Solenoid driver

[earckens]

Ultimately with one pushbutton per turnout?

 

[chemelec]

Well the way it is, I assume the switches are set to default to the LEFT.
So even if the 555 Pulse activates All the Solenoids, Only the ones you set RIGHT will actually change tracks.
It Shouldn't be a Problem, but just a waste of power.

 

[alec_t]

I'm late to the party, but have you considered this arrangement?

 

[earckens]

Actually there is no default setting, a switch can be either left or right. This would mean every time the pushbutton is pressed every turnout (one of its 2 solenoids) will get a pulse. And that is not ok.
Solution: get one (double pole) pushbutton per turnout, in series with the SPDT, and all pushbuttons (double pole) also in parallel to your circuit?

 

[earckens]

I'm late to the party, but have you considered this arrangement?

alec_t, what is the box at the left of the circuit?

 

[chemelec]

Well according to your drawing, it shows switches set left.
Implying that this would keep the train on the Main Line.
And Pushing one switch Right, would put it on a Side Track for that solenoid.

 

[chemelec]

Alex T is using a Center Off Switch.

 

[earckens]

Well according to your drawing, it shows switches set left.
Implying that this would keep the train on the Main Line.
And Pushing one switch Right, would put it on a Side Track for that solenoid.

Hi chemelec, there is no priority or preferred turnout setting.
So I start to believe the only way to assure power goes to only one solenoid is to provide a double pole push button per turnout: one pole to direct the current to the solenoid, one pole to be placed over your circuit, in parallel with all other pushbuttons. Right?

 

[earckens]

Alex T is using a Center Off Switch.

Here we go again with the capacitor discharge circuit, and this is where we want to get away from. No alec_t, unless I misunderstand your proposal I think this is what we have been backing away from.

 

[chemelec]

If you use a DPDT Switch, One side of the switch could be used for the Push Button, and the Other side for the relay.
Since each Solenoid is already Grounded on one end.

 

[chemelec]

I have to go out in a few Minutes, so I won't be back here till TOMORROW.

 

[earckens]

If you use a DPDT Switch, One side of the switch could be used for the Push Button, and the Other side for the relay.
Since each Solenoid is already Grounded on one end.

One side for the relay: ok, but the other side to the pushbutton, and now how do you arrange for current to go only to the one turnout you want to activate?

 

[earckens]

If you use a DPDT Switch, One side of the switch could be used for the Push Button, and the Other side for the relay.
Since each Solenoid is already Grounded on one end.

ok, I will wait for you; have a good day!

 

[alec_t]

what is the box at the left of the circuit?

It's the two solenoids of a turnout.

Alex T is using a Center Off Switch.

No. the switch is a normal SPDT one (ON-ON).

 

[spec]

Man, spec. I am so jealous.

Yes it was great fun.

Got a Lionel as a Christmas gift in the mid-fifties. Coolest gift ever, even if only a single, circular track. Puffed "smoke"! My Dad built a mountain range with wooden trestles for it in our basement. Although, do be honest, the locomotive unit spent more time at the repair shop then on the track.

I can't remember not having a train set, I think it was Hornby. And over the years it grew and grew.

You need to find that sucker... .

Long gone, I'm afraid.

 

[earckens]

It's the two solenoids of a turnout.

Interesting. There only is capacitor discharge (or charge) current through the solenoid that is selected.
But now we back away from chemelec's proposal of using a MOSFET switch.

What definitely is required is a SPDT or DPDT switch (ON-ON) per turnout and a pushbutton (SP or DP) switch -probably per turnout?-.

Now marry this with chemelec's MOSFET circuit, ensure activation current only goes to the required solenoid (and not to the whole bunch every time the pushbutton is pressed), make sure the turnout switch shows visual indication of switch position (ON-ON double throw switch)... and possibly insert alec_t's capacitive discharge circuit (although I doubt the latter is possible/feasible/desirable).

I hope we get this sorted out..

 

[alec_t]

alec_t's capacitive discharge circuit

It's not mine. It was published in Radio Modeller.

 

[chemelec]

MY Suggestion is Here:

 

[earckens]

Thank you Chemelec. But now if multiple turnouts have to be activated I should place their respective DPDT ON-ON switches in parallel, right? Now this results in power going to one solenoid per turnout.
Would using double pole pushbuttons not be an alternative (see my drawing proposal)?

 

[KeepItSimpleStupid]

What I think I would do is to use 24 VDC relays You can use a 4PDT relay such as: https://www.mouser.com/ProductDetail/Omron-Automation-and-Safety/MY4ZN-DC24-S The 4PDT relay likely has less current draw than two DPDT relays. So, pick the quiescent state as the stet it's likely in most often to conserve power. Multiple relays can be connected in parallel and just activated by a simple SPST switch which has constant 24 VDC power.

I'd actually put diodes across the coil close to the coil on every coil: Solenoids and relays.

The number of solenoids that the system can drive depend on the MOSFET or multiple MOSFETS can be used with the 100 ohm resistors.
DPDT might be better. You can use steering diodes to activate multiple combinations of say 4 SPST switches and they won't interact. It's called WIRE_OR.

An easy way to understand this is to put one side of the relay at +12. Whatever relays you want activated, connect a diode to those relays such that the bands are connected together and through a switch to ground. So, maybe you could have a switch with OFF.

Now it's getting down to SPST contacts when I look it over. So, you can have a SPDT switch that operates two (gizmos) One position that activates the LEFT solenoid and one that activates the right solenoid, and the other position is vice versa with center off to save power. If you used DPDT latching relays, one could be the state. This is a bit more complex to do, but it might be worth it because you can have signals. The relays latch magnetically and can be dual coil.

This post probably reads like mush and I really need to think about it. A lot doesn't make sense because I'm not 100% functional. I think better yet, you can use the dual coil latching relays on the solenoids to get position info. You may have that another way.

I didn't realize that the DPDT switch is a (ON) -OFF - (ON) switch or momentary. TRIGGER is just a label.

You still should be able to diode OR the solenoids and/or relays controlling them an any combination you want, so that multiple gismos operate at the same time. If status is not already implemented, a dual coil latching relay or micro switch could work.

Sorry that this post is so convoluted.

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In any event plug in relays and DIN real construction is the normal way to go. Terminal blocks are used for outside world connections.