[Erik M]

I hope you don't mind if this is split of into a separate topic...
QUOTE (sealevel @ 28 Nov 2011, 21:04) <{POST_SNAPBACK}>I am planning to use that circuit to cut power to the pit exit so there would not be any collisions when leaving the pits.

I thought it could also be used to cut the signal/power to the solenoid for the lane change and possibly send power to the opposite solenoid (for SSD which does not move without a signal) to force a parallel run (since there are both NC for normally closed and NO for normally open points on the relay).

Maybe you or someone else can advise if infra red or opto sensors can do the same job as reed switches, to close a circuit when light is present and not when not present (I don't car what the light signal is).
First of all, you don't drive things with the IR sensor. It's not meant to carry that kind of load. It only carry signals, as down at below 2mA. And that isn't much...
But coupled with voltage comparators the sky's the limit on what can be done.

When there's If and OR and XOR and AND and NOT and, especially, WHEN and UNTIL then simple switches aren't enough.
But there's a short cut, using a computer and write a program to handle it...
...or start looking into OP's like voltage comparators, sample and hold etc.

But in this case it could maybe suffice with a barrier and the sometimes excellent LM311 single comparator.

 

[sealevel]

Hi Erik,
Like we were discussing...
My plan is to TRY and use a 12v circuit from the railroad folks to kill power to small stretch of "pit out" track using reed switches.
The first switch detects cars in the inside lane arriving near pit out, the second after they have cleared pit out.
The circuit is one used by model RR folks to prevent trains from entering a "block" when it is occupied and comes with a bonus of red and green lights.... perfect for the end of the pit lane.

Anyway.... unable to test this yet, even though it has been on my shelf for months...
When I do try it out, I will report back.

In the meantime... what do you have in mind?

Cheers!

 

[1 32 slotter]

Yet one more reason I love this forum. Good idea. Will be implementing this once figured out how.

 

[Mr_DJT]

Going to keep any eye on this 1

 

[Erik M]

Give me a moment and I'll solve it for you. I hope...

 

[Erik M]

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Something like this is one way to do it.

The IR-LED make a barrier with the IR-transistor.
With no cars racing by the IR-transistor have low resistor value. Thus the LM350 adjustable voltage regulator give full power to the pit lane (which includes giving it lower than the race track, simulating speed limit etc).
When a car race by the resistance rocket and the voltage drop.

I haven't tested this, but it looks neat with both blue light and speed limit in one package.
A yes, I haven't added a blue light to it. I'm off for an afternoon nap...

 

[sealevel]

I can get speed limits in the pit lane via SSDC and Pit-Pro for SSD.
So only looking at controlling the pit lane exit.

BTW, there is quite a discussion over powering exit flippers AND some discussion about collision avoidance on this thread (link) for Scalextric.

I have a Velleman MK111 kit and still looking at how to use it for the anti-collision application.

Cheers!

 

[Erik M]

You could use the 555 Timer circuit, but it's not really suitable for this. It's a IC for timed pulse, not for timed impulse.

 

[sealevel]

Sorry for confusing you....
I am planning to use the model RR power interrupt in my previous link to cut power on pit out and show red light, then power back on, with green light for pit lane only.

As for the MK111 unit, it was referred to in the other thread I mentioned (see post #7) as a candidate for modification for the anti-collision circuit (with some undefined mods, of course).

Otherwise, I am thinking of using the RR power interrupt circuit to cut the power to the lane changing sensor. Just have not figured out how to "auto-set" the LC to straight ahead after cutting the power to the sensor so all is straight ahead. Maybe tap into the "other" lane sensor on the CLC to trigger the solenoid? Ahh... another idea that will have to wait for testing..... in the distant future.

So here is a question someone can answer...

If a relay has both NC (normally closed) and NO (normally open) contacts to open or close a circuit, could one be connected to a LC sensor to "cut the input to change" while connecting the other to "close the circuit to stay straight" at the same time? This would effective switch the controlling sensor from that in the lane wishing to change (cut the circuit for the sensor) to the lane wishing it NOT to change (close the circuit to that sensor) and transfer control from one lane to the other. Will this work?

Cheers!

 

[sealevel]

Any comments on my question above about using BOTH the NO and NC terminals on a relay to cut power to one solenoid and to "set" the flipper using the other solenoid?

Cheers!

 

[Erik M]

You only need to block the "change" solenoid, IIUC. The "straight" solenoid comes on automatically, right?

 

[sealevel]

Not on Scalextric.
No "power" no charge to the solenoid, no movement of the flipper.

The model RR unit I am looking at (link) interrupts the power to a "circuit" (say one section of one rail of the pit exit) when the first reed switch is tripped in the main straight and restores power when the second reed switch is tripped after the pit exit on the main straight. It also lights up RED or GREEN lights (after all it is for model RR layouts) which is the same as the pit exit lights.

To use this on CLCs or XLCs, it could be (by my way of thinking) to interrupt the signal to a solenoid. My question is, if we interrupt the power to the "switch" solenoid (by switching from the NC to the NO terminal) can we also close a circuit to the "don't switch" solenoid so that the lane to which a car would switch would control the access from the other lane (i.e. inner lane of an OUT to IN CLC would control the outer lane access to the CLC between the reed switch points). In effect the relay transfers control of the LC from a switching solenoid to a straight ahead solenoid, then use the existing sensors to trigger the straight ahead solenoid.

I hope this makes sense.
Any comments?

As someone mentioned a couple of years ago, the solutions for anti-collision are probably sitting the model RR area waiting for an alternate application.

Cheers!

 

[Erik M]

There's three leads on the SSD point.
One Ground, GP (but as we're talking of the Land of Lucas that's probably positive...).
One Power to the Change solenoid, CS.
One Power to the Straight solenoid, SS.

You clip the CS lead only, not the Ground lead. Thus SS still is active.

 

[Erik M]

And your question would be answered with a yes.

If the SS need a "neutral input", as in "I want to go nowhere special", then you would need to do just that.
That is, if the point is the CS position and the next car need go straight, then the SS must act on both switch and straight order with a straight response. Else a switch order would end up with the point staying in the switch position that it shouldn't.

Splendid bit of extra information... Back to the blue prints for me then...

 

[sealevel]

But to ensure that the "inside" lane sends a go straight signal, would not that solenoid circuit need to close when the "outer" lane (change solenoid) is opened? I am talking CLCs here.

For the XLC both sides are active already so just need to cut the power to the change solenoid, right?

Cheers!

PS my track pieces are still in storage so cannot look at the electronics right now. Hopefully I will be able to sneak a peak before New Year's!

 

[Erik M]

If the previous car changed, then the point's left for change, right?

If CS power is cut when the next car comes along and press it's CB there will be no signal to power the SS. Thus the car will change lane, exactly when it wasn't supposed to.

Both CB and not CB must result as if a signal to the SS.

The combined NO/NC reed switch would accommodate this.
The common reed lead on the CS power lead and the NC to the CS; this is the cut lead to the CS.
The NO is then connected to the SS; there's no lead cut here, mind you. But just to be sure I'd put a rectifier diode there too.

CS ~ change solenoid
CB ~ change button
SS ~ straight solenoid

 

[sealevel]

Thanks Eric,
On my "to do" list.

Now back to finishing Christmas cards and annual "letter"...

Cheers!

 

[sealevel]

I forgot to ask...

Any suggestions on the rectifier diode?

I presume it should prevent back current equal to what the forward current is, correct? If you have any suggestions, they would be appreciated as I am getting back into electronics after being away from it for some 35 years.

I also found some specs on the relay that say the operating time is 8 msec and the release time is 5 msec.
That should be quick enough for the speed of the cars to allow power to be cut then returned to the change solenoid.

Cheers!