Electronics SIG Zoom meeting 27 February 2025

[Hugh Norwood]

Notes from the Electronics SIG Zoom meeting 27 February 2025

Seven members attended
Tom Alexander, Dave Cooper, Stephen Elliott, Chris Odell, Stephen Raisnbury, Jeffrey Sydenham, Hugh Norwood

Graeme Dunbar sent apologies.

Stephen E has been working on Dizzy Heights; he has received a lights sequencer (from Kytes Lights) to light up the underside of the overhead track.

Dave has been experimenting with a breadboard (the electronics kind!) to build a sine wave generator – and was pleased to see it works. It sparked a debate on sound on layouts – a couple of us have background sounds, Chris has sound-fitted locos and is looking into adding sounds effects on his layout. I think we all agreed that it should not be obtrusive, especially if out on show.

Stephen R has had a "stocktake" and has a quantity of old Raspberry Pi's and Arduinos.

Chris asked what might be suitable for a project for his layout – PicAxes or Arduinos. The discussion concluded that it was horses for courses. He is also looking into lights to go into signals – it was suggested pre-wired "nanoLEDS" were probably to way to go.

Although he had nothing to report on electronics, Tom has been looking into putting lighting into coaches and vans; either picking up current from the track or using button cells – these would be switched on and off via DCC.

Chris wondered whether a track-powered rear-end light could be used to detect the rear of a train – by the current draw.

We wound the meeting up as it was getting late, but pencilled in April 10th as the next meeting.


HN 2 April 2025

[Graeme Dunbar]

Thanks Hugh. Sorry I could not make it.

Regarding tail end detection using current draw by an LED in a brake van - most certainly. I have an N gauge layout that uses that. Surface mount resistors connected between wheel rim/tyre and axle also work. I tried conductive (i.e. resistive) paint too, but it was difficult to achieve a suitably consistent resistance. Many black paints are slightly conductive as they contain carbon black.

One limitation (in DC) is the need to have track power in order to detect a train. I experimented with a  high impedance AC signal as a source, but stalled trying to reduce cost and complexity.