Wiring up reed switches

P

playmofire

Registered
Country flag
I'm planning a layout which will eventually use IR-dots for operating an auto-shuttle and station stops.

However, this summer I am setting up a layout on a temporary basis and intend to use reed switches. LGB or Piko ones would have been the easiest to use I imagine, but at those prices buying 10 for single use is out of the question, so I have bought 10 Gaugemaster reed switches.

When ti comes to wiring them up, presumably one end is wired to a power supply and the other to the appropriate connection on the station stop or shuttle, i.e. the slow decelerate terminal or the brake terminal.

Does it matter which en of the switch is connected to which terminal?
 
playmofire said:
I'm planning a layout which will eventually use IR-dots for operating an auto-shuttle and station stops.

However, this summer I am setting up a layout on a temporary basis and intend to use reed switches. LGB or Piko ones would have been the easiest to use I imagine, but at those prices buying 10 for single use is out of the question, so I have bought 10 Gaugemaster reed switches.

When ti comes to wiring them up, presumably one end is wired to a power supply and the other to the appropriate connection on the station stop or shuttle, i.e. the slow decelerate terminal or the brake terminal.

Does it matter which en of the switch is connected to which terminal?
Click to expand...

Gordon,

LGB and PIKO I understand as I use them and they work the same: there is a single Ac feed into a reed (let's call this black) which then goes to two diodes. These transform the Ac into half wave DC + or -. (Let's call that output Orange)

PIKO and LGB point motors work off half wave

SO

If you connect the other Ac wire from the transformer (let's call that white) to the point motor it can switch.

If you connect two orange wires - one bring the + output from a reed and the other bringing the - output from another reed the point motor can be made to switch both ways.....

However I have no knowledge of the Gaugemaster ones. Do they have diodes? If so they will be direct substitutes for PIKO or LGB ones, but if not, and that is what you need to switch, you will have to add your own diodes to give the appropriate have wave output from each reed.

Re-reading your text I see you seem to be using some kind of non LGB/PIKO module. I guess that just needs a simple full AC output from plain non diode equipped reeds, so not having LGB or PIKO half-wave fear coukd well be an asset.

Just connect one output terminal from the transformer to the module and the other to the input of the two reeds. Then connect their outputs to the module as appropriate. When a magnet passes over the reed it will complete the circuit and trigger whatever the chosen function is.

James
 
Last edited:
Are we talking reed switches or momentary switches here James ? I am looking into the same thing to actuate sounds on a card.

I have a wiring diagram and as I understand it a "reed" is triggered by a magnetic field, i.e. a magnet fixed to track, or at some point where its magnetic field will actuare the mounted switch. Not the polarity of a current. No mention of diodes in my manual. Just two terminals on a board feeding into the switch. Which way round it is wireed would seem to be immaterial as it is a simple on/off trigger. I might be very wrong but am keen to find out. Max
 
I'm not using the reeds for point changing, James, only to send a signal to, for example, the auto shuttle to decelerate the train as it approaches the end of the line, so I'm only dealing with a single reed at a time. (A second reed switch further down the track will be triggered to stop the train just short of the buffers.)

Here's what the reed switches look like: (although they are much smaller than that!)

http://www.gaugemaster.com/item_details.asp?code=GM99
 
The reed is just a switch, no polarity on them.
 
Thanks Guys,

Apologies for going off on the wrong tac!

Gordon, I assume that the module will need a power supply, but I guess each reed has two terminals allocated to it on the module?

Just mount the reed where you want and run the two wires to it.

(Modules are quite different to point or signal changing where you would power the reed directly off the power supply).

As has been said, (and your link helpfully shows), these reeds are non polarised, so it makes no difference which way round they go.

You will need magnets under your locos to trigger the reeds and some way of mounting the reed in the centre of the track so that it is high up almost flush with the rail heads.

Massoth do some nice magnets that are slightly cheaper than the LGB ones.

Good luck!

James's
 
dutchelm said:
The reed is just a switch, no polarity on them.
Click to expand...
As Mike says it does not matter which way round you wire them. Only issue I have ever found is getting them to work with a moving train long enough to fire what you want to be fired. Best solution is the LGB Magnet as it is nice and long and will be certain to make the reed contact to fire off your relevant action.
EDIT
James advice is also spot on entered as I was typing.
 
Likewise, thanks for the information James, Mike and John. Can you reccomend a good source of small reed switches, as an alternative to Gaugemastet, I can mount under a tender ? Max
 
So long since I bought or needed any, would have thought that a Google search would come up with plenty of alternatives. GM can be very expensive for almost anything.
 
Thanks for all the information everyone.

The reed switches came with five magnets and I hopefully these will do the job. I don't run my trains fast (I aim for scale speeds as for a rather rub down branch line).

Securing the reed switch in place between the rails is giving me pause for thought. I'm thinking of sliding it into a piece of square Plastruct tube and then glueing this to a piece of thick plastic strip cut to fit between the sleepers.
 
idlemarvel said:
If you can find a maplins still open, they do cheap reed switches, on-off and on-on (SPDT)
https://www.maplin.co.uk/c/STEM-com...nents/component-switches/reed-sensor-switches
Click to expand...
Was a little reluctant to suggets that option as they will are already not around for us all, a very sad loss to the High Street. There is or was another High Street alternative who's name entirely escapes me at the moment. They have or had branches in Watford and Croydon plus many other retail locations. They do do varying bits of electronics but not sure if reed switches were on their shelves.
 
I do use reeds a lot both for LGB and in HO to control level crossings for slot cars! Normally they are mounted lengthways along the track, so the length doesn't matter.

From time to time I have to repair LGB reeds, (especially the nasty horrid and over priced modern 17100 version) and these need a slightly smaller reed than those Gaugemaster ones, but usually searching on Google or E bay produces a hit!

Good luck!

James
 
James Day said:
I do use reeds a lot both for LGB and in HO to control level crossings for slot cars! Normally they are mounted lengthways along the track, so the length doesn't matter.

From time to time I have to repair LGB reeds, (especially the nasty horrid and over priced modern 17100 version) and these need a slightly smaller reed than those Gaugemaster ones, but usually searching on Google or E bay produces a hit!

Good luck!

James
Click to expand...

So along the track rather than across the track? It has occurred to me that in my copy of The Big Train Book (circa 1984/85, £10 a couple of years ago at a little second bookshop in Robin Hood's Bay) the 17000 reed switch is virtually a reed switch fitted on to one of the LGB cable tidies. I have some of those and so was wondering about making these the basis for mounting the reed switches. However, they go crosswise.
 
A little practical advice on using reeds:

The glass envelope is quite delicate. Worth protecting them, or buying already encased units..

Hold the wire in pliers, and bend the wire with your fingers OUTSIDE the pliers from the reed. - Or else you are likely to break the glass envelope.

Don't get them too hot close to the envelope.. The heat can reduce the magnetism in the reeds. - You do have to get them hot for some-time, but it depends on your iron and soldering ability.
 
Gordon,

Along or accross doesn't matter, but obviously with 00/H0 there is just over a third of the width of 1/G, so as the Baroness once said "There is no alternative!"

Yes, you could use your LGB 1700 units to operate your module, but only if you link the two half wave outputs of them together.

I did this when we exhibited the LGB with the Carrera 1/24 scale slot cars: the module that made the cars stop at the level crossing had been made many years ago to use with 00/HO so was not geared up for a half wave input. I just used a chocolate block to link the two side outputs of the 1700 together and it worked fine.

Your module should be able to be operated in the same way.

Again once you link the two 1700 outputs it won't matter which way round you wire the reeds.

James
 
Last edited:
So..... can reed switches be used with DC?
 
trammayo said:
So..... can reed switches be used with DC?
Click to expand...

I guess it is all down to the current:
I recall talking to the guys at AMR Electronics when I first stated using their reeds to operate the Tri-ang Relays to control my Minic Motorways.

They told me I was overloading the reeds and they would quickly burn out.

They didn't, (ok they did once or twice), but I guess most applications don't carry the full switching power through the reed, as I did, or as they do with LGB, so they last longer.

On modules like Gordon's, my guess is they the voltage and current going through the reed is low, so it won't matter if it is DC or AC.

James
 
trammayo said:
So..... can reed switches be used with DC?
Click to expand...
Yes they are just mechanical switches completing a circuit, switched by a magnet pulling a thin strip of metal inside the glass tube one way, which will spring back the other way when the magnet is removed. They can be on/off or on/on. If you have or have seen an LGB RhB colour signal they have a reed switch inside the mast which is used to switch the red or green light, and they can take AC or DC or even DCC current for the light bulbs in the signal mast head.
 
i lovve it! another excuse for old pics!

you see an LGB reed (old model) and my copies.
i have no idea, what the roundish things paralel to the reed are. LGB has it - i have it too. (without them the reeds have a shorter lifespan)
the diodes i have apart, that way it is easier to change their direction.

reeds.JPG


how i connect them. (the round points represent reeds)

reedsteuerung1.JPG

at the left you see, how i build the reeds (korm's model 2)

replacements.JPG



reedschalter.JPG


still not bored?
ok, going on:

reeds-simple-passing.JPG


reeds-polarity-switch.JPG


and, last and least, the LGB manual, how to connect reeds. (search yourself in chapter "taking control")

http://kormsen.info/lgb-manual.pdf
 
You must log in or register to reply here.
Back
Top