Llanerch Mydyr Diorama Paused

Introduction

Llanerch Mydyr is a diorama built on a kitchen cupboard door that I was given. The diorama represent a workshop yard of a fictional country estate set in West Wales. The depression period of the late 1920s to early 1930s was chosen since during that time some enlightened estate owners converted some of their property into workshops to provide employment for the estate workers. In the case of Llanerch Mydyr it is assumed that an existing barn was converted to a forge while other outbuildings were converted to workshops.

The design and and construction of the electronics and mechanics needed to control various lighting and mechanical features of the diorama are described here.

The construction of the model itself is touched on only insofar as it relates to the electronics and mechanics.

The original plan was to turn each feature on and off using simple mechanical switches, but I decided it would be more fun to use an infra-red handset to control everything.

Construction of this diorama has been on hold since early October 2023. I decided I needed to develop my skills on less complex projects before completing this one, so embarked upon a couple of other, simpler, dioramas. These are Transfer Sidings in progress and 1960s Garage Scene completed. When work will restart on this diorama has not yet been decided.

Project Brief

There will be several buildings that are to be lit. Some buildings will also contain fireplaces etc where flames should be simulated. Some mechanical gimmicks are also planned that will be powered by low voltage electric motors. The diorama itself may also be lit by means of concealed LEDs to simulate day and night conditions.

The brief is therefore to control the lights and motorised items by electronic means, using one or more microcontrollers. Support should be added to enable operation via an infra-red remote control. In addition, a program to control a fixed sequence of events could also be provided.

Sub-projects

The project falls neatly into 6 sub-projects, some of which are detailed on separate pages:

Infra-red control

The diorama is to be controlled using an infra-red handset that communicates with an infra-red receiver on the front of the layout.

In progress

Model lighting

All lighting on the model is contained within buildings and uses LEDs.

In progress

Mechanical features

Mechanical features must be able to be switched on or off individually. In addition there should be a master “all off” (panic) command. Features being considered are:

  1. A dog with a wagging tail.
  2. A rabbit popping in and out of a burrow.
  3. A dog chasing a squirrel or rabbit.

Some features have on and off states while others don‘t have such a state. For example the dog is either wagging its tail or not and the rabbits are either in or out of their burrows. But the dog chasing a squirrel is a feature that must be started and left to run to completion: there is no point in turning it off part way.

Not started No further information.

Ambient lighting

Ambient lighting is to be used to emulate different times of day. The lights should be hidden out of view above the diorama. Lighting should be dimmable in discrete steps from full (bright daylight) to off (night).

Not started No further information.

Central control

This sub-project is the “brain” of the diorama's control system. It must respond to commands from the infra-red control sub-system to control the model lighting, mechanical features and ambient lighting. It may also manage automated events by means of pre-programmed sequences.

In progress

Power supply

Power is provided by a 9V DC supply, with 7.8V and 5V taps available to power other sub-systems. The power supply module requires an external 9V transformer delivering power via a 2.1mm × 5.5mm socket. Both centre +ve and centre -ve plugs are supported.

Completed

Experiments

The following experiments have been carried out:

#1: Infra-red remote controller

Tests the code and circuit needed to interpret the encoded infra-red signals sent by the remote control.

#2: Power supply

Test the circuit used to prove the power supply design.

#3: Optimum Microcontroller LED control

Determines the optimum way to drive the numerous LEDs used to light the diorama whilst using the minimum number of microcontroller pins.

#4: Inter-Microcontroller Serial Communication

Investigates the feasibility of using serial communication to send data from one microcontroller to another.

#5: Inter-Microcontroller I²C Communication

Investigates the feasibility of using I²C to send data from one microcontroller to another.

#6: RGB LED colour balance

Determines the values of resistors required to balance the red, green and blue elements of the RGB LED used to provide user feedback in the infra-red receiver unit.

#7: Basic servo test

Uses the Arduino Servo library to move a servo and to check performance against expectations.