I'm builing a test switching layout that will eventually be a part of a larger layout. I want to use caboose hobbies switch machines for single turnouts and Tam valley servors for crossovers. I want an easy functional crossover that is pretty much plug and play plus at a lower cost than a tortoise setup. What do I need to order from Tam Valley? I will not be controlling turnouts with DCC. Thanks!
Just the two servos as far as I can see.
https://www.tamvalleydepot.com/products/servosaccessories.html
Plus a double pole double throw toggle switch to act as a reversing switch to provide reversing DC power to drive the servos. Maybe their DY-5001 DPDT relay would make wiring the servos easier?
If you are powering the frog you would get the servo model with the add-on snap-switch.
Good Luck, Ed
https://www.tamvalleydepot.com/support/crossovers.html
Thanks Ed! I very new to this...
Seems to me that I would need the following (but clearly could be wrong):
2 Singlet servos,
1 fascia controller (FCB020),
1 recessed fascia mount MFC3D1
1 y-cord to operate both turnouts with a depressing the controller SRX003
I don't see how they are powered? Can you tell me? Thanks!
Based on my understanding, I'm looking at $21 per crossover.
CNR378 https://www.tamvalleydepot.com/support/crossovers.html
IDRick CNR378 https://www.tamvalleydepot.com/support/crossovers.html Thanks for the link. How are the servos powered?
8-24V DC
CNR378 IDRick CNR378 https://www.tamvalleydepot.com/support/crossovers.html Thanks for the link. How are the servos powered? 8-24V DC
IDRick I want an easy functional crossover that is pretty much plug and play plus at a lower cost than a tortoise setup.
Easy, plug and play, and low cost doesn't really happen.
I don't think you should apologize. The Electrical Cognescenti know how to build this with $10 of parts from Ebay. You just need to get one of them to spell it out. I'll be standing by ready to take notes.
edit for spelin
Henry
COB Potomac & Northern
Shenandoah Valley
gmpullman Just the two servos as far as I can see. https://www.tamvalleydepot.com/products/servosaccessories.html Plus a double pole double throw toggle switch to act as a reversing switch to provide reversing DC power to drive the servos. Maybe their DY-5001 DPDT relay would make wiring the servos easier? If you are powering the frog you would get the servo model with the add-on snap-switch. Good Luck, Ed
NO NO NO
Servos don't change direction based on polarity like a Tortoise. Nor do they like to be stalled like a Tortoise. Understandable to get this wrong, since MR published an article a couple of years ago saying to do exactly this, although it required modification of the servos. But they get very hot if stalled, and I can;t imagine them lasting long used as a stall motor, they aren't meant for that.
Most of the Tam Valley controllers will drive 2 servos - so a Singlet plus a second servo would work for a crossover. If there are more than one crossover to control, the Octopus may be the controller, it can control up to 8 servos, serveral can be doubled up but not all 8, for crossovers.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rrinkerServos don't change direction based on polarity like a Tortoise.
Didn't intend to steer the OP wrong. He was asking for non-DCC control and that's where I thought the DY-5001 would drive the servos.
I stand corrected Ed
Thanks, this has been somewhat helpful (remember I'm a total newbie on this topic). My whole thought process on this was simple. I had read a post of Randy's where he talked about using Tam Valley components to control a turnout. Randy has helped me times and never steered me wrong so I thought, I ought to give this a try. I did some reading on the Tam Valley Depot website which gives some general direction but would benefit (IMO) with a practical example showing all the components needed for a simple single crossover and how everything goes together. They could convert me to a "true believer" but I need to have a practical example from A to Z for the simple before moving on the complex (controlling multiple crossovers, yard ladders, etc). Mel has given a good start. I prefer to start with Tam Valley based on Randy's recommendation that it is an easy system for beginners and essentially plug and play. $20 to $25 for the first crossover would not be cheap but would be awesome as a learning experience. Right now on my existing layout I use two caboose hobbies ground throws at each crossover and want to change!
Still cheaper than Tortoises - unless you rig a rather complex mechanical arrangement to use just one, but then you could do the same with a servo and save money there tooo.
The quieter modules aren;t strictly necessary - if you set up the travel when programming the Tam Valley controller, the servo shouldn't be stalled. Plus some of the newer versioons they have already have that built in to the controller. I used the older Singlets, the ones where the fascia controller was the whole circuit, and none of my servos buzzed after lining a turnout.
My DIY Arduino based servo drivers for my new layout will have the same auto shutoff at end of travel so they don't buzz even if not totally aligned, as long as the servo get reach the programmed end position, power will then be cut off. Technically the signal gets cut off, but with no signal telling the servo to move to a certain position, it won't fight back against being moved slightly by the force of the piano wire.
rrinker My DIY Arduino based servo drivers for my new layout will have the same auto shutoff at end of travel so they don't buzz even if not totally aligned, as long as the servo get reach the programmed end position, power will then be cut off. Technically the signal gets cut off, but with no signal telling the servo to move to a certain position, it won't fight back against being moved slightly by the force of the piano wire. --Randy
I did, a while back. It's now completely wrong, as I discovered trying to lay out a PCB for it, it was easier to change which pins I used for what input or output than trying to route lines around one another, so the curent code no longer matched the pin assignment.
But really all it's doing is servo.detach() after the servo reaches end of travel. I have a constant for minimum position and one for maximum position, the the move routing keeps moving the servo until the current position is at or less than the minimum or greater than or equal to the maximum.
Mel,
What do you use to power your arduino controller? Which arduino controller are you using? What mounts do you use to attach your servos to the layout? What is the process to control two servos on a crossover?
I've been looking at alternatives with Tam Valley Depot and they pretty expensive. If I used an OctIII to control 8 servos, it would cost $31 for the OctIII, $80 for the servos + mounts, and $40 for the fascia controllers. Plus another few bucks for servo extensions. Seems to be too expensive for me. I'd like to look at alternatives.
Thanks,
Rick
Yeah, that's the one thing Tam Valley is high on - the servos themselves. They are insanely cheap on eBay. You can buy just the mounts for under $5 each from Tam Valley, or just can just glue the servo on its side under the layout - you don;t really need the fancy mounts.
It's still cheaper than Tortoises. The Octo comes out to less than $4 per turnout, the servo and mount at Tam Valley's price is $9 each, so you're at $13 per turnout. A Tortoise is at least $15 in 6 packs. You still have to add the toggle switch and LEDs to get anything like the equivalent of the fascia controller - though the Octo can use a simple toggle as well, you don't need the fancy fascia controllers. If you get the servos on eBay for about $150 each, the mounts are $6 each, so $7.50 for a servo and mount, plus $4, $11.50 per turnout. Much better than $15+ per.
And for DIY, Geoff Bunza has step by step instructions for setting up an Arduino - you don;t need to know anything about it, his instructions tell you how to load the software and use his existing program on it to then connect servos with buttons or toggles. You can get a suitable Arduino for under $10, I think Geoff's design that uses buttons drives 6 servos. So $10 for an Arduino, $9 for 6 servos, $36 for 6 mounts. Little over $9 per turnout! And there are cheaper mounts than the ones Tam Valley sells. Iow Scaled Engineering has ones that are $15 for a 6 pack of mounts. That works out to under $6 per turnout for 6 of them.
Thanks Mel, very nice and thorough discussion! Gave me lots to investigate on ebay!
Thanks Randy, you're always very helpful and thorough in your commentary! Both you have given great suggestions! This is why I come to the forums!
Best,
Couple quick questions:
Can the arduino drive two servos from one connection point to the controller with a y-servo extender? Tam Valley uses this approach:
http://www.tamvalleydepot.com/support/crossovers.html
Does this increase the number of servos that can be controlled? Say I buy a Uno and have five turnouts plus a crossover. As I understand it, a Uno can control six servos but may be able to control seven if the y-servo connector can be used. I will obviously be a lone operator so will only be switching one or two turnouts at a time.
The tam valley fascia controls + mounts are kinda expensive but I like the easy installation and protection from inadvertant switching. Can they be used with an arduino controller and correctly light showing switch orientation?
For this benchtop test with a very basic switching layout, I'll probably just purchase servo extender cables from ebay as they are inexpensive and free shipping. I agree with Mel I could save money by making my own but for this test premade are perhaps a better use of my time.
The Iowa Scale Engineering mounts are very reasonably priced and have some mounting flexibility if adjustments are needed. Hat tip to Randy!
Lots of good stuff about arduinos on youtube. Randy, thanks for the tip on Geoff B., he's an excellent resource.
And that's perfectly OK at least for controlling turnouts as 180 degree rotation is generally not needed.
As far as driving multiples - here's the trick. A servo has 3 wires going to it, one is ground, one is power, and the third one is the signal line that controls the position based on the width of the pulses that coem over this control line. The 'power' used to turn the motor in the servo comes over the two other wires in the cable. Arduinos have a limit to how much current can be drawn from any one pin before the chip is damaged, however the signal line to the servo draws very little power. So you can connect the signal line of multiple servos to a single Ardunio output without harming anything.
Most if not all of the Tam Valley controllers us PIC microcontrollers, but at the interface level (ie, where you plug things in), that makes no real difference. Hooking multiple control lines to one output is exactly what you are doing when you hook 2 servos together with a wye cable.
No microcontroller can source enough current to actually turn the motor of the servo, those lines connect directly to the power input or the voltage regulator for the entire controller circuit. So while a moving servo might draw halg an amp or more depending ont he load, it's only putting a very minuscule load on the controller to get the position signal on the control line.
Randy, excellent information! Can you give me a recommendation on power supply for the UNO and Mega? Can a wall wart with 1 to 2 amp output (9 volts) be used?
Thanks for clarifying on joining two servos! What about the fascia mounts and lights, how are they connected to an arduino and will show correct turnout location?
Mel, nice set up! Very obvious that you love electronics and are very talented in using it in our hobby! I'm at the barely crawling stage of understanding so be very basic in my test setup. Thanks for sharing!
The regulator built in to the Arduino isn't really capable of driving more than 1 or maybe 2 servos. A 1 or 2 amp 5V power supply (the little bricks used for phone or tablets are a good option - you just have to cut the phone end connector off to expose the wire). For driving 6 or more servos, you'll want a more powerful power supply.
Mel, very thorough description of your power supply set up! Didn't fully appreciate the need for that size at first, now I understand your need for switching power supply plus DC/DC reducing transformers.
For me, I think the best bet is to start small. For my test switching layout, I will use caboose hobby ground throws on single turnouts. For the one or two crossovers, I would use an Uno, 2 or 4 servos, 1 or 2 wye cords, Tam Valley fascia mounts + LED, and a 2 amp 5 volt power supply. Only one crossover would be used at a time so should be sufficient power.
The costs for a higher amperage switching power supply and a DC/DC reducing transformer really need to be included when comparing arduino versus tortoise control of turnouts. Plus, one needs to properly size power supply and transformer to meet future needs rather than planning an initial test setup.
My main use for considering arduino is to operate crossovers. I prefer to use caboose hobbies ground throws for industry, yard track, and single turnouts. Looks like optimizing use crossovers is a great idea to minimize cost, just like for the railroads! It's too early for me to make those decisions. Thanks for your help Mel and Randy!