LCount, Octal Wheel/Axe counter for LocoNet

Content → Hardware → MGV

• The MGV Family

LocoNet is a trademark of Digitrax, Inc.

In the real world, the most used way of train detection is done by a so called wheel or axle counter.

This counter is a magnetic system, positioned between the rails and close to it.

Mostly there are two, one on each rail.

A passing wheel will be detected, and in this way a passing amount of wheels is counted.

Entering the next block, the wheels are counted again, and if the amount is the same as previous, the previous block can be entered by a following train.

This is a rather simple explanation of what is happening in the real world, but is gives some idea how it is done.

See also http://www.prt-inc.net/php/wdServ.php

This magnetic system is hardly possible in model railroad.

The most important reason for that is that many wheels are made of non-iron materials or even some kind of plastic.

So here we are going to use an Infra Red gate to make it work.

The sensor is placed somewhere outside the rails, the distance can easily be between 10 - 200mm, which makes it very easy to hide it somewhere,

in buidings, or anything anyone can to fantasy about.

The transmitter, an IR-led, (SMD type), is situated between the rails, about 2 mm from either left or right rail, and facing to the rail.

If the led is placed on top of a legger, the top of it will be just level with the top of the rails.

This avoids that any locomotive or waggon will touch the transmitter.

The transmitter sends an infrared beam that has a radiation angle of 20 degrees.

Because the transmitter is more or less 'hiding' itself behind the rails, the receiver must be positioned slightly higher in a way that the angle from

transmitter to reciever is approx 10 degrees or less.

This avoids that low hanging parts of mostly steam loc's are also blocking the IR Beam.

All we are interested is wheels. And because the beam is very low over the rails, anything that is > 1 mm above the rails, will be ignored.

As seen on the picture below, the test is setup with Maerklin C-rail, meaning that the loc is equipped with the ugly slider.

This slider can pass the transmitter without any problem.

The combination of transmitter and reciever is the same as used for MGV133, exept for the SMD shape of the transmitter.

8 Counters can be connected to the unit.

The unit is connected directly to the LocoNet with the same connetors as standard for MGV-LocoNet units.

No additional MGV50 is needed.

Rocrail will be adapted with settings, to handle this unit, and using this wheel number information as an extra safety guard for freeing a block.

A block can only be given permission for new entrance when all wheels are counted in the following block, so no waggons are lost!

This will turn out to be the most reliable system to avoid collision with lost waggons.

No other system is known, that can give this 100% guarantee!

Also for fiddling and sorting waggons this unit will give an extremely nice solution.

Please keep yourself updated by coming back here!

The sensor needs to be mounted slightly higher then the IR led. The angle from horizontal position should be approx 10%

The distance can vary between 50 and 300 mm as lomg as the angle is taken into consideration.

With bright daylight, the distance should be no more than 50 mm.

It is very important to avoid that the IR beam can pass under the rails.

Therefore like on the picture the best position is on top of the legger.

Be sure that top of the IRled is not higher than top of rail.

In that way, nothing under trains or waggons can hit it.

Distance between IRled and rail should be close to 1.5mm.

Tge IR beam where we are interested in, is only passing approx 0,5mm over the rail, in an angle of 10 degrees elevation.

In this way, only wheels are seen, nothing else.

Development is still going on, but here is the first start of hardware files…

The schematics

The PCB and parts positions