Maximum length of a small 9g servo wire

I have run 25 feet using Cat5e fixed (single cores) cable.

The cable was LSOH (as I had lots of 'ends') and was run in buried garden hose.
Connectors, and final wiring, were enclosed where possible. - To protect from UV.

If I wanted to run any further, or multiple signals, then I would consider using balanced line-drivers.


It was a 'proof of concept'. But did work.
The final solution was a signal box (appropriate) was used to house a receiver, battery, solar charger.
The receiver, servos, etc. were turned off between sessions. The solar / battery system was 'always on'.

PhilP
 
Hi Phil, It would be around 50-60 feet. But on my travel's i see they do a cat5-6 extender, so will look into these. "Up to 30 metres & 4 servos"
I get the impression the power is ok, but the signal can get interfered with & servos not stopping where you like them to.
servo extender.jpg
 
I would also suggest using so-called 'waterproof' servos, rather than the cheap knock-offs..

PhilP
 
This is how I did my servo controlled points
ringbalin-light-railway.blogspot.com

Servo Controlled Points Part 1 (Now Redundant but still Relevant)

This is now redundant because of the layout re-configuration but the servo testers will be re-purpose in other locations in the future Bec...
ringbalin-light-railway.blogspot.com ringbalin-light-railway.blogspot.com
ringbalin-light-railway.blogspot.com

Simple Inexpensive Servo Controller

This is a direct copy of the article that is on Dave Bodnar's website "trainelectronics.com". Nothing has been changed and copyright is owne...
ringbalin-light-railway.blogspot.com ringbalin-light-railway.blogspot.com
The longest power run is about 10 metres but longer ones are planned for the future.
I am using old telephone cable (4 core solid copper) for the power but put my controllers near the points.
 
Or,
If you run a 3/4 pair cable, you could have a bus for the control, and have addressable devices to control signals and points..

PhilP
 
If you already have a DCC system you could run a power bus from it and use something like an ESU Switchpilot Servo in your waterproof container/building to control 8 servos switches. It will drastically simplify the configuration and wiring in your example, gives you wireless control of the points, and can also be automated through the central station and PC. The extension relay modules would allow you to install the Red/Green LEDs as well.

I use these units on my and club's layout to control loco shed doors.
 
collectors said:
Hi Phil, It would be around 50-60 feet. But on my travel's i see they do a cat5-6 extender, so will look into these. "Up to 30 metres & 4 servos"
I get the impression the power is ok, but the signal can get interfered with & servos not stopping where you like them to.
View attachment 323376
Click to expand...
Thanks for the info on these - not seen them before.

I have bought a couple to reverse engineer. I have a rough understanding of how it works but I want to know - lets see how they do it!
 
collectors said:
I get the impression the power is ok,
Click to expand...
you want to be sure that the power is oke.
Take or borrow a decent multi meter, and make sure there is NO voltage loss.
Calculate also the wire resistance after measuring it, the Calvin method will be best suited for this.

If both are in correct order and your signal is hertz based (bit out of my league here) try to amp it up.
A bit faster crystal sould do the trick, or a slightly higher v
Both will make sure that the signal is getting there stronger and quicker.

You could also try a heavier opamp or a bigger capacity condensator in the transmitting device (knowledge of 40 years ago! get a second opinion)

With best regards Igor

ps for calculating your cables use this one:
www.omnicalculator.com

DC Wire Size Calculator

Use our DC Wire Size Calculator to know the wire size needed for your DC electric application.
www.omnicalculator.com www.omnicalculator.com

set temp to 40c and v drop to 0.5%
 
On the diagram the 2 boards "Wifi & servo throw" have 2 green wires that link a relay to a push test button. I had a spare drum of cat5 with about 90m & connected via this cat5. Hay presto it worked. So i am assuming this is not a voltage switch, but a negative switch, as i dont think 5v would of reached 90m. But hayho, i got a servo to work at 90met. "How long will it last?" lol
single-points.JPG
 
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How long will it last?
Depends if it has power on it 24/7 and gets damp..

I have had things die in months. - Copper tracks migrated, due to constant power and damp.
There again, had a home-brew solar light setup, which lasted six and a half years. - Same cells, wire-rot in the end.

PhilP
 
PhilP said:
How long will it last?
Depends if it has power on it 24/7 and gets damp..

I have had things die in months. - Copper tracks migrated, due to constant power and damp.
There again, had a home-brew solar light setup, which lasted six and a half years. - Same cells, wire-rot in the end.

PhilP
Click to expand...
Its going to be well protected, but i know what you mean. The Tupperware boxes i have found better than a lot of electrical boxes & this will have a Kippo shed covering the box. I also pop one or two Silica gel sachets in the box & found them to be very good. "The damp absorbers that look like tea bags"
 
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