

Three circuits in one car

I discovered latching reed switches 15 years ago thanks to Rapido's Easy Peasy lighting system.  I found a source for them, though they were much bigger than Rapido's, and used them to control lights in a Walthers heavyweight observation car that I painted in Crescent Limited colors for a friend.  It was before there was the plethora of LED options we now have, so it was all incandescent lights run off of on-board batteries.  The lights on the platforms, the interior, and the markers and tail sign, were all on independent circuits with the three switches imbedded in the roof.  Nowadays, I use LEDs and they just come on when the power is on.  But I still have about a dozen of the switches, and you’ve given me some ideas on what I can do with them.  Thanks!

Nice to see Reed switches again

Standex-Meyer MK24 is not a latching switch

These are made in Form A, B and C but I could find no indication of a latching version in this diminutive package. The article claims it was used in latching form for the caboose lighting application but this seems unlikely unless it included some additional on board electronics to latch alternating states.

If there is indeed a latching version, a corrected link should be posted and the article amended appropriately.

The small size looks appealing for other applications, including using form B (NC) as a disconnect mechanism for keep alives when working with decoders on a programming track where the presence of a keep alive can often interfere with programming operations.

MK24 no longer available as type E

Home made latching reed relais question

Hi,

in the above shopping list is a link to an article about home made latching reed relais. I like the idea and the link explains it very nicely.

However, I've been wondering whether it is possible to wrap a few turns of wire around the reed switch and make it self-holding? I've used this concept in the past with mechanical relais - one of the contacts is used to provide power to the relais and to keep it "on" in a "normally-off" relais. Interrupt the holding circuit to drop the relais.

I could imagine using this concept for a grade crossing. When the train passes the "on" location, a reed relais is activated and is kept "on" with a holding coil. After the train passes the "off" location, the holding circuit is interrupted by a second reed relais (this one "normally-on"). Simple animation with (almost) no logic circuit at all...

The same could be used for animation of things inside a car or loco, too.

Would that be possible?

Have fun!

Home made latching relay

https://www.kingstonemodelworks.com/RotaryPlow.html

Bernd

Update on the tiniest latching reed switches

Here's the latest on the tiniest reed switches we can find ...

 

Shown with HO track and an HO truck. The MK24 is a normally closed non-latching reed switch, and the KSK-1E66 is the smallest latching reed switch we can find. Note the tiny magnet on the KSK, proof that it's a type E latching reed switch.

The KSK is still plenty small for HO, and it also should work in N and Z, but it's not as size convenient as the MK24 package, which no longer comes in the type E format.

Off the wall thought

Hi all,

Tonight's off the wall thought is:

If you can't get latching magnetic reed switches, use a non-latching reed switch to control a latching relay.

I did so, way back in the late-1970's to control six signals. This is a slightly different application of reed switches than that discussed in the MRH article.

The signals were a red/green grain-of-rice filament type in N scale. There were actually 2 separate circuits, each controlling 3 signals.  The idea was relatively simple but the execution got a little complex, with a complicated diode matrix to prevent unwanted results. 

The idea - If I used a (non-latching) reed switch in the middle of the track near the signal mast, then by placing a magnet on the wagon behind the locomotive:

• the loco always "saw a green" when approaching a signal
• the signal "dropped to danger" (red) after the cab of the loco had passed the signal
• when the signal dropped to red, it changed the other signal on the first latching relay to green, so that when the loco got to near that other signal, the locomotive always saw a green
• the signals were set up for one direction of travel only, so, provided the direction of the train didn't change, the signals would automatically display the "correct" green aspect to any approaching train.  

Where it got complicated - 2 of the 3 signals on each circuit protected either the entrance or the exit to a loop. So a single output from either reed switch beside these 2 signal masts at either the entrance or exit of the loop had only one output - change the far signal to green, But when the loco triggered the reed switch at the far signal, there were 2 possible signal that could go to green but only one should go to green - the signal for the selected route. The signal for the non-selected route had to remain red. 

An Arduino or similar would have made the wiring a whole lot less complicated. but they were a long way off in the future when this coffee table layout under glass was built. But even that KSK latching reed switch would have simplified things a lot had it of been available in the late 1970's

Regular "latching reed switch" service has resumed,  

Reed Switch uses

Hey guys, we are using the latching type reed switches to kill the sound in our DCC Sound equipped locos. 

We were tired of hearing the unrealistic sounds of locos when running inside our tunnels. Rather than using the mute function on the throttles, we installed a latching type reed switch in line with the speaker on the loco. With hidden magnets in the track our locos now go silent just after entering the tunnel and then resume their sound just before exiting the tunnel. We did this mainly for our multi-turn helix so it doesn't sound unrealistic while the trains are taking their 2 minute run up or down the helix.

Cheers from the Spring Creek Railway in On30, Montrose, CO