HO scale operating Detector

[thaddeusthudpucker]

Here's one for you guys...

I want to make a thingy that will actually count axles. Assuming that all of my cars have metal wheelsets, how could I make a device that would "count" them and then cause a recording to play audibly, as in a detector. It would be helpful in a helix about midway up to verify that everything is still on the rail. This is for HO scale.

 

[diburning]

It's actually very hard. Most of the detectors I've seen for model trains involves a custom PC program.

I can't think of any way for any mechnism to count metal axles as they are non-magnetic, and do not draw any current since they should be insulated.

 

[Rico]

I'm thinking of that as well for my staging.
Looking into an infrared beam that would cross the railhead, the number of times the beam is broken would count the axles. A 'puter whiz friend thinks he can rig it.
Dragging equipment detectors should be easy, foil between the rails that conduct when a metal wheel bridges the gap and sets off the buzzer or recording.
Oh I'm sure it's much more complicated but I'll wait for you to figure it out before I do mine.
See... easy!

 

[MGWSY]

Here you go even though its a tad expensive.

http://www.advice1.com/twistedtrains/hotboxdetails.html

 

[tankist]

for the detection portion i would go with metal wheel shorting a gap between rails. in simplest form its two immediate gaps making very short ~1mm or so of un powered section serving as one of the contacts. or perhaps a wider gap with electrode in between. the rest is some sort of PC software

 

[bkpigs]

Tanks idea is what I was thinking. If you gap one side of the dectection rail say the width of a Dremel blade or something, when the metal wheel bridges the gap it will cause a short. The only thing you will need to be careful on is the otehr end of the dection rail. You will need to use an insulated rail joiner (plastic ones with spacing) and still leave a little room between it so it does not make "false shorts" on the detection rail, causing the count of axles to be incorrect.

Another idea would be to have a small wisker switch that would make contact with the rail every time a wheel goes over it.

The computer stuff will have to be left for someone who knows that better than me.

 

[John P]

The Twisted Trains detector looked interesting, but the website says

"***Due to lack of interest this product is no longer for sale ***"

 

[tankist]

Tanks idea is what I was thinking. If you gap one side of the dectection rail say the width of a Dremel blade or something, when the metal wheel bridges the gap it will cause a short. The only thing you will need to be careful on is the otehr end of the dection rail. You will need to use an insulated rail joiner (plastic ones with spacing) and still leave a little room between it so it does not make "false shorts" on the detection rail, causing the count of axles to be incorrect.

the problem with only one gap is that both sections connect to same power supply/DCC bus (even if between isolated power sensing sections) and always connected. as such you have the gap shorted anyways.

 

[MGWSY]

The Twisted Trains detector looked interesting, but the website says

"***Due to lack of interest this product is no longer for sale ***"

If you EMail them they will make you one as that is what I did asking if its still available.

 

[bkpigs]

the problem with only one gap is that both sections connect to same power supply/DCC bus (even if between isolated power sensing sections) and always connected. as such you have the gap shorted anyways.

What I was trying to say is that there would be a section not powered and used to detect the short. On one end there would be just a cut gap to allow the short to happen. On the other you would need an insulator of some sort (plastic insulated railjoiners) that would not cause a short. It would look like this ~~~~[]----l~~~~ with the ~ being powered, [] being the plastic rail joiner, - being the detection section, and l being the gap for the short. Of course the detection section would have to be fairly short so the locos don't lose power and such.

 

[Steamfreak]

Here's a circuit that would work....
The +/- are a power source (whatever your detector requires). The shaded rectangle is your detector. The circuit would close when a wheel bridges the gap between the right hand rail and the center section. The center section could be really short...whatever you might require to solder a wire to it.

Of course, you would still require the software to make sense of your detector's output....

P.D. Pardon the drawing...I suck at Paint and such programs....