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Discussion Starter · #1 ·
I'm seeking a simple block occupancy detector to use with DCC. I don't want a complicated unit that reports to
computers etc. Just need a circuit that will detect a loco (or rolling stock equipped with lights or resistors) in a block section.
The final output should be a set of dry contacts that can be used to energise a relay.
 

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Here's a couple of suggestions:-

Try LDT for either ready to use or a kit. Use this link to get direct to the English page of their website.

Or join MERG (website here) and buy their section detector kit.

I think both of these work on a current detecting principle, so are suitable for DCC only.

David
(MERG member but I haven't tried this kit yet)
 

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QUOTE (dwb @ 5 Aug 2008, 18:31) <{POST_SNAPBACK}>Here's a couple of suggestions:-

Try LDT for either ready to use or a kit. Use this link to get direct to the English page of their website.

Or join MERG (website here) and buy their section detector kit.

I think both of these work on a current detecting principle, so are suitable for DCC only.

David
(MERG member but I haven't tried this kit yet)

The LDT unit will only operate via a feedback bus so isn't suitable for a simple visual indicator. Typically for MERG they have several kits that do much the same job. I think the simple ToTI was designed for DC but will work with DCC, it is probably easiest to hook up to an indicator light but needs some complicated power supply arrangement. There is also the DTC8 about which I know very little, I use the LDT units rather than either of the MERG ones.
 

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Discussion Starter · #4 ·
QUOTE (Edwin @ 5 Aug 2008, 16:34) <{POST_SNAPBACK}>The LDT unit will only operate via a feedback bus so isn't suitable for a simple visual indicator. Typically for MERG they have several kits that do much the same job. I think the simple ToTI was designed for DC but will work with DCC, it is probably easiest to hook up to an indicator light but needs some complicated power supply arrangement. There is also the DTC8 about which I know very little, I use the LDT units rather than either of the MERG ones.

Thanks Guys, looks like the DTC8 would work but there is very little info on the MERG board, I assume that I have to join to learn more.

I have designed my own simple 3 aspect signalling system using small relays. I just need an occupancy decoder that will energise a relay that
triggers the colour light signal for that block.

I am using Lenz decoders to take advantage of its automatic braking capability, I believe that these decoders will transpond their position but I assume that means using a computer to run the whole show.
 

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QUOTE there is very little info on the MERG board, I assume that I have to join to learn more.

Well, they can't give away all their secrets


From what you've said, I think you would gain something from membership. If you don't want to take a "punt" on a year's subscription, you could visit the MERG stand at a show and talk to them the pros and cons of joining though it looks like Warley in December is the next chance to do so.

David
 

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Paul Hamilton aka &quot;Lancashire Fusilier&quot;
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I know Ricahrd at DCC Concepts has a product that does exactly that but I think it has 8 sections of occupancy however it is really simple to set up and requires no track cutting. I am sorely tempted down this path myself and may well buy one for a play.

QUOTE (fliermike @ 6 Aug 2008, 01:23) <{POST_SNAPBACK}>I'm seeking a simple block occupancy detector to use with DCC. I don't want a complicated unit that reports to
computers etc. Just need a circuit that will detect a loco (or rolling stock equipped with lights or resistors) in a block section.
The final output should be a set of dry contacts that can be used to energise a relay.
 

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QUOTE (fliermike @ 6 Aug 2008, 05:13) <{POST_SNAPBACK}>I am using Lenz decoders to take advantage of its automatic braking capability, I believe that these decoders will transpond their position but I assume that means using a computer to run the whole show.


The Lenz decoders have Asymmetric DCC for location specific commands like "Brake on DC" feature , so have the TCS decoders , that does not report the position of the loco to the system. But allows a signal to be sent to a block to control the loco - a command to enforce speed control through important sections of your layout or to stop a train in a siding, in the station, or before an occupied rail crossing.
I hope this helps
Regards Zmil
 

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QUOTE (Lancashire Fusilier @ 6 Aug 2008, 09:28) <{POST_SNAPBACK}>I know Ricahrd at DCC Concepts has a product that does exactly that but I think it has 8 sections of occupancy however it is really simple to set up and requires no track cutting. I am sorely tempted down this path myself and may well buy one for a play.

*** DCCconcepts does indeed have a detector that is simple to install and use.

Its frowned on to "self promote" (I agree with this policy by the way as too much commercial stuff will compromise the forums quality).

....As a direct comment has been made I will describe it here, however any specific questions re purchase should be direct to DCCconcepts or Euroscale (They have stock I think) or Bromsgrove models (their stock will be with them this week)

It uses Light dependent resistors for detection so needs no cutting of track or track circuits at all. It requires average room light to operate, however hidden or tunnel areas can still be used via installation of a superbight red LED to provide light.

Each detector of the 8 detectors on the PCB is independent of the others and has individual sensitivity adjustment. Each of the 8 has 4 operating modes which are set via a simple switch.

operating modes are
on only for the time the LDR is covered by stock or train
on for ten sceonds after LDR is covered by stock or train
on until next detector in sequence is triggered (not available on detector #8 as there is no "next" detector :)
on until ANY of the other detectors on the board is triggered.

It is not sensitive to wiring length and needs only light wire to connect sensors and any output devices.

Outputs will drive a mini relay or LED directly. it will also directly drive MASTERswitch.

There is a Sister product (quad relay board) available - this will drive directly from the detector using only two wires between them. It has 4 DPDT relays onboard.

Other details available by emailing me off forum at [email protected]

Regards
Richard
 

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QUOTE (Lancashire Fusilier @ 6 Aug 2008, 10:58) <{POST_SNAPBACK}>I know Ricahrd at DCC Concepts has a product that does exactly that but I think it has 8 sections of occupancy however it is really simple to set up and requires no track cutting. I am sorely tempted down this path myself and may well buy one for a play.

I have used those detectors from DCCconcepts. Work well under incandescent lighting as they are optical detection but they are not keen on flouro lights.
I had added hi-intensity Red LEDs (8000mCD) over the top of the sensors & all the time, they detected a blocking of the light by rolling stock but sometimes the internal 50Hz flicker of flouro lights would cause the sensors to start chattering.

This Pic gives an idea of what I was using. The Red LEDs are over the top of sensors loctaed in the middle of the track.


To recify the chattering, I had 2 options, completely cover the hidden trackage so external flouros would not give problems or change room lighting back to incandescent but as our Government is banning importation of such globes later this year in an attempt to phase them out, that was not practical now. Both options I did not like so I use a rail detection method.
 

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If you are getting into optical detection there are also detectors (from Heathcote Electronics I think) that bounce an infra-red beam off the bottom of the rolling stock. The big issue with optical is that they detect the presence of a train at a certain location, unlike the current detector which detects that there is no train in a section. Of course with current detectors, unless you just want to detect the loco you need to fit rolling stock with resistance axles.
 

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QUOTE (Richard Johnson @ 6 Aug 2008, 05:29) <{POST_SNAPBACK}>*** DCCconcepts does indeed have a detector that is simple to install and use.

Its frowned on to "self promote" (I agree with this policy by the way as too much commercial stuff will compromise the forums quality).

....As a direct comment has been made I will describe it here, however any specific questions re purchase should be direct to DCCconcepts or Euroscale (They have stock I think) or Bromsgrove models (their stock will be with them this week)

It uses Light dependent resistors for detection so needs no cutting of track or track circuits at all. It requires average room light to operate, however hidden or tunnel areas can still be used via installation of a superbight red LED to provide light.

Each detector of the 8 detectors on the PCB is independent of the others and has individual sensitivity adjustment. Each of the 8 has 4 operating modes which are set via a simple switch.

operating modes are
on only for the time the LDR is covered by stock or train
on for ten sceonds after LDR is covered by stock or train
on until next detector in sequence is triggered (not available on detector #8 as there is no "next" detector :)
on until ANY of the other detectors on the board is triggered.

It is not sensitive to wiring length and needs only light wire to connect sensors and any output devices.

Outputs will drive a mini relay or LED directly. it will also directly drive MASTERswitch.

There is a Sister product (quad relay board) available - this will drive directly from the detector using only two wires between them. It has 4 DPDT relays onboard.

Other details available by emailing me off forum at [email protected]

Regards
Richard
Hi
From what I understand, these detectors could or would, as soon as they detect a train, set off, say, a light signal or any other signal?
Would they set off a set of points?
 

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There are other block detector alternatives - NCE do the BD20 and Team Digital manufacture the DBD2, both of which will, I think, do what you want.

Regards

John R
Bromsgrove Models
 

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QUOTE (fliermike @ 5 Aug 2008, 17:23) <{POST_SNAPBACK}>I'm seeking a simple block occupancy detector to use with DCC. I don't want a complicated unit that reports to
computers etc. Just need a circuit that will detect a loco (or rolling stock equipped with lights or resistors) in a block section.
The final output should be a set of dry contacts that can be used to energise a relay.
If you're happy with DIY, as well as MERG, there is Rob Paisley's site http://home.cogeco.ca/~rpaisley4/CircuitIndex.html

AndreW Crosland
 

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QUOTE (ben100 @ 6 Aug 2008, 17:14) <{POST_SNAPBACK}>Hi
From what I understand, these detectors could or would, as soon as they detect a train, set off, say, a light signal or any other signal?
Would they set off a set of points?

*** Yes, that is correct - they can directly control signals and also with the correct interface, points.

I have a demo in my showroom which does both - it changes points to prevent overrun with he point set against a train, and changes signals at the same time. Several MRF members are currently using them with great success too!

BTW, to clarify Sols comment, my showroom has ONLY flourescents and there is no issue at all with any form of chattering or other problems - Sols problems are a combination of shielding of the LED from direct light by his backscene and the flourescents he is using, which are quite low powered.

Richard
 

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QUOTE (Richard Johnson @ 6 Aug 2008, 14:12) <{POST_SNAPBACK}>*** Yes, that is correct - they can directly control signals and also with the correct interface, points.

I have a demo in my showroom which does both - it changes points to prevent overrun with he point set against a train, and changes signals at the same time. Several MRF members are currently using them with great success too!

BTW, to clarify Sols comment, my showroom has ONLY flourescents and there is no issue at all with any form of chattering or other problems - Sols problems are a combination of shielding of the LED from direct light by his backscene and the flourescents he is using, which are quite low powered.

Richard
What sort of interface is needed for that?
Otherwise thanks,
Ben
 

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QUOTE (ben100 @ 6 Aug 2008, 21:27) <{POST_SNAPBACK}>What sort of interface is needed for that?
Otherwise thanks,
Ben

***MASTERswitch, MASTERswitch V2 or MASTERswitch PLUS, with a small optoelectic interface that we will provide at no charge to MS users for this sort of application.

Its purpose is to turn the output of any form of detector into a simple switch command, and it does it nicely, needing only one negative output from the detector daisy chained to all MASTERswitch, with the positive wire (s) then connected to the point direction that is desired.

In our demo setup for example, we use two of the LDR sensing devices placed between the rails on the heel sides of the points in a crossover, these are both connected to a single channel of the detector board. This channel is then connected to the MS controlling the points via the OPTOelectic interface (its just three wires in, 3 out).

When either sensor is triggered, the crossover changes to "straight" therefore preventing derailments automatically.

Richard
 

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QUOTE (Richard Johnson @ 6 Aug 2008, 15:22) <{POST_SNAPBACK}>***MASTERswitch, MASTERswitch V2 or MASTERswitch PLUS, with a small optoelectic interface that we will provide at no charge to MS users for this sort of application.

Its purpose is to turn the output of any form of detector into a simple switch command, and it does it nicely, needing only one negative output from the detector daisy chained to all MASTERswitch, with the positive wire (s) then connected to the point direction that is desired.

In our demo setup for example, we use two of the LDR sensing devices placed between the rails on the heel sides of the points in a crossover, these are both connected to a single channel of the detector board. This channel is then connected to the MS controlling the points via the OPTOelectic interface (its just three wires in, 3 out).

When either sensor is triggered, the crossover changes to "straight" therefore preventing derailments automatically.

Richard
Where on the DCCconcepts site does it mention that? I don't seem to be able to find it anywhere?
 

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I would like to clarrify what Richard said about my installation

BTW, to clarify Sols comment, my showroom has ONLY flourescents and there is no issue at all with any form of chattering or other problems - Sols problems are a combination of shielding of the LED from direct light by his backscene and the flourescents he is using, which are quite low powered.

We has worked together on a lot of initial testing of these units & found that I did need a lot of additional direct lighting as I only was using 18w flouros partially over the sensors, not the normal 36w types. The sensors were as the photo indicates, partially blocked from the rest of the room lighting & I found that even if I stood up & created a slight shadow, some times chattering would occur.
My 20x12 ft layout room has 2 overhead lighting circuits - for normal operation, 4 x18W with one in each corner & long 6ft fluoro across the middle while for construction, I also switch on 2 sets of 36w units making an additional 144W & under this circumstance I hadno problems. If my storage were completely covered, the one Red LED was adequate as external light frequency could not affect the sensors combined with the LED light.

Let me state that they do work , it was the situation that I was trying to make them work was not a normal situation & perhaps I should have perservered.

I intend to do is to use 2 Hi-intensity Red LEDs per sensor, that I know works, not just the one 8000mCD that I had previously used.
 

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QUOTE (ben100 @ 7 Aug 2008, 03:02) <{POST_SNAPBACK}>Where on the DCCconcepts site does it mention that? I don't seem to be able to find it anywhere?

*** Hi Ben, it doesn't - the website is sorely in need of refreshing. If U send me a direct email to [email protected] I will send you the instructions as a .MDI file (Microsoft document imaging) or PDF (PDF is a large file though)

Richard
 
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