SPEEDOMETER

[Lester Perry]

I ran across plans for building a speedometer for MRR using a Cyclecomputer for bicycles <!-- m --><a class="postlink" href="http://www.members.optusnet.com.au/nswmn1/Speedo.htm">http://www.members.optusnet.com.au/nswmn1/Speedo.htm</a><!-- m --> Does anyone know anything about this?

[P5se Camelback]

Sorry, Lester ...

Math and Electrical Stuff are my two worst things in life to have to deal with.

I didn't know that when I became enamored with trains as a four or five year old!

[Sumpter250]

Matching loco speeds..... I used to run a 40 car coal train, on the club layout, with a Spectrum 2-8-8-2 on the head end, and another at the back end pushing. Once I had the engine speeds set, I would watch the couplers in the middle of the train, and manually adjust the pusher's speed to keep the mid train couplers at minimum strain. This worked well through all the up and down grades, and I never had a problem with any part of the train, even through several hours of operation.
It did help, that I was using a Digitrax DT400 throttle, that allowed me to increase, and decrease train speed ( both locos, almost simultaneously ), and also let me know where each one's speed was set, so I could keep the pusher well within the speed range of the lead.
I understand the convenience of matching loco speed through CV adjustments, but when the lead is downgrade, and the pusher is upgrade ( or vice-versa ) one or the other loco has to be sped up, or slowed down to maintain relatively equal tension throughout the train.
I guess the short version is; My boat doesn't float in "Gadget Bay "...or... The engineer in the helper, has to " work for his pay " . :|

[rrinker]

For steam, or pushers on the back, manual is the only way to go - that's the way it was done, anyway. For multiple unit diesels all ont he front though, even the real thing runs them all from oen cab. So some speed matching is required. However, I think since we now have all sorts of twqeaks with DCC, we tend to go overboard on just how matched they have to be. It does NOT have to be perfect, it jsut has to be close. People are goign nuts with usign speed tables so that the locos are exactly dead on at every single speed step - t's really not required. We ran two or more locos together using DC, and there was really no way to adjust speeds at just parts of the control range - one that ran too fast you could slow down with some diodes, but you couldn;t have that work at different parts of the throttle band (ok, being am EE I can think of some rather complicated circuits that COULD do that in plain DC - but let's not go there). Yet everythign worked fine. DCC is no different - as long as they are close so one isn't actually dragging the other, locos will work fine in consist. While a fancy speedometer is a nice gadget, and I suppsoe just about any self-respectign gadget freak probably ought to have one, it's certainly not necessary for speed matching locos. What is IS good for is showing peopel just how fast they are running - most people tend to run their models far too fast. Like that 100 car coal drag whooshing past at 80 per... umm, maybe on a downgrade if the brakes have failed. Case in point, exaggerated speeds in the movie Unstoppable - most people have no idea about trains, so they had to use something more like car speeds - 70, omg that's fast! It wouldn't have seemed as impressive if they had the train getting up to the breakneck speed of 40mph.

--Randy

[Lester Perry]

I am not looking for speed match. I just thought it was neat. I think I have it figured out. I just need to remember how to find the circumference of a wheel. I think it is pie times R square. Now what is pie and how do I figure out R square. It has been too long since school.
Actually this is very easy and inexpensive to build. I have spent less than $10 and have it built. All I need to do is calibrate it.

[torikoos]

A bit like a modeling friend of mine has done perhaps?

Here's his youtube footage about it:

<!-- m --><a class="postlink" href="http://www.youtube.com/user/mikerubynfs#p/u/14/kPLiJyZ21fk">http://www.youtube.com/user/mikerubynfs ... PLiJyZ21fk</a><!-- m -->

Koos

[Charlie B]

I am not looking for speed match. I just thought it was neat. I think I have it figured out. I just need to remember how to find the circumference of a wheel. I think it is pie times R square. Now what is pie and how do I figure out R square. It has been too long since school.
Actually this is very easy and inexpensive to build. I have spent less than $10 and have it built. All I need to do is calibrate it.

Les, it is Pi * diameter. Pi R squared is area of a circle

[P5se Camelback]

Yes, I thinks Charlie B. has it nailed! And I'm pretty sure that Pi = 3.1417

But for any of that diameter and circumference stuff, I have to refer to my "Machinery's Handbook" ... the book that is so important, there's a drawer sized just right for it in the middle of my Kennedy Machinist's Tool Box that got when I first graduated from design school to keep all my model building tools in, including my copy of the handbook, I mean, why not ... it's got its own drawer!

[Lester Perry]

A bit like a modeling friend of mine has done perhaps?

Here's his youtube footage about it:

<!-- m --><a class="postlink" href="http://www.youtube.com/user/mikerubynfs#p/u/14/kPLiJyZ21fk">http://www.youtube.com/user/mikerubynfs ... PLiJyZ21fk</a><!-- m -->

Koos

Nothing that elaborate. This is a car to be pulled on the track. I would have a pic of it but I just broke it,turned off the lights and walked away. Try again tomorrow.

[Lester Perry]

Alright guys here it is. Now don't be too mean to me. I know you have been getting impatient.













Keep calm now Ready 5...4...3...2...1...scroll down now

[Lester Perry]

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Hey this is my thread I can do what ever I want. Good bye

[faraway]

I am using this little set sold by Conrad (part number 248718 - 62) in Germany since years
The little PCB is put on a gondola or flatcar with a battery and sensor at a wheel set. The speed is transmitted with the three LED to the black box you keep in your hand. The speed is displayed in km or miles per hour. The PCB has some jumpers to set the diameter of the wheel of the flat car. It works without trouble since years.

ps. I have an older version without the power supply. My black box needs another battery.

[Lester Perry]

That sounds like it works like mine,except yours transmits to a receiver so you don't have to follow it around

[Ralph]

Dang Les!!! That's CLEVER! It would be an eye catcher to watch go by!
Ralph

[Lester Perry]

I can't take credit for it. That is how this thread got started I saw it somewhere else. I am not sure of accuracy yet, my railroad is out of service right now. Hope it will be up in about a week. I sent my DCC system out for software upgrade. I know it works as I can push it around the track and get a reading, but I can't calibrate it pushing it by hand. This thread has got me thinking though. How much speed is lost on a grade or picked up.