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Speedometers...what are you all using?

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  • Member since
    August 2005
  • From: Tacoma, WA
  • 847 posts
Posted by ShadowNix on Sunday, April 27, 2008 9:57 PM

Sorry if I was not clear in my last posts... I have DCC (NCE Powerhouse Pro)

Brian

"That which doesn't kill you makes you stronger!"
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Posted by mike_ruby on Saturday, May 3, 2008 1:34 PM
I've found out how to post photos, so here are some of my speedo car.


This shows the reed switch


This shows the bare car with the speedo installed


This the completed car, still to be painted.

Mike Ruby
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  • From: Tacoma, WA
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Posted by ShadowNix on Saturday, May 3, 2008 1:55 PM

Wow, mike...NICE!!! Again, do you remember what article/year?  I will have to find that article!  Man looks really nice.  Is the meter on the L for the weight/drag?

Brian

"That which doesn't kill you makes you stronger!"
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Posted by stan2004 on Monday, May 5, 2008 10:48 AM

I custom-built a wireless speedo not so much for tuning CVs, but to monitor consist speed in real time. The sensor used the optical interrupter wheel method with many evenly-spaced holes around the circumference.  The wheel is limited in size by needing to clear turnouts or grade crossings but maximum holes were needed to get good resolution at slow speeds.  The flatcar is powered by 3 AAA batteries and transmits the data over RF.  The receiver displays scale MPH or can switch to an odometer for elapsed distance.  An RS-232 output in the receiver sends info in real time to a PC such as for data logging or plotting speed vs. time. 

My eventual goal, if I ever get to it, is to integrate this into a car located behind the tender with a strain gauge to measure ounces of drawbar pull.  Combined with the speed data, I could watch scale Horsepower in real-time just like the prototype dynamometer car.  I haven't worked on this for years now and see that superior wireless methods are now more readily available - custom-built stuff just takes too much effort.  Bluetooth modules with their tiny antennas would fit completely in a car whilst I used the FM radio band which required longer antennas for good range.  A few years ago it seems someone (Walthers?) introduced some kind of wireless measurement car and maybe there's something that could be used from there.  IIRC a shoe company (Nike?) came out with a shoe sensor that transmitted running data to a watch for display.  Combining the bicycle speedometer with something like that would be a neat DIY project. 

 

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Posted by mike_ruby on Sunday, May 11, 2008 7:39 AM
Sorry I'm a bit slow replying, but I don't receive reply notification from the forum (yes its is selected, but emails don't get to me).

The article was in RMC Sept 2006.
The left meter is the draw bar pull meter as fitted as standard in these Walthers cars. The marks are about 1oz of pull apart.

Mike Ruby
  • Member since
    August 2005
  • From: Tacoma, WA
  • 847 posts
Posted by ShadowNix on Sunday, May 11, 2008 2:49 PM

Thanks... I found that out and have the 2006 Sept RMC being mailed to me.... I will document my progress if I have time!

Brian

"That which doesn't kill you makes you stronger!"
  • Member since
    June 2002
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Posted by IDAHOSURGE on Saturday, July 5, 2008 12:24 PM

ShadowNix,

I was wondering if you bought the speedometer car from CP4E and if you did what do you think? 

Rod

 

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  • From: Brisbane Australia
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Posted by Alantrains on Sunday, July 6, 2008 6:56 AM

One simple speedometer is to use a bicycle speedometer, I bought mine at Big W (like Walmart) It has a small LCD display with 2 buttons and a remote wired reed switch. You're supposed to put a magnet on the bike wheel and it counts the revolutions and using the wheel diameter or circumference calculates the speed. Just use the scale wheel diameter in the calculation the speedo askes for when you set it up. Use the magnet and reed switch supplied with the speedo or maybe a smaller magnet on the axle of an old freight car. the whole thing fits in a box car if you're modeling in HO and is sufficiently accurate for most things.

cheers 

Alan Jones in Sunny Queensland (Oz)

 

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Posted by mike_ruby on Sunday, July 6, 2008 7:59 AM
Walthers were going to make the wireless readout, but in the end dropped it. It would have fitted into their dynamometer car, the same as I used for my speedo car, see earlier in this thread.

I've tried a wireless bicycle speedo, but found it doesn't have much range, I plan to play with it a bit to see if I can increase it.

Mike Ruby


A few years ago;it seems someone (Walthers?) introduced some kind of wireless measurement car and maybe there's something that could be used from there. IIRC a shoe company (Nike?) came out with a shoe sensor that transmitted running data to a watch for display. Combining the bicycle speedometer with something like that would be a neat DIY project.
  • Member since
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  • From: Franconia, NH
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Posted by dstarr on Sunday, July 6, 2008 11:00 AM
 wjstix wrote:

You can do it by timing the train as it goes around the layout. My last layout's continous run loop turned out to be very close to one scale kilometer in length, so it was easy to work out speeds in KPH (If at train took 1 minute to go around the loop, it was going 60 KPH; two minutes = 30 KPH etc.) and then convert that to scale MPH's.

BTW an easy way to measure your mainline is to make up a train of cars and juggle the cars of varying length around until you come up with a train that is say 3' long. Then you can push the 'train' around the layout one trainlength at a time until you've gone all the way around the layout. Then multiply the number of trainlengths by 3' or however long the train is. That way, you don't have to try to use pi to calculate the curved tracks. Once you know how long the mainline is, it's pretty easy to convert that to scale miles, and then to calculate how fast a train is going if it takes x amt of time to go around the layout once.

Of course, you can just mark of a shorter distance on the layout and do it that way, but the longer the 'sample' is you take, the more accurate the result will be.

Ruler and stop watch, works for me.  I measured the length of the mainline with an ordinary steel tape measure (bends around curves).  Convert from inches to miles by dividing by 12 to make it feet, and then dividing by 5280  to make it miles.  Multiple by 87 to make it HO scale miles.  Convert seconds to hours by dividing by 3600.   For extra accuracy time a couple of loops around the main line.  If you don't get the same (or nearly the same) time, you have a measurement problem.  

 

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Posted by mike_ruby on Sunday, July 6, 2008 1:17 PM
 dstarr wrote:

Ruler and stop watch, works for me.  I measured the length of the mainline with an ordinary steel tape measure (bends around curves).  Convert from inches to miles by dividing by 12 to make it feet, and then dividing by 5280  to make it miles.  Multiple by 87 to make it HO scale miles.  Convert seconds to hours by dividing by 3600.   For extra accuracy time a couple of loops around the main line.  If you don't get the same (or nearly the same) time, you have a measurement problem.  

 



That's great if you have a simple loop. To do a continuous run my locos would have to go three times around the room, up and down 2.5% - 4% grades and around numerous curves.

I'm working on a rolling road speedo. The rolling road is built, the difficult bit is picking up the speed from the rollers. I have an optical detector working, but not reliable enough yet.

For now the speedo car is still my best way.

Mike Ruby

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