3 aspect model RR signalling help plse

[angie1199]

Good God! I know the pound and dollar are in the tank but my All Electronics store still has them for much less. Or maybe it'sbecause I use 24 volt relays and the higher the volts the higher the rebate .

That's why the UK and USA are not manufacturing much anymore and we all import from the middle/far east. The Unions kept striking for more money, that put up prices for products, everyone else striked for more money to buy the more expensive products, and so on, Vicious circle till companies decided to get stuff made abroad for cheap prices and import, and now the UK has 2.5 million unemployed. And yet no one sees the logic that follows!

BUT before you do that hook the base of your 'detect' driver transistor directly to the Twin-T collectors. (no base resistor) Also up the Twin-T collector resistor to 3.9K. Your signal driver should work backwards (red when clear)but it should work clean. ie no dim lights. Once you got that straight I suggest you add another inverter transistor and use that to drive you signals. If that works then goodbye relays.

Ok, right about now a schematic would be good. I think I got it, gimme a while to sort this. I tried another circuit for detection but that didn't work at all!

 

[MrDEB]

yes a revisied, proposed schematic is needed
I read the description several times and still get lost.
Now I know why people are going with comparators.
I was doing a search and found an interesting circuyit using a 555 as a voltage controled switch.

 

[angie1199]

I was doing a search and found an interesting circuyit using a 555 as a voltage controled switch.

Ok, I got a few 555 timers and they are cheap compared to relays.

Right about now I'm willing to try just about anything. I'm so sorry I got you both involved in this, I didn't realise this was going to be like searching for the golden fleece!

One question, how do I test if a 393 comparator is working?

 

[angie1199]

Ok this is what I built. Red is active with yellow on previous signal active.

This is with or without loco present.

I actually used a 3.3K resistor as I don't have a 3.9K

 

[angie1199]

Just added a 1M pot between Twin T Collectors and T3. Green begins to light at around 380R

 

[MrDEB]

problem is we tried a transistor as the detect switch to ground and it didn't shut off enough?
why??
still contemplating the reed relay.

 

[MrDEB]

maybe in left field but it works
**broken link removed**
wrap with several turns of wire, pass some current and you now have a relay.
you may have to experiment on number of turns.
suggest buying couple and try out.
thinking connecting to twin t uinstead of usng relay.
on the 555-found here **broken link removed**
voltage controled switch
kinda works like a voltage comparator.

 

[Raiway Pete]

Ok this is what I built. Red is active with yellow on previous signal active.

This is with or without loco present.

I actually used a 3.3K resistor as I don't have a 3.9K

That's cool so far. Now put another transistor in the circuit. First take your detect signal and connect it to 12v with another 3.2K resistor. Then connect the junction of the new resistor and the collector and use it as the input to another transistor. The open collector of that should now be used to drive your signal controller. You should now have four tansistors in the circuit. You should have two for the Twin-t which is normally off with a high collector, one for the booster which is normallting and a collector close to ground and one for the signal driver which is normally off. When the Twin-T is triggered it will turn the booster off and that will turn the driver on.

I sent you guys a diagram oodles ago.

I have to find it.

 

[angie1199]

Ok Pete

Allowing that my schematic is correct so far, the wire labelled detect is from the signal circuit. It's already positive.

Do you mean to add a resistor from the 12V and join it to the positive detect feed from the signal circuit and the collector of a 4th transistor?

If so what connects to the base and emitter of the 4th transistor?

 

[Raiway Pete]

That's why the UK and USA are not manufacturing much anymore and we all import from the middle/far east. The Unions kept striking for more money, that put up prices for products, everyone else striked for more money to buy the more expensive products, and so on, Vicious circle till companies decided to get stuff made abroad for cheap prices and import, and now the UK has 2.5 million unemployed. And yet no one sees the logic that follows!



Ok, right about now a schematic would be good. I think I got it, gimme a while to sort this. I tried another circuit for detection but that didn't work at all!

Here is what I have on my workbench.

All transistors are 2N2222As. Your pot is only isolating the Twin-T transistors and turning T3 off. Hm! Add the third stage.You can leave out the RC debouncing network and put a 10 to 12k resistor between the collector of the booster and the base of T4.

Once it's is working add R6 and disconnect your DCC power from the track. The twin-T should still detect. Go fer it.

 

[Raiway Pete]

Ok Pete

Allowing that my schematic is correct so far, the wire labelled detect is from the signal circuit. It's already positive.

Do you mean to add a resistor from the 12V and join it to the positive detect feed from the signal circuit and the collector of a 4th transistor?

If so what connects to the base and emitter of the 4th transistor?

I just sent you a new diagram. Connect your detect (now open collector)output from T3 to 12v with a 3.9K resistor. You now have a plain ole' amplifier. Now connect the collector of T3 to the base of T4 with a 10 or 12K resistor. The emitter of T4 goes to ground and the collector of T4 is the new open collector 'detect' output. If you connect that to your signal controller it should indicate a green until the Twin-T triggers. Then the reds and yellows should come on.

 

[angie1199]

Ok, haven't got your schematic as yet but this is what I tried and the sim says it should work.

Tried it on the real thing and red with yellow on second block stay on.

 

[angie1199]

Ok, update on my last.

I hadn't connected the two gnd's together. Now the gnds are connected, the red and yelow are nearly out with the greens nearly at full with loco stationary.

When loco moves they dim more and the greens get brighter slightly.

 

[angie1199]

Tried your circuit and

No loco: greens all the way.

Loco: current block, green on, red dim
. ...... second block, green on, yellow dim.

Loco powered up: red and yellow dim further but still lit.

Admittedly I have had to use slightly different resistances and have no capacitor.

 

[MrDEB]

GOT your posted circuit working in TINA

wish I could post circuit but my PAINT program won't retrieve the clipboard data? (shift/print Scrn) paste into PAINT.
been working all along until TINA crashed yesterday?
Anyway, add a pot between collectors of T1 nd T2. 1M set at 80%
what I did was place a LED into the collector of the T4. adjusted pot until LED showed no current with 10-10k resistor across track rails.
connected to block sig circuit and volia it worked. no dim LEDs (I put amp meters on all the sig LEDs.
Maybe by reseting the computer it might get the clp board working again.

 

[Raiway Pete]

Ok, haven't got your schematic as yet but this is what I tried and the sim says it should work.

Tried it on the real thing and red with yellow on second block stay on.

Angie,

I don't know what went wrong. I sent you the diagram yesterday and even confirmed that it was attached to the mesage. Try again.

 

[Raiway Pete]

Tried your circuit and

No loco: greens all the way.

Loco: current block, green on, red dim
. ...... second block, green on, yellow dim.

Loco powered up: red and yellow dim further but still lit.

Admittedly I have had to use slightly different resistances and have no capacitor.

OK I guess the circuit diagram will explain it. But the third transistor's emitter should be connected to ground and not to the base of T4. Then take a 10 oe 12 K resistor and connect that to the base of T4 and to the collector of T3. Right now T3 is conducting and causing T4 to conduct. When the Twin-T triggers T3 cuts off leaving T4 with a very high (open ??) to 12v. This does not turn T4 on fully. Check the diag I sent you and confirm that you have it please. I missed something last noght.

Pete

 

[angie1199]

wish I could post circuit but my PAINT program won't retrieve the clipboard data? (shift/print Scrn) paste into PAINT.
been working all along until TINA crashed yesterday?
Anyway, add a pot between collectors of T1 nd T2. 1M set at 80%
what I did was place a LED into the collector of the T4. adjusted pot until LED showed no current with 10-10k resistor across track rails.
connected to block sig circuit and volia it worked. no dim LEDs (I put amp meters on all the sig LEDs.
Maybe by reseting the computer it might get the clp board working again.

Does it say there's no clipboard data?

Try just hitting Print Screen, not shifted. I've never had to use the shift key on mine.

 

[angie1199]

I don't know what went wrong. I sent you the diagram yesterday and even confirmed that it was attached to the mesage. Try again.

Yeah, sorry, my fault. I thought you meant you'd emailed it, not attached it and I didn't see it on the last page of the forum

Got it now. Tried it but I don't have all the components I need or the right values just now. I've used

R1 = 3.3K
R2 = 4.3K
R3 = 2.2K
R4 = 12K

And I only got a 47uF electrolytic cap

 

[MrDEB]

got it working!!!

no relays etc.
I simed Petes circuit yesterday = nada wouldn't work?
here is circuit I tried in TINA as per Angies suggestions and VOLIA it worked.
tried a 10 - 10k resistor across the rails. ALL a go
I see no posable dim LEDs as the amp meters show none.
the "detect switch" transistor shuts off completely etc.
now have Angi actually build circuit for actual testing.
I would breadboard but have several Christmas projects to finish plus I have no 18v AC supply or 18V dc supply.
ALL my voltage supplies are batteries.