There are several suppliers of hardware units to connect to a model railway but I shall restrict this list to those I have used personally.
The Model Electronic Railway Group is a non-profit making organisation based in London, England and has nearly 1000 members worldwide. They are a club (membership fees payable annually) and produce a quarterly newsletter and technical bulletins, run a discussion forum on yahoo, and also make kits of useful electronics modules available to members. It is these kits that we are interested in here. As kits, you need to assemble them yourself but mostly they are easy to assemble and get working.
Lamp twinkler. A simple circuit to randomly flash lights for perhaps a bonfire or a welding torch.
Point motor drive (PMD). Instead of running long wires from a CDU to solenoid motors this puts one CDU on each motor. The wire back to the control panel is now a low current signal wire.
Point motor relay (PMR). As PMD but with additional relay to allow frog switching.
Hector. An infra-red train detector. Not for use in direct sunlight.
Computer or control panel interface modules (RPC series). These 'stack' together and put all the inputs and outputs on a single cable back to the computer (or control panel).
SRI4. 32 input lines such as button or reed switch wired to ground.
SRO4. 32 output lines capable of driving half an amp each. Useful to drive lamps, LEDs, and PMD modules.
FTC. 8 track occupancy detectors for DC layouts.
DTC. 8 track occupancy detectors for DCC layouts.
DPR. 8 double pole changeover relays.
RPIC. Plugs into the top of a 'stack' of the other RPC modules and connects to the computer using COM port or USB.
PTP. Connects two stacks together so that inputs on one connect to outputs on the other. Useful for control panels.
For more information on these and many other kits refer to RPC and Merg
Tcc can drive all these modules. It is also quite easy to write your own software to drive them.
We are a non-profit making group and currently produce (in limited quantities) kits of just one device:
QTU. Four throttles which can be manual, autonomous or computer controlled. Also general purpose inputs & outputs, relays and analogue inputs. Compatible with Merg RPC range. Can be scripted to perform some automation autonomously and/or can be controlled from a computer (over a COM port) in the same manner as Merg RPC modules. More advanced and not recommended for absolute beginners.
QTU kits are available as full kits and as partial kits containing just the hard to get parts.
Only Tcc is currently capable of driving QTUs.
Also refer to sensors for information about the types of sensor that can be used to monitor the progress of your trains.
You can also make your own.
There is plenty of scope for making gadgets to control or monitor things on a railway. The easiest way to interface them to a computer is by using the Merg RPC SRI4 or SRO4 modules, or the ready made modules such as TrainBrain from CTI.
For example this is my first design of computer controlled throttle. No PCB has ever been made and hence it not available as a kit. I made 8 of them on stripboard. This was the forerunner of my QTU.
CTI is a commercial outfit in the USA which makes a range of ready assembled and tested modules:
TrainBrain. 4 inputs and 4 single pole C/O relays.
Signalman. 16 outputs to drive LEDs. Intended for signals.
Watchman. 8 inputs.
Dash-8. 8 single pole C/O relays
SmartCab. A computer controlled throttle that can drive a single DC train.
These modules all 'daisy chain' on a single COM port. The only things needed to connect one or more to the computer is an adaptor block and some cables.
For more information information on these and other modules refer to CTI
Both Tcc and CTI's own software TBrain can drive those modules.
Heathcote electronics is a commercial outfit in the UK which makes a range of ready assembled modules:
IRDOT. An infra-red train detector. I have used about 50 of these with modest success.
Refer to Product list for a full list.
These modules can be interfaced to a computer (running Tcc or TBrain) using either Merg RPC or CTI modules.