555 and 556 Timers for Colour Light Signalling

It's been quite frustrating as I continue to build my signal circuits and have been all consumed in this task.  I had to build additional detection and signal circuits using the 555 and 556 timers.  I also delved deeper into the understanding of these ICs.  It wasn't easy until I leart about the Comparators inside these devices. This video helped alot.
After building one of them, and connecting it to the signal circuit, the LED would not stay on Green.  It would drop back to Red even without the detection circuit connected.  I even managed to blow two of the 555 timers and I couldn't work out whether I had the problem in the signal board or the detection board.
The smoke that came out at one time was quite impressive!
Eventually just by chance I found out the problem.  I had connected one of the polarity Caps the wrong way round. 
Still, replacing the cap didn't help.  I was about to then build a new circuit when I decided to remove the cap, diode and transistor and replace them with new ones.  I began to have some success.
Also the sensor wire connected to the board was another issue and was "flaky" holding on to the Green aspect. 

Another issue I had was the Yellow aspect would show instead of Red.  This meant that both red and green were ON at the same time (Pins 5 and 9 of the 556 Timer).  I couldn't work out what was going on.  After spending alot of time trying to find out the issue, I gave up in frustation and eventually built another Signal Circuit and put that one away for now.  So now I have a detection and signal circuit that needs to be looked at - should be a good trouble shooting task not!

I am now done with the 6 signals which covers entry and exit to and from the yard.  Eight signal and detection circuits were used as both the approach Home signals have a Low Speed Indicator to enter the Yard tracks or Road 2.
I think it's really cool to see the signals turn to the Red aspect as the loco passes the post, just like in real life.  I think the extra trouble is well worth it especially with this amazing little timers.

Now I need to think about how I am going to automate the Automatic signals which will be placed in the inner loop representing the connecting and country run between stations.  Not sure whether I should go down the Arduino path or stick with the Discrete components.

The Detection Circuits

Can you spot the incorrect capacitor?  It's difficult to do.

Test mock up

Blown 555 Timer

Signalling Bug

Unfortunately the Signalling Bug hit me over the last few days.  By this I mean I began to install Colour Light Signals on the layout.  Once I started I could not stop.  Unfortnately this has given way to doing scenery and also not running any trains

A few years back I build some searchlight signals and also some circuits to automatically change the Signals from Proceed to Danger once the train has passed the signal.  I really like seeing this just as it is in the prototype.

I also thought hard how to avoid the rats nest of wiring I ended up with last time in my eager to get it up and running.  So now what I do is secure the circuits to some ply and use this as some sort of work area. 

I ended up having to buy some 3mm bi-colour LEDs as some blew and only would show RED or GREEN.  What a pain it is to get them soldered back on.  Today was especially a frustrating day after seeing the Arrival UP Home signal not displaying the GREEN aspect.  So I soldered on a new LED and still no GREEN aspect.  Tracing back the enamel wire I had connect the wire for the GREEN leg to COMMON so I had to go through the whole exercise.  Very frustrating and sometimes I think is it really worth it.  But seeing the Signals light up really makes up for the frustration. 

Each Signal head that needs a detection circuit as well requires alot of wiring!  For the three signal I have, that is four such circuits, which includes the LOW Speed arrival signal which was used on SearchLight Signals back in the day.  Now I want to control all these signals from one are.  So each signal needs three wires to this panel which makes it 3 x 4 = 12 wires.  This is just for the DOWN end.  I also need to do the UP end.  Anyway here are some photos.

Schematic

Here's a video showing how the signals operate:

Ignore the Left Green Aspect at the beginning of the video as I was in testing phase:

https://youtu.be/9d6eaI0ONX4

Progress and Sound Decoders

Over the Christmas break, I started ballasting the layout.  Quiet happy with it now.  I did add an extra Road, Road number 5 - makes shunting the main industries much easier and also most VR yards had five roads.
I am now using the Yard as “Staging” - trains arrive and depart from here - run a few loops in the inner loop which represents the country and then comes back in.
I also airbrushed the side of the rails a rusty colour.  Took about 1.5 hours.  Still have a small section to do.
Also borrowed Craig’s 48 Class which has the Full Throttle (FT) Sound Decoder from Loksound - quite impressive motor control and performance although the horn is little weak.
I have a Tsunami 2 Sound decoder in my B Class - the thing I like about the Tsunami 2 is the auto-notching feature.  The Full Throttle sound decoder does not have this feature. 
It feels like if you want to be track-side, the Tsunami 2 is the one, if you want to be in the cab, the LokSound FT is the one.

B60 - Tsunami2 Auto notching:

Nice Lights on the LokSound:

Horn - sound little weak:

More sounds:

Now I am tempted to get sound for my Y Class!

Busy doing some more scenery work

I have been busy doing some more scenery work.  You can see in the following pictures some of the work done.  I tried to make a scene interesting and this was the main thinking in my mind as I set out.  The hardest challenge was trying to make the scenes flow together.
I ended up with the concept of a dry river running parallel to the railway.  I think this came out very well and it some how makes the layout look longer.  I wanted a river somewhere on the layout and always thought of running it through the tracks but on further thought, the river running parallel seems to be better.

I basically used soil which I found nearby and really like the different colours and hues.

Some footage

It's been a while since I posted any footage of the layout on this blog.  For those who are interested in seeing some movements, here are some videos:

Scenery Work

I have been playing God lately - in the form of Terra forming and scenery work.  For ground cover I used some soil which I scooped up on my way home from work one day and sifted this through one of those small tea-strainers. 

I also found a pretty good static grass applicator.  You can buy this in a kit and it goes together without any soldering required.  One uses a 12 V DC transformer and the output is in the range of 40KV. 

Being my first attempt, I am pretty pleased on how it turned out and enjoy watching trains pass in this open scene.

The photos show the progress so far.

The following photos with the morning sunlight:

Building a VR Signal Box from Plans

Here is my first attempt at making a building from styrene.  The plans are from Australian Model Railway Magazine and the building is of a two story Victorian Railways Signal Box.
The windows are from Ratio.  It is still far from complete obviously. I need to get some corrugated iron sheets, and the steps to complete the model.
I am quite pleased on how it has turned out.  It has been a joy to build and to see it come together.  The author of the article has done a very good job of explaining the steps to put together and build this signal box.