Search found 212 matches

by Gordon H
Mon Jul 03, 2017 1:30 pm
Forum: DCC Forum
Topic: DCC Point Controller?
Replies: 29
Views: 2935

Re: DCC Point Controller?

It is purely the impression their site gives me. I can understand them not wanting to "give away" instructions and so forth but it does not inspire confidence in prospective members when you have to join to find out further information on whether the product is compatible with a main manu...
by Gordon H
Mon Jul 03, 2017 1:07 pm
Forum: DCC Forum
Topic: DCC Point Controller?
Replies: 29
Views: 2935

Re: DCC Point Controller?

A friend of mine is a member of a MERG group in Leicestershire, he is one of their "elves" who assembly modules bought by other members. I don't know if this is practised in other MERG groups. For clarification, the MERG kit 'elves' don't actually assemble modules, they collate all the bi...
by Gordon H
Wed Apr 12, 2017 12:34 pm
Forum: General Model Railway Discussion / News
Topic: Curve dimensions
Replies: 5
Views: 886

Re: Curve dimensions

Flashbang wrote:Note; all radius stated are to the centre of the track. So for a 180 degrees curve you'll need to add at least a further 25- 30mm to the overall width.

And don't forget to include the overhang of the coaches on the outside of curve, which if they are scale length Mk3s will be considerable too.
by Gordon H
Wed Mar 29, 2017 11:07 pm
Forum: Electronics
Topic: Using 7805s in parallel
Replies: 17
Views: 2490

Re: Using 7805s in parallel

Was thinking of getting the 5v 5A as this was what the Altai was capable of. If you intend to continue with this approach, it would be easier to use an LM338T instead of multiple 7805s as it provides up to 5A @5V in a single TO-220 device. However, the requirement for extensive heatsinking still ap...
by Gordon H
Thu Mar 23, 2017 12:46 pm
Forum: General Model Railway Discussion / News
Topic: Preamble DCC length
Replies: 3
Views: 569

Re: Preamble DCC length

As I recall when I built my own command station (some 19 years ago - frightening!) , some of the decoder programming modes use rather more than 10 preamble bits, so you may need to include the capability to send higher numbers of them anyway, especially if you plan to include CV programming with you...
by Gordon H
Tue Mar 21, 2017 1:05 pm
Forum: Electronics
Topic: Block Signalling Module
Replies: 12
Views: 1549

Re: Block Signalling Module

Regards the lighting I have fluorescent fittings so it could be these interfering with the infra red detector. Also the signal & sensor are at the other side of the layout from the window. The ASP1A module instruction sheet suggests its detection method should be immune to local lighting condit...
by Gordon H
Mon Mar 20, 2017 12:40 pm
Forum: Electronics
Topic: Block Signalling Module
Replies: 12
Views: 1549

Re: Block Signalling Module

Bufferstop wrote:I'd expect it to work better from a piece of dark plastic...

And you should also be aware that what looks dark to the human eye may not be quite so dark at the IR wavelength being used.

BTW, what particular make of 'Block Signalling Module' is being discussed here?
by Gordon H
Wed Feb 15, 2017 12:26 pm
Forum: Electronics
Topic: Power supply for idiots
Replies: 5
Views: 1214

Re: Power supply for idiots

The amount of current capacity required is likely to be almost entirely dependent on the number of servos you connect to it.
Presumably the 2A rating suggested is based on the worst case, i.e. all servos fitted.
by Gordon H
Wed Feb 01, 2017 12:50 pm
Forum: DCC Forum
Topic: connecting capacitor to decoder
Replies: 16
Views: 2450

Re: connecting capacitor to decoder

You can connect a stay-alive to any decoder its just a case of finding the positive junction in the bridge rectifier on the chip and then picking up a negative. If anything, the positive junction should be easy, because it will have the blue function supply wire attached. Finding a convenient negat...
by Gordon H
Wed Jan 18, 2017 1:05 pm
Forum: Personal Layouts - Under Construction
Topic: MY NEW LAYOUT ARDUINO CONTROLLED
Replies: 231
Views: 21589

Re: MY NEW LAYOUT ARDUINO CONTROLLED

End2end wrote:One thing that is really puzzling me is how to mount a SG90 servo under my basebaord vertically so I can swing a gate.

As is often the case, MERG have a kit available for that purpose (see Kit 690):
http://www.merg.org.uk/kits.php#sect30
by Gordon H
Tue Nov 22, 2016 12:32 pm
Forum: Electronics
Topic: LED wiring on mimic panel
Replies: 19
Views: 3370

Re: LED wiring on mimic panel

Quick question. Can I use a variable resistor like a dimmer switch for the whole panel so I can set the brightness? As has been said, it would be tricky to use just a variable resistor. Even a variable voltage supply is unlikely to give the desired effect of proportional dimming in all cases. The b...
by Gordon H
Sun Nov 13, 2016 7:11 pm
Forum: Electronics
Topic: new idea for long range photo detectors in non-scenic areas
Replies: 16
Views: 1911

Re: new idea for long range photo detectors in non-scenic ar

I actually found the threshold current of the diode is around 10-12mA and this is guaranteed with 3v3 operation but not 3V. However operating these lasers at the specified 5V increases both the current and heat load substantially without much of an increase in light output... Hardly surprising real...
by Gordon H
Wed Nov 09, 2016 12:47 pm
Forum: Electronics
Topic: new idea for long range photo detectors in non-scenic areas
Replies: 16
Views: 1911

Re: new idea for long range photo detectors in non-scenic ar

I suspect these Lasers are not meant to be used in CW mode for any length of time. They would probably last a lot longer if a pulsing regime is used instead.
by Gordon H
Sun Nov 06, 2016 7:32 pm
Forum: Electronics
Topic: new idea for long range photo detectors in non-scenic areas
Replies: 16
Views: 1911

Re: new idea for long range photo detectors in non-scenic ar

Hi Gordon, yup there just 3mW and I reckon once in position impossible to look into anyway but yes your points worth making especially to peeps who have not used lasers before :) If you are operating them in CW mode, 3mW is well over the limit for Class 1 & Class 2 visible Lasers (see http://ww...
by Gordon H
Sun Nov 06, 2016 5:48 pm
Forum: Electronics
Topic: new idea for long range photo detectors in non-scenic areas
Replies: 16
Views: 1911

Re: new idea for long range photo detectors in non-scenic ar

Comments including done it before or will never work very welcome :) I assume you will now be putting a Laser warning label on your layout? Are these Laser diodes eye-safe? What 'Class' do they fall into - hopefully no higher than 'Class 1'? Not trying to put you off, but once Lasers are involved q...

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