Stupid question

[alexstan]

I know this might sound dumb, but is it possible to manually override the Walthers traffic signal controller outputs? I e switch it off an manually operate the LEDS? I have a manually operated grade crossing near it, and I want the traffic lights for the intersection go red when the grade crossing lights are on. SO I don't have cars cleared to go thru the intersection but hit a red grade crossing. IE- I suppose it's not possible...

[JSperan]

I'm not familiar with how the Walthers traffic lights are wired and controlled but it seems on the surface like this should be simple enough.

Are there separate wires for each color light in the traffic signals?

[rrinker]

 Without knowledge of the internals of the circuit, the 'simple' thing to do would be to have a relay controlled by the grade crossing circuit in between the traffic signals and controller. WHen triggered, it would disconnect the traffic controller from the signals, and connect just the red light in the signals. This basically isolated completely the two circuits and should eb safe no matter what.

 With some knowledge of the circuit internals, or in some other way a know circuit (like the traffic light controller on Rob Paisley's site), it would be posisble to design somethign solid state to handle this.

                         --Randy

 

[alexstan]

Yes there are separate wires for each traffic light colour.

[DigitalGriffin]

A/B relays will do the trick.

With LED's you can use solid state instead of mechanical.

 

[alexstan]

Sorry I don't understand anything that is being posted...I'm only good at wiring DCC...not other electronics..

[DigitalGriffin]

What you need is something similar to this:

http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2095390_-1

When the train approaches the crossing and the crossing lights flash, you supply +4.5 Volts to the pin on this device.  This will cause it to switch from the A pins to the B pins (similar to a DPDT switch).  These B pins will supply the power to the red light on the walthers traffic signal, and on the 2nd and 3rd relay be connected to nothing (so the green and yellow will not light up)

You could also use a SPDT (Single pole double throw) like this panasonic model IF the traffic lights share a common ground.  (4 wires coming out of traffic light instead of 6)

http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=15034&

 

 

[alexstan]

for some reason if any power is supplied to the red lights while they are still attached to the traffic light controller, the other lights glow...

[DigitalGriffin]

That's why you need 3 relays.

Relay 1 (red light) A = walthers circuit B = your power supply

Relay 2 (yellow light) A = walthers circuit B = nothing

Relay 3 (green light) A = walthers circuit B = Nothing

 No train = Relay A

Red light = walthers circuit

Yellow light = walthers circuit

Green light= walthers circuit

Train comes by, triggers relay B

Red light = red light power

yellow light = no connection (therefore no light)

green light = no connection (therefore no light)

[alexstan]

But I need green on one route(parallel to the tracks) and red for the crosswise one.

[DigitalGriffin]

How many wires are going from the control box to the traffic lights?  I'm guessing it's 7. 

3 of those wires are dedicated to the perpendicular cross light.

Use the relay on those.  Although techinically speaking, I believe they should ALL be red.

 

 

 

[alexstan]

8.

[DigitalGriffin]

I just looked at the graphic.

It's 8, but the common (ground) can be used as 1 wire.  So techinically it's 7.  They provided the extra terminal for the perpendicular light which has it's own ground wire.  But there's no reason why you can't tie both to the same common.  If you don't believe me, just try it.

http://www.walthers.com/exec/productinfo/933-2306

http://www.walthers.com/exec/productinfo/933-2305