Good evening. I have a question about servos and controlling them for turnouts. I have been using tortoises for over 25+ years and have no problem with them except the cost, which I can overcome but, I have been looking into servos to use on my second deck due to space constraints and their considerably smaller in size.
What is the best way to control them without diving into all the arduino stuff, which I know zero about. I do not plan to use them via the dcc bus nor am I going to control them with jmri. I have a stand alobe dc power source that I can wire in a voltafe regulator to drop the 12v to 5-6v for the servos. I just want to control them with a pushbutton or toggle on the control panel and have them show indication of position with led's.
Is there a control board that does all this or am I going to need multiple different pcs of hardware? Ive seen the Tam Valley octopus iii but havent researched a lot about it, I know I would need several of them is about all Ive gathered.
Any help would be great.
Thanks
Or I could just keep running tortoises
doubt this answers your query
as an EE, i wonder if multiple servos could simply be driven to either end point using a SPDT switch to select on of two signals: one that is a 1ms pulse and the other that is a 2ms pulse generated by something like a 556 timer.
and underpower (~4V) the servos so that they don't overheat/damage by trying to hold their positions over long periods of time.
if that is a concern, maybe use a momentary center off SPDT and disconnect either signal when done
greg - Philadelphia & Reading / Reading
Jeff,
I'm guessing the tortoises would be easier to install.....The TAM valley site lists other drivers besides arduino and the octopus III. I use switchmasters but several of my buddies use servos and they drive them with arduinos, so no help there...
Good luck with the project,
Guy
see stuff at: the Willoughby Line Site
Instead of servos, I use these little N20 gear motors, they're way better IMO:
Super easy to install. I simply make an arm out of a paper clip or a sewing pin or whatever, attach it to the axle by bending it and gluing it on, and then stick it under the turnout like so:
Powering it is way easier than a servo. With this guy, all I do is give it around 120mA of current, and it has enough force to switch the turnout but not enough to bend or damage anything when it finishes the switch and stalls. No need to fuss with calibrating positions.
All you'd need to power a turnout is one of these motors, two resistors, and two pushbuttons. Under $3 per turnout.
Eg, say you're using a 5V power source. Attach both motor terminals to 5V via a 36ohm 1watt resistor each. Then attach both motor terminals to ground via a pushbutton. The result is that at rest both terminals are pulled up to 5V and the motor is unpowered. When you push one of the buttons, that motor terminal is grounded, but the other is still pulled up to 5V; so current flows in one direction through the motor. Push the other button instead, current flows the other way.
There's no need to mess around with control boards, Arduinos, or complex circuitry of any kind... if you're comfortable with buttons and resistors and LEDs, you're good to go.
I get mine from ebay, searching for "N20 metal gear motor", selecting ones rated under 100rpm. They're about $2 apiece on ebay or I've seen them for around $10 in local electronics stores
I know there are guys out there using servos and I trhink there have been some articles the press. I don't have any specific info.
When I built a double deck layout years ago I used a lot of the remote Tortoise kits - more work and money - but they work fine.
No more double decks for me, and my control sytem is designed around the Tortoise, which I have plenty of, so I never got too deep when I saw the info on the servos. I have never been one to mix and match different equipment on the layout.
But I think for a double deck where space matters it could be a real good idea.
Sheldon
alternatives to tortoise machines should consider
santafejeff . ... and have them show indication of position with led's. ...
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... and have them show indication of position with led's. ...
Most servos I've seen will not do this.
SantafeJeff,
Take a look at Berrett Hill touch toggles. He has a nifty system for setting up control panels to operate turnouts with servos. Very easy to change the panels if you alter tracks on your layout. No programming required. Reasonably easy to assemble/install the setup. Arduino systems are very cool but one must be a tinkerer. You will be learning programming and lots of electronics. Very doable if that is your inclination and you have the willingness to go through multiple learning curves.
Personally, I would recommend commercial systems such as Berrett Hill or Tam Valley if one is a newbie with servos over designing your own Arduino system. Both are price competitive price-wise with the Tortoise.
Not affiliated with either commercial firm. Have played with small arduino setup and quickly decided I would go with a commercial servo system or go with a different turnout control. With the current economy, I went with Caboose hobby ground throws on my switching layout.
If you really want to keep cost down, many people use a servo tester to control their turnouts. They can be purchased for less than $3 in quantity. I've seen them used simply by turning the knob on them or replacing the pot with a resitor and toggle. They can be mounted with a piece of aluminum u-channel from the hardware store.
Youtube has a number of videos on turnout control with servos. It might help in your decision.