I have recently been upgrading some of my home automation. I already use Energenie Pi-Mote to control some electrical power sockets, I’ve now replaced some of my light switches with Sengled home automation light bulbs.

Initially I’ve been using my Pi-power software running on a Raspberry Touch Screen and some timed actions to automatically turn lights on and off at certain times of the day.

I’ve now reconfigured some of my now unused Amazon Dash buttons so that they can control both the Sengled Light Bulbs and the Energenie remote control sockets.

In the photo shown the dash button is placed on the normal light switch. It may sound like a folly to replace a mechanical switch with a computer based one that does the same thing but it does make sense in this situation. The reason is that this is a porch light between the front door and an inner front door. The light is needed to be able to see the lock on the door at night, but the switch is on the inside of the door. Using home automation I can set the light to come on when I normally arrive home and then another dash button inside the porch allows me to switch it on at times when I come home at a different time. Having a dash on the physical light switch gives a way of turning the light on and off without using the normal switch, which would power off the bulb and disable the home automation capability.

Unfortunately Amazon appear to have discontinued the regular Dash buttons. They have created an IoT Amazon Dash Button it’s much more expensive than the product specific ones. If you have some old dash buttons around then it is a useful way to give them a new lease of life in home automation.

Using Amazon Dash python module

This uses the Amazon-dash project on pypi. Installation is straight forward using pip3.

On a Raspberry Pi using Raspbian use
sudo pip3 install amazon-dash
sudo python -m amazon_dash.install
(On other Linux distrubtions you may need to use pip instead of pip3).

You then need to edit the /etc/amazon-dash.yml configuration file with the MAC address for each button and the event that needs to be triggered.

The Amazon Dash buttons first need to be registered through the Amazon app (but don’t selected a product otherwise you’ll be ordering something each time you turn the light on and off). To find the MAC address for the buttons use the discovery option and then press the dash button:
sudo amazon-dash discovery
This value is then used for the triggers in the configuration file.

I used IFTTT (If This Then That) for my Sengled home automation light bulbs and the web interface I created for the Energenie Remote Control sockets.

To use IFTTT you first need to register through the website and create a webhook (Maker Event). To find the unique code for your services go to the Services in you account. Click on Webhooks and then settings and you will see a long code as part of the URL. That needs to be used as the ifttt code in the configuration file.

These are the entries used for the IFTTT connections:

  ## Porch light from hallway
  FC:A6:68:11:22:33:
    name: Mentos button
    ifttt: myIFTTTlongcodevalueaaaabbbbccccdddd
    event: porch_light_toggle
    data: {"value1": "Mentos button"}


  ## Porch light from porch
  68:54:F1:11:22:44:
    name: Heineken button
    ifttt: myIFTTTlongcodevalueaaaabbbbccccdddd
    event: porch_light_toggle
    data: {"value1": "Heineken button"}

These are both toggle events, so each switch can turn the light on and off.

For the Energenie connections then using the “standard” sockets there is no way of knowing the current state of the plug, as even if you kept track of how it has been triggered through the pi-power app, someone could have pressed the button on the front of the socket.
There are new versions that can report back their status, I haven’t got any of those at the moment, but I hope to add that feature in future.

To overcome this limitation I have used two buttons. One to turn the switch on and one to turn it off. The entries for the configuration file are shown below:

  ## Turn Energenie Socket on
  FC:A6:68:11:44:33:
    name: Finish Button
    url: 'http://localhost/switchon?socket=0'  # Url to execute
    method: get  # HTTP method. 

  ## Turn Energenie Socket off
  FC:A6:67:33:44:11:
    name: Right Guard Button
    url: 'http://localhost/switchoff?socket=0'  # Url to execute
    method: get  # HTTP method. 

This is with pi-power installed on the same Raspberry Pi as the Amazon Dash button program. If using a different computer then that address would need to be included in the url.

Summary

This works well if you already have some of the Amazon Dash Buttons available, it’s a great way of making good use of those that you may have available.

The new IoT buttons are very expensive. I expect that they will work in a similar way (although they are designed for using AWS).

I have created some DIY home automation in the past. This was based around using remote control of mains electrical sockets (Home automation – controlling Energenie power sockets using a Raspberry Pi) but I also used a home automation light on one of my home lights.

Since then the number of commercial home automation devices has really took off, so I’m now looking at some other home automation projects. Most are designed for use with Google Home or Amazon Alexa to provide voice activation I’m looking at how they can be integrated into my own DIY projects.

I recently bought a SENGLED home automation lighting starter kit. This is a low cost starter kit with two light bulbs (available in B22 UK fitting or E27 European fitting). The total cost including the Hub and light bulbs is comparible to the cost of just the hub with some other manufacturers. One thing about most of the SENGLED products is that they are very easy to install. They are suitable for those that want to automate their house lighting without needing to rewire any wall switches etc. It does limit their usefulness a little as it means they can only be used with standard light fittings, but I can see the attraction of not needing to rewire a light switch.

SENGLED Hub and App

The kits comes with a SENGLED hub. It should be simply a case of connecting this to the router using the supplied cable and then connecting the power. It didn’t work first time for me, which I believe may be due to my home router rather than the hub. I restarted the router and then it worked OK since.

To configure the devices you need to download a mobile app called “Sengled Home” App from the Apple App Store / Google Play Store. There doesn’t appear to be anyway of doing this withough a mobile phone (a web client would be useful). The app allows you to allocate the room that each device is in and then turn the lights on/off and adjust their brightness. To add the devices then you need to be connected to the same network as the hub, but then afterwards it is available over the Internet. You can also change the hub to use wireless after setup, but it must be physically plugged into the router for initial setup. You have to relogin to the App on a fairly regular basis.

The app is quite basic but does include the ability to change the brightness of the lights, which I don’t appear to be able to do with any other service. Once registered with Sengled you can then register with Google home, Alexa or IFTTT.

Using these services then you can turn the lights on and off, but not control the brightness.

I think it’s a shame that there is no direct login to the hub. This means that you must register an account with Sengled and optionally with the other services. If they discontinue any of these in future then you could be left with a device that cannot be used.

DIY home automation with IFTTT

The Sengled hub does not provide any direct access for you to control the lights from a DIY home automation solution. The one thing it does provide is access through IF This Then That (IFTTT). IFTTT is a third party service that allows you to create applets which when triggered cause something to happen. Some of these are predefined, I used one which turns the lights on when I get home. It’s important to note that these don’t run in real time. I found that this particular rule would often trigger after I’d got home and entered the house, which defeated the purpose of what I was trying to achieve.

The most useful feature for me is the Maker Event which provides a web address that you can use to trigger actions. These need to be setup individually (one to turn each light on and one to turn each light off). Once created then you can get the URL for each instruction and include that in your own code (eg. using urlopen in Python, or curl to request the page). Unfortunately there is no feedback if that actually works (such as if the light is completely powered off), but it does at least provide the ability to make requests to turn devices on and off.

ZigBee

The lights use the ZigBee protocol between the hub and the lights. This is a protocol that has been used by makers for many years, popular with makers and particularly using an Arduino. The problem with this is that there does not appear to be any documentation about the communication with the devices. It is perhaps something that I can investigate in future, but that will involve some element of reverse engineering.

Summary

The Sengled light bulb starter kit is an easy way to get into home automation. It is a low cost solution that can be connected into a standard light fitting (assuming you have standard light fittings in your home). It works with Alexa, Google Home and can be used with home automation using IFTTT, but with all these they are limited to turning the light on and off, with no feedback of how successful the request is.

I was again involved with the Raspberry Pi Birthday Celebrations in Birmingham.

This years event was held at the STEMHouse in Birmingham. A makerspace / startup space designed for entrepreneurs and small businesses looking to create a product.

There was a strong influence of 3D printing and games programming at the event, including my own talk and hands-on session.

3D printing from Minecraft

During the event I gave a quick talk / demo on a program that I have developed on 3D printing from Minecraft.
It’s designed to lower the threshold for those looking to create 3D printed creations.

This is work in progress, but allows you to create a platform to design on, and then export it for use in OpenSCAD. More updates will be coming soon with additional features.

• Minecraft Print to 3D printer via OpenSCAD – project page

Starting game programming using Pygame Zero

This was a 40 minute practical session on getting started with Pygame Zero. It starts with a very basic pygame zero program, adding a background, some sprites and collision detection.

The complete game is where the player controls a unicorn (or other animal) to collect food which appears at random places across the screen.

• Pygame Zero beginners guide to starting games programming on a Raspberry Pi

Other activities

Other activities included talks and practical sessions on 3D printing, a practial Minecraft Python programming session, an introduction to the MicroBit and other talks.

The event was mainly attended by families. It was great to see so many young people take an interest in learning computer programming. My own two children attended and were both inspired by the activities. My son with the programming and my daughter with some of the 3D making opportunities.

I also hope to give my presentation at the UK 3D printer meetup in Birmingham later this year.

In this final part of the design for a 3D printed model railway building I’ve added additional features such as the door, windows and roof as well as adding a smoke generator.

These were all designed in TinkerCAD. These are designed in TinkerCAD and then exported for 3D printing.

The smoke generator is fitted into the top of the chimney. It is possible to buy smoke generators specifically for buildings, but unfortunately I was not able to find one from any UK suppliers. I therefore used one designed for a OO model railway steam locomotive. This worked, but the amount of smoke is a bit much for a building chimney. You can see the smoke effect in the short video below.

All the files are now available to download:

• Project page for G-Scale model railway building (includes 3D print designs)

Older posts

• Model Railway project page
   
• About the garden railway weighbridge building
• 3D printed garden railway building – part 1 – making a brick wall
• 3D printed garden railway building – part 2 – using code to lay the bricks
• Adding LED lights to the garden railway building

Changes to building version 2

Here are a list of the changes that I made since the original and the reasons for the changes:

Building as a single piece

Initially I’d separated the main part of the building into two pieces. There was two reasons for this, one was because it made it easier to open up the building to access inside; the other is because of the overhang at the top of the building which means that a lot of additional support is needed during the 3D printing process (the way that the additive 3D printing works means that you cannot create significant overhand without adding temporary support).

The main problem this created is that the two parts didn’t fit together quite as well as I hoped. The parts went together, but left a gap between the two parts of the building, especially at the corners. This was partly due to warping of the material at the corners (the corners curling up on the lower layers). I did have the heated bed set to a fairly high temperature (which appears to work better with some PLA and when printing smaller models). The reason I had the bed temperature quite high is that some other PLA I used needed a higher temperature to stick to the print bed, through trial and error I’ve now established that the FiloAlfa PLA actually sticks to the bed quite well at much lower temperatures which reduces the warping. So it maybe that is not be such a big problem with future prints, but joints like that are often visible in some way.

With printing the main part of the building as a single object then the print did use a lot of additional scaffold (temporary support) which needed to be removed afterwards, but other than using additional printer filament, which is then discarded, that is not a major issue.

Printing as a single object did work better for this, but this is a small building and is almost at the limits for my 3D printer. In future designs it’s likely that I will need to create the building from multiple parts.

Fireplace and chimney – adding smoke generator

On my earlier version the fireplace had been a separate part. This is partly because it was added as an afterthough. In the updated version I have included the fireplace and chimney into the main part of the building.
I also added a smoke generator, to do this I included a hole in the top of the chimney where the smoke generator could be installed and then a longer hole all the way through the rest of the chimney so that I could run the wires through that. The hole within the 3d printer is not very accurate (at least on my printer), so I had to go through it with a long drill, but it did at least provide the guide for the drill rather than risk breaking the model.

The smoke generator that I was able to buy is really designed for a HO/OO model train which fitted into the hole. As the generator is designed for a train it gives out steam in a puffing fashion rather than a continuous stream of smoke as you may expect in a fire in a building. It is possible to buy steam generators that are designed for buildings which would be more realistic, but I am unable to find a supplier that sells them from stock. I hope to order a more realistic smoke generator in future, but for now it does provide a smoke effect.

Roof with beams

The roof from part 1 is printed as a single piece. The roof is quite thin but needs a lot of scaffold to be removed and once that is removed it is a bit flimsy. In the new version I updated to add wooden roof trusses which provide additional strength and realism. I also made the roof wider with an increased pitch on the inside rather than the outside. This reduced the amount of scaffold (as scaffold is only required when there is around 40% to 60% overhang).

Adding the window frame

I have also added a window frame. This is printed separately using white PLA and fits in from the inside. I have then cut out some 2mm deep perspex sheet (transparent acrylic plastic) to fix to the inside.

Download 3D files

• Thingiverse download for Model Railway Building

This is an update on my first outdoor model railway building created using a 3D printer.

In the first version of the model railway building I created the building in several different parts, in this version I have decided on just 3. The main part is the body of the building, then the roof and finally the windows. As well as making the building look better this has made is possible to add additional features to the building which will be explained in the final part.

In an earlier video I have made a tutorial on creating a brick wall in TinkerCAD. This worked well, but is very tedious to add each brick manually. I have therefore created this new video which shows how you can partially automate this using code.

The code is written using TinkerCAD Codeblocks, which uses a graphical interface to add blocks of code. This is similar to how you would create code in Scratch or an other block based programming language. There is a limitation of 200 objects in Codeblocks, so I had to duplicate the completed object to add more layers.

The code created is available through the link below:

• Tinkercad Codeblocks – Building a wall out of bricks

If you have experience of programming then the code should be fairly easy to follow. You can also see how it works by slowing the speed of the code down within TinkerCAD.

The next stage is to add the roof and other details, which will be explained in a future video. Please subscribe to the penguintutor YoutTube channel to see future updates.

Update

The latest version is now available. Information on how this was created is available at:

• Project page for G-Scale model railway building (includes 3D print designs)

Details of the changes to the latest version are available version 2 of GScale model railway building.

Megaquarium is a computer game where you get a design your own aquarium tourist attraction. It’s like Roller Coaster Tycoon, based around a Sea Life Centre.

My son wants it as a Christmas present, which is great except in the days of digital downloads a bunch of binary digits doesn’t quite feel the same as giving something they can physically hold. That’s where my 3D printer comes in.

I’ve designed a physical 3D version of the virtual game. It includes 3D physical models that can be picked up and moved around and just as in the real (digital) game you can swap which fish are in which tank. The main thing is it provides something physical to actually give as a present, but it’s also functional and I’m sure there are many possibilities for turning into a game by creating some cards or something similar.

You can see more details in the video below.

The model is designed in TinkerCAD with credits for the fish, people and the cute octopus linked in the Thingiverse page. I did try and include a seahorse in one version, but it didn’t print very well as such small size and unfortunately the license doesn’t allow sharing the modified model under the creative commons license that I used.

The model is printed in PLA, except for the tanks which are printed in transparent PETG. I struggled a bit with the PETG on my printer (stringy and some discoloration of some of the filament) and so transparent PLA may have been better.

Download the Aquarium files

• Download the aquarium (3D megaquarium) files from Thingiverse

This year I’ve been creating a 3D model of a building for an outdoor model railway. Technically it’s a building for a weigh bridge rather than a house, but I’ve given it a Santa’s Grotto make-over for Christmas and so Christmas House sounds better.

The building is designed in TinkerCAD based on a real building on the Gloucestershire and Warwickshire Railway.

I’ve added a 3D printed snowman also designed in TinkerCAD.

Initially I added a smoke generator for the chimney, a white LED for a lamp and a red LED for the glow from the fireplace. To give it it’s Christmas theme I’ve also added a NeoPixel light inside the snowman and string of LEDs as Christmas lights. I have disabled the smoke as that was more appropriate when it’s outdoor with the railway rather than the indoor Christmas display.

Circuit to control LEDs, Neopixels and Smoke Generator

The circuit diagram is shown below (click on the image for a large version).

The circuit is designed for a Pi Zero with a custom HAT, which would fit better inside the building, but for the initial version this has been connected to a Raspberry Pi 2 with a half-size breadboard, which just fits inside the 3D printed building.

Although built on a bread-board wires need to be soldered to the LEDs.

Setting up the Raspberry Pi

To control the NeoPixel (RGB colour changing LED) then a library will need to be installed first. This is explained in the following worksheet:

Worksheet for configuring NeoPixels on a Raspberry Pi

Code to control the LEDs and NeoPixel

The following code should be added to a file called /home/pi/christmas-house/display.py

#!/usr/bin/python3
from gpiozero import LED 
from neopixel import *
import time

# config details for neopixel
LEDCOUNT = 1
GPIOPIN = 18
FREQ = 800000
DMA = 5
INVERT = True
BRIGHTNESS = 255

FIRE_PIN = 24
LAMP_PIN = 25
GREEN_PIN = 17
RED_PIN = 27

fire_led = LED(FIRE_PIN)
lamp_led = LED(LAMP_PIN)
green_led = LED(GREEN_PIN)
red_led = LED(RED_PIN)

timer = 0

# red / green chaser mode - toggle between red and green
# if 1 = red led on, if 0 then green led on
red_green = 1

rgb_colours = [Color(248,12,18), Color (255,51,17), Color(255,102,68), \
               Color(254,174,45), Color(208,195,16), Color(105,208,37), \
               Color(18,189,185), Color(68,68,221), Color(59,12,189)]
seq_number = 0

# Create neopixel object
strip = Adafruit_NeoPixel(LEDCOUNT, GPIOPIN, FREQ, DMA, INVERT, BRIGHTNESS)
strip.begin()
strip.setPixelColor(0, rgb_colours[0])
strip.show()

def led_change():
    global timer, red_green, seq_number
    timer += 1
    # if number is divisble by 6 then flicker red led
    if (timer % 6 == 0):
        fire_led.off()
    else:
        fire_led.on()
    
    # toggle red green leds
    if (timer % 10 == 0):
        red_green = 1 - red_green
        if (red_green == 1):
            red_led.on()
            green_led.off()
        else:
            red_led.off()
            green_led.on()

    # Color change snowman
    if (timer % 12 == 0):
        seq_number += 1
        if (seq_number >= len(rgb_colours)):
            seq_number = 0
        strip.setPixelColor(0, rgb_colours[seq_number])
        strip.show()

lamp_led.on()

while True:
    led_change()
    time.sleep(0.25)

It can then be run using:
sudo python3 /home/pi/christmas-house/display.py

The code works by having a single loop which runs and then pauses for 1/4 of a second. During the led_change function the timer is incremented and if the value of the timer reaches the appropriate factor then it changes which LEDs are on etc.

The % provides the modulo value, which is the remainder after dividing the number of the left by the number on the right.

For example
timer % 12
Will be exactly zero whenever the value of the timer is a multiple of 12. As the timer value incrementes every quarter of a second this means it updates every 3 seconds.

Startup automatically

To have the code run automatically when the computer boots then create the following file (you will need to sudo to root to have appropriate permissions) as /etc/systemd/system/house.service

[Unit]
Description=House

[Service]
ExecStart=/usr/bin/python3 /home/pi/christmas-house/display.py
User=root

[Install]
WantedBy=multi-user.target

Give it permission to run:

sudo chmod +x /etc/systemd/system/house.service

Then set it to start automatically using:

sudo systemctl enable house.service

YouTube video introuction

I’ve also created a YouTube video introducing the project. Please subscribe to penguintutor on YouTube.

Making the 3D Models

Details of how I made the 3D models in TinkerCAD are available below:

• Design for a 3D printed model railway building in TinkerCAD
• Design your own 3D printed snowman using TinkcerCAD

This is a model that I’ve made using TinkerCAD. A snowman designed for 3D printing on a home 3D printer. It’s been created to approximate G-Scale (1:22.5) for outdoor model railways. It’s also hollow so that you can insert an LED inside and have it light-up (assuming it’s printed with a light coloured PLA) so it can be used as a light-up Christmas decoration.

The photo below show the 3D snowman printed on a Wanahao i3 Duplicator Plus using white PLA.

To make it easier to hollow out there is a central cylinder which can be removed. The snowman arms are very delicate at this scale. If the size isn’t important then you may prefer to scale the model up a little which can be done within your Slicer software (eg. Ultimaker Cura).

Download 3D model files (STL)

• Download – Snowman on Thingiverse

Video – Beginners Guide to TinkerCAD

Below is a video on how to recreate the snowman in TinkerCAD

More models

See the PenguinTutor 3D projects page for more 3D models, including more model railway models.

There are many different misconceptions about creating model railways and the people that are involved. I’d therefore like to start by dispelling some of these myths and explaining what I think that model railways is about.

The 3 Golden Rules of Model Railways

Many people have come up with different rules for model railways, here’s my take.
If you are wanting to design your own personal model railway then there are only three rules that you need to follow.

1. Safety is always the top priority
2. It’s your railway so you can do what you want
3. See rule number 2

Okay, so that’s only really 2 rules, but both are just as important. You also need a reason to be spending all that money, so I included fun as a third rule in the description below.
This is for your own railway on private land, but if you are on a public display then new rules apply – see Public Display Railways rules.

Rule 1 – Safety

I think it’s fairly obvious why rule number 1 exists, but remember this applies to both the modeling and the display of the model railway.

Who is going to view the railway and in what environment?
Have you checked there are no exposed live electrical components that could be a danger. For example check the plug is wired correctly and that there is no damage to the mains electrical cable. If it’s an outdoor model railway then are all mains electrical parts suitably waterproof or located indoors?
If young children are going to be present then make sure they are no at risk of choking on small objects. In many cases this is best achieved through close supervision whilst they are viewing / interacting with the railway, but you may also want to consider adding a transparent plastic (perspex) screen to prevent them reaching the railway or designing a layout that is child friendly.

When modeling – do you know how to use the tools, are you following the manufacturer instructions and are you wearing appropriate PPE?
When dealing with small models then it’s easy to make the mistake of thinking that the risks are also much smaller, but that is not the case. When using something like a rotary multi-tool / drill then the tools can be be spinning at thousands of revolutions per minute. If a small piece of metal or plastic is thrown out at that speed and hits your eye then it can result in permanent loss of sight. In fact due to the thickness of the cutting blades there is an increased risk of a blade breaking off and hitting you. I know that from experience (fortunately I was wearing eye protection at the time, but it could have been different).

Rule 2 – It’s your railway

If it’s your railway then you can do what you want, which is to say that you make up your own rules of how you want the model railway to look. This is based on you wanting to create a railway for yourself. If you are wanting to participate in a club model or create a model for public exhibition then there may be other rules you need to apply, but when modeling for your own pleasure then you make up your own rules.

Rule 3 – It should be fun

Why are you creating a model railway. For most of us it’s because it’s something you enjoy (or you want to try it and see if you enjoy it). Which comes back to rule number 2, you decide what the rules are that will make it enjoyable for you. If you can’t afford to buy expensive scale models and want to include some cheap toys in your layout (Playmobil works very well with Garden Gauge Railways), or if you really want to incorporate something but it’s not quite the same scale or a different era then do it. Feel free to do what you want and as long is it makes you happy then it’s the right thing for you.

What kind of person likes model railways?

You may be under the impression that model railways are just for boys and men that still think they are kids, but that is not the case at all.

Model railways are good for all ages, from young children to great-grandparents,and ability. It’s also just as much fun for girls, whether the girl is into science and engineering and likes those aspects of building a model railway, whether they are a historian and want to make it historically accurate or they prefer to make some kind of fantasy / science fiction world. There is not reason that model railway should be any less appealing to girls as it is to boys. There is something for everyone.

Sci-fi layout winner of the British Model Railway Challenge TV program.

The skills involved in creating a model railway depend upon the type of layout. They could vary from digging the garden and building a brick wall to support an outdoor railway, to painting N Scale model people that are only 1cm tall. There is lots of scope for STEM subjects such as electronics and mechanical engineering; all manner of art from creating scenery items or painting realistic backdrops; and a role for the historian to check on historical accuracy (if that’s the type of layout you want).

Most model railway layouts attempt to create an element of realism, but if that’s not your thing you could create a fantasy land with unicorns, sci-fi space planet or a scene from a horror movie, whatever direction your imagination takes you.

How much space do you need?

You may be thinking that you don’t have the space for a model railway, but having seen some space constrained layouts I’m pretty sure that’s not the case. Many OO scale layouts can fit comfortably under a single bed, N gauge is smaller still and I’ve seen an impressive 9mm narrow gauge layout which packed away inside a box smaller than a briefcase. T-scale is smaller still, although the tiny size of those models is a little too small for me (although amazing to see some of the models that some people have made). Just take a look at the photo below of one that I saw at the Warley Model Railway show 2018.

If you haven’t got space in the house, then how about the garden (if you have one)? It’s a great way to involve the whole family by choosing plants to grow next to the railway.

Guidelines / Information / Hints and Tips

As I said the only really rules for your own railway are the ones you impose on yourself. I have put together a few guidelines that you may want to consider. Feel free to go against these guidelines if you have a reason for doing so.

Scale, ratio and gauge

These are three terms that are often used interchangeably, although there are some subtle differences. Scale refers to something having a direct correlation with real size (usually smaller). The difference in size of a scale model is normally expressed as a ratio, often following one of the common named ratios. The gauge is the distance between the track, but often scale and gauge are used interchangeably as the distance between the gauge is normally based on the same ratio as the scale for the models (though not always quite the same).

The standard gauge for British (and most other country) full size track is 4ft 8½in. Model railways are often based on a scaled down version of standard gauge. Some railways are closer together than standard gauge which is often known as narrow gauge or light-railways. These narrow gauge railways are popular for some railway modellers as they make good model layouts with only a few carriages. The ones marked in the table with an * are narrow gauge railways.

The table below shows some of the most common scales used for British and European model railways.

* These are the gauges used for narrow gauge tracks.

Some model railway enthusiasts are very strict in ensuring that where possible their model is true to their desired scale. It is however fairly common for some to use a similar scale when off-the-shelf models are not quite to the same scale. The use of HO and OO on some models where some scenic items intended for European countries are mixed with UK OO scale and a similar thing can happen with 16mm and G-Scale (although the track gauge is different the model scale is quite close).

Belos is an example of a narrow gauge – G-Scale railway.

Era or Theme and Historical Accuracy

Deciding upon a theme or year for the model railway to be based should be an early consideration. You should also decide on how important historical accuracy is to you.

This is perhaps one of the most controversial areas: the model railway purists may insist that you shouldn’t include anything that doesn’t comply with the historical accuracy at the time however having made an investment in a particular item then you may be keen to include that regardless of it’s historical accuracy.

There are sometimes stories that you can use to incorporate the items from a different era. For example if you have a modern railway layout, but would like to include a steam locomotive then you could design in a preservation railway within the layout, or just give a story that it is a historical railway running on the mainline.

At the end of the day remember the three rules above. If you want to include it, but it doesn’t fit with the accuracy then it’s your railway and if you are enjoying creating it then it doesn’t matter if it isn’t historically accurate.

Weathering or New

When buying a model then the chances are that it looks like a pristine brand new version. Weathering is the process of making a model look more realistic by making it look older and dirty. Not everything needs to be weathered as it’s always possible that, if age appropriate, it really is a new locomotive just delivered from the factory. It’s unlikely that all engines and buildings would look brand new.

On the other-hand some people may not want to spray dirty black / brown paint over their brand new model. If that’s you then don’t worry, just leave it as it is and accept how it looks.

Public Displays

When it comes to public displays then there are additional rules that you should follow. These apply whether the display is part of an exhibition, an outdoor public layout such as one at a preservation railway station or an open display on your own land. The main thing is an additional responsibility for health and safety and public liability insurance.

In addition the health and safety considerations already mentioned you may need to look at hazards around the site and periodic testing and certification of live steam engines. For electrical layouts you may need to consider PAT testing of electrical equipment that is in reach of visitors (or better still keep mains electricity away from the visitors).

Liability insurance is a requirement for public displays. If you are part of a model railway society check with them as they sometimes provide public liability if you have an “open day” at your own railway at your home. If not then make sure you take out insurance for a public event.

Thought should also be made about how accessible it is to disabled visitors as there may be a need to make reasonable adjustments for disabled access under the E qualities Act, particularly for a static display.

One final thing that I feel strongly about is swearing. If you are on a public display there should be no need to use bad language particularly when young children may be listening. This happened to me recently as we visited an outdoor model railway at a preservation railway station. One of the members there was talking with other members and used a completely inappropriate 4-letter word which was clearly audible to my son. Once may be a slip-up but then he repeated the same word again straight afterwards. It’s a word that I certainly wouldn’t ever use whilst with my children and was completely inappropriate.

Summary

There are very few rules beyond the need to keep yourself and others safe.

In my opinion having fun is much more important than realism or historical accuracy, but that is something you may want to think about when creating a layout for public display.

This is my first attempt at creating a proper scale model for 3D printing. In this case I am creating a weigh building in G-Scale. This has been a huge learning curve. I’ve since learned from some of the issues in the first model and so part 2 will improve on the techniques shown.

The model is based on a real building located at Winchcombe Station on the Gloucestershire and Warwickshire Steam Railway. The building is opposite the entrance to the station. See the photo below:

The 3D printed version is approximately in G-Scale (1:22.5 scale). This is also known as garden gauge railway, designed for narrow gauge trains running on 45mm track. It may also work well with 16mm model railways as the size is perhaps a little smaller than G-scale. The main difference between the real building and the scale model is that the model does not use the different coloured brick that is in a curved shape above the window and where the side walls meet the roof. The main reason for this is the time it would take for a feature that I expect few would actually notice if I hadn’t pointed it out.

Designing the model

The model was designed in TinkerCAD. In this version I have created the model in several parts.

• The main part of the building from the floor to the top of the door
• Upper part of the building (including the side walls up to the pitched roof)
• Internal fireplace and chimney breast
• Roof
• Windows (not shown in the photo above)

In general this works, but in a later version I will combine the first three into a single model. The reason for this is that there was some warping of the upper part of the building (perhaps due to the bed temperature). Although this is something that I will need to revisit again in future when creating larger buildings.

The internal fireplace is something that I added as an afterthought on this model, but will be included directly in the next version.

I have created a short video on getting started with TinkerCAD which explains about how to create a simple brick wall.

• Creating a G-Scale model railway brick wall in TinkerCAD for 3D printing

3D Printer

The printer that I have is a Wanhao i3 Plus Duplicator. This is the perfect size for creating this 3D model, which fits fairly comfortably on the build plate. It would not be possible to create a larger building in a single print using this printer. If a larger building is required (as I hope to do in future) then the model will need to be separated in parts and then fastened together.

Brick effect PLA filament for 3D printer

One of the challenges was in finding an appropriate colour PLA to give a good brick effect. The problem with most suppliers is that the closest the provide is either red which tends to be a bright post box red colour, or brown which is too dark. I had tried experimenting with different colours with acrylic paint when creating a brick wall previously, but then I came across a brick effect PLA filament from Filo Alfa. I couldn’t find a UK supplier for the FiloAlfa PLA so I ordered it direct from the manufacturer in Italy. Unfortunately whilst the cost of the PLA is quite reasonable, the additional cost of shipping meant it was in fact very expensive. I am however very happy with the quality of the PLA which works very well in my Wanhao 3D printer.

Brick Effect PLA 3D printer element from FiloAlpha

The rest of the building (roof and window frames) is made using my normal 3D printer filament for which I normally use either Prima Value PLA (1kg reels) or Prima Select PLA (750g reels) depending upon the colour availability.

Update

The latest version is now available. Information on how this was created is available at:

• Project page for G-Scale model railway building (includes 3D print designs)

Details of the changes to the latest version are available version 2 of GScale model railway building.