The PCB at right is the finished prototype of the P675S, as soldered
together by my
six-year-old daughter.
If it is this simple to
build and simpler to operate, you might be forgiven for expecting
weak features, but you will be surprised.
It specifically supports separate Shunting and Cruising use, and adapts well to
both small layouts and large
layouts that are scale-correct, modelled without compression!
As usual, the design has a full
User Manual (pdf, optimised for printing)
that explains its operation in more detail.
Three of these controllers have been installed in my N-clam layout,
expected to be completed by the end of 2005.
This controller has the following features:
- It controls motor RPM of a locomotive using the digitally-sensed back-EMF method;
- Low cost and low complexity makes it cheap and reliable;
- Shunt (center-off) and Cruise (anticlockwise off) modes to suit layout;
- Button-activated braking for realistic driving;
- Reversing at speed is impossible;
- Adjustable simulated inertia;
- Adjustable braking capability;
- Operational condition indication by flashing LED;
- Timeout mode to switch off unattended trains;
- Overload protection;
- Factory presets of control, inertia, braking and timeout interval
for Z, N, HO, O and G scales.
The PCB layout is shown at right and the
circuit diagram is below.
