The following photos shows all the movements that took place from 07th Feb to 27 Feb. Unfortunately I didn't record the movements that occurred during the period of 01 Feb to 07 Feb. From the ones that were recorded, there was a total of 46 movements. This show how much I am enjoying the layout - obviously there are times when I am not motivated, doing other things on the layout, or too busy doing other things that are not model railway related.
As I have explained in my previous posts on how I operate my layout which is basically from the viewpoint of a locomotive driver calling on shift to do a job from one main town to another main town, both having a crew change stop.
Given the small layout I have, I use the same station area as multiple places that we pass through until arriving at the next main town where this driver gets out and clocks off.
This entails a few laps of the layout. I have settled on two inner laps and then one outer lap where the station is located.
I am always looking at ways to enjoy this small layout. One issue I have with this operation is the changing of points every-time I leave the outer loop/station area to traverse the two inner loops (which represents some distance between stations). Instead of enjoying the layout from different viewpoints, I am called back to the location of the layout where I can change the points, one is operated by a Modertec Lever and the other by a Tortoise Switch machine.
I know I could use a decoder to control both if I replaced the Modertec lever with a tortoise, but that would entail more cumbersome button presses on the throttle. Wouldn't it be good if I could automate this whole concept, namely, for every two passes of the inner loop, the points would change to the direction of the outer loop and every time a train was in the outer loop, the points would change and a path would be made to take the inner loop.
I researched whether this was possible and to my amazement I came across the following schematic that uses the LM324 OP-AM connected to an Arduino Micro-controller!
However I had some major thinking to do in the realm of how to code this. Lucky for me, I had some spare Current Transformers as detection circuits which I had built previously for my signalling project so I could use these as well.
Logic used to construct the code and the different scenarios I had to take into account:
Tortoise T1 Point near staging
Tortoise T2 Point near station
1: Travelling in the UP Direction
SW2 HIGH and SW 4 HIGH
T1
T2
ex staging
Goes Over detect A0
HIGH
HIGH
Goes Over detect A1
HIGH
LOW
Goes Over detect A1 again
LOW
LOW
Goes Over detect A0
HIGH
HIGH
2: Travelling in the DN Direction
SW1 HIGH and SW3 HIGH
T1
T2
ex staging
Goes Over detect A0
LOW
LOW
Goes Over detect A1
HIGH
LOW
Goes Over detect A1 again
HIGH
HIGH
Goes Over detect A0
LOW
LOW
3 - Travelling in the UP Direction
SW2 HIGH and SW3 HIGH
T1
T2
ex STATION
Initially Set: using flags in code
HIGH
HIGH
Goes Over detect A1
HIGH
LOW
Goes Over detect A1 again
LOW
LOW
Goes Over detect A0
HIGH
HIGH
SW4/2:Traveling in the DN Direction
Can be used as 2!
SW1 HIGH and SW3 HIGH
T1
T2
ex STATION
Goes Over detect A0
LOW
LOW
Goes Over detect A1
HIGH
LOW
Goes Over detect A1 again
HIGH
HIGH
Goes Over detect A0
LOW
LOW
MANUAL: When our train takes loop for Cross/Meets
SW1 HIGH and SW4 HIGH
T1
T2
When this SW5 SW4 set to HIGH
LOW
HIGH
After some thinking and coding, I got to the testing phase and then came the deployment phase. This took about one whole day to get all the toggle switches and wiring set up as well as the wiring from the Arduino UNO and the LM324.
Power was supplied and to my relief I heard one of the Point motors make that crawling sound. Good, now I need to run a train and see if the points set correctly, so I took a Down Goods and as it went over the sensor block of the outer loop, both points changed and made a path for the inner loop! Good!! Now, two passes of the inner loop and again, automatically, both points changed to make a path for the Outer Loop! WOW! Total automation of the points!!! I was ecstatic! Now I can walk round the layout whilst we make the journey from one major town, passing some intermediate towns and then arriving at out crew change location.
LM324 soldered to a veroboard (2 pins from the UNO which is not shown are connected to the LM324):
The only times I need to change points, is when leaving the yard and when re-entering at the end of the journey at the "other" location.
So I now have the signalling of the DOWN section near the station automated, points for the correct path automated, the two automatic signals displaying the yellow aspect and automated. The only section left is the UP side near the station to automate.
The following video demonstrates the LM384 automatically changing the points when the sensor is detected
The opportunity cost of spending all this time spent on the electronics side is that I have not spend any time on scenery. But the winds are full in my sails so I am not going to change course at this point.
The automatic signals as discussed in the previous post are now controlled by an arduino and display all three aspects. The red aspect is shown whenever a train passes the signal. It will then show yellow for a set period of time, then turn to green. This has been done for both the UP and DOWN signals
The main station and yard is governed by an UP Home Departure signals and an Arrival Home Signal with a LOW speed indicator as per the prototype. The LOW speed signal is used to bring in trains into the yard with a reduced speed as there could be obstructions/wagons on the same track.
I was able to use the one detection circuit for both the Approach Home Head and the LOW Speed Head - so that made the LOW Speed detector circuit surplus. Another bonus of using the Arduino.
I spent the last two days re-wiring everything on that section of the layout and also took the opportunity to label the wires!
Now, I have these sets of signals on "Automatic" mode using a toggle switch (DPDT), or I can override the signals to manual, in case there is a cross or meet at the loop. Obviously, the LOW Speed signal is not set for automatic operation as this aspect is shown to bring a train into the yard.
The good thing is I can use the same code for the other side of the layout - in the UP direction, as the signalling setup is the same, with a DOWN Approach HOME signal and a UP Departure Signal.
I will have to leave this side of the layout for another time.
Arduino UNO wired up
This mess is the testing circuit
Down Home Departure Signal now wired up to the UNO
UP Arrival Home - Top Head now having the ability to show the YELLOW Aspect! Low Speed currently in the OFF position
Low Speed indicator currently ON - TOP Head showing Yellow aspect - this was for testing, however in real life and when not testing, the TOP HEAD will show RED when the LOW Speed indicator is ON.
The next project I have spent time on is with the Automatic Searchlight signals I built from scratch. These signals are deployed on the main Western line which I am modelling and I really like how they look. They are of a US design I believe.
I was euphoric when I got the signals to automatically change from Red aspect to Green as the train
approached, however now I can get them to also display the Yellow aspect with some programming of an Arduino. They will now look even more realistic seeing them display a yellow then turn to green after a short time.
Not only can they act as true automatic signals, I have them programmed to also be over-ridden and to go into manual mode - so if the train has to cross in a loop, I can display a constant Yellow aspect which then acts as a distant signal giving the driver plenty of notice of the Low Speed or Danger indication for the next signal - to slow down to enter the loop - just like in real life!
Furthermore, in real life, after a train has exited the block, these searchlight signals change from showing a Red aspect to a Yellow aspect, and then stay on this aspect until overridden by the central
controller.
I can also model this feature which is something extra that again adds so much to the enoyment. I remember as a young boy riding my bike to a railway crossing where these signals were present and to see them turn to green, drop to Red when the train went past, then when the train cleared the block, they would go to Yellow aspect and stay there. There were a pair of them just like on the layout.
Arriving at the railway crossing and seeing which one is yellow at the signal would tell me in which direction the last train came through. So, if the last train was an UP movement, and cleared the block, the signal would turn to yellow
and stay there.
If the next movement is a DOWN one, I simply switch it over, and the Up signal turns Red from Yellow, and the Down Signal turns Green from Red.The Signal will turn to Red when the train goes past the signal, then to Yellow aspect, then to Green Aspect, but if I am going to the outer loop i.e. going past a town and main yard and if there is a meet or cross, I display a Yellow aspect.The programming got tricky as I had to cater for bi-directional movements.
By using an Arduino, I save on two Detection Circuits I had made earlier which were used to change the aspect from Red to Green, and also the Signal Circuits that were made using a 556 timer that now become redundant.
On startup of the Arduino, one of the Automatic signals will show a Yellow aspect, and the other will show a Red aspect (opposing signal) - which one shows a Yellow aspect and which one show a Red aspect is purely random (however I have skewed it to show the DOWN signal a Yellow aspect more often as this signal is near my seat and looks really good from the control desk)
Rough Sketch:
I can expand on this and since there are three more Analog pins available which can be used for detection, I can do the same for the Approach Home Signals, although the Home signals do have a small LOW Speed signal as well....a project for another time.
