I am new to this and would like to know the nature of the three wires. I presume that I have a center one with the pulses coming thru between either negative and positive from center. If I have a limit switch on my turret can I then open up the circuit say the negative until the turret is moved away again from the limit switch. This would provide me with a sensible solution not to overshoot the limit thus set. hope I was able t explain myself and look forward for an answer
Okay a few guidelines: For a Futaba, the black is ground. The red wire is positive, and the white wire is signal. For Hextronic, brown is ground, red power, and orange signal. I don't hve any other brand's servos inside the house to get colors from, sorry As far as cutting the ground wire with a limit switch, NONONONONONO. All that will do is kill the servo when it rotates too far, and it won't come back until you (by hand) rotate the servo so the limit switch closes again. Without an intact positive and negative, there is no power for the servo to rotate, including rotating away from the limit switch. The signal that tells the servo where to rotate to is the signal wire; the positive and negative are only there for power supply and have nothing to do with how much it rotates. Your radio transmitter should have a means of setting how much travel the servos have. An experienced battler near you can help you work it out, some radios are more complicated than others (or like the cheap Chinese one I have, require a connection to a computer). The transmitter is where you want to limit travel.
Hi Fred, if you're thinking about turret rotation, there are several solutions. You could rig up a complex system of wires, switches, and servos that disables rotation in a single direction upon reaching the desired limits. This was used for many years in Big Gun clubs, but I haven't seen any since 2005. They basically limit you to a on-off-reverse control, and are also less water- and damage-resistant than more modern setups. You could also rig up a set of limiters that physically stop the turret at the end of its range of motion, and use a belt that can slip. This method is currently the most popular solution, since it can be used with just about any turret rotation controller. You could also use the standard-sized sail winch servos that Strike Models sells, and use end-point adjust on your radio to set the range of motion. That's what I did with my current battleship, the Viribus Unitis, although I still use physical stops and a slipping rotation belt so I can re-set the turrets if they get bumped around in battle by a wayward torpedo-boat.
Thanks for a speedy reply, guys! My turrets have a gear teeth ring on the outside. They are driven via meshed gearwheel driven by a servo. So I don't have the luxury of slipping clutches via the belt drive. Now the problem is that I need to stopbefore I hit the deck. That is why I need some limit switches. Now I know that I can't do it that way so I will use a dc motor and then I have to devise a switch solution that fits. Whilst I said that I would use a microswitch I intend to use a sensor similar to a reed switch (size about 3mm dia). I will use the a simple picaxe controller which I will pott so that it is waterproof and it is very lighteweight. I know its a fancy way to go about it but I have positive control all the time no resetting etc Please tell me that I am a bit kookoo I can take it, but if anyone has done something similar I would like to know. I also have a diagramm of the sequential functions which controls the rotational "stops" as well as the elevation modes. Thank you for your reply it's the challenge to build the "Ding" so that I can accurately Dong the enemy !!
First of all, Fred, what size servo are you using currently? It sounds like you can simply swap out whatever servo you're currently using with a sail-winch servo (especially the standard-sized one from Strike Models), and use the end-point-adjust feature on your radio to dial in the endpoints for your turret rotation. That is exactly what Gascan and I did with our ships, the only difference being we used a belt-and-pulley linkage between servo and turret, rather than gears. If you do not have end-point-adjust on your radio, you can use the Servo Extender unit from Servo City. The Servo Extender is capable of extending the range of motion of your servos, but it also has end-point-adjusters built in, along with a neutral trim. I have two, that I was planning to use until I found a radio with end-point-adjust for channels 5 and 6. I would caution you about using gears in your turret rotation mechanism. Over the years, I have found that bumps, scrapes, and collisions are a natural part of the battle. Turrets get hit and knocked about. It's actually quite common. I have yet to find the gears that are strong enough to resist the impact of a 45-lb battleship moving at 33 knots. If you stick with gears, it's a good idea to keep a few spares with you, just in case.
That is my problem! I am trying to find a servo that works for me...? First I need to learn how to upload a picture with this message. It would help if somebody can tell me since that would help to explain a lot of things. (Chinese say a picture says 1000 words...!) Thanks fellows
I would love to see a picture of what you've got so far. That would help a lot in understanding what you need. Instructions for uploading and sharing photos can be seen here: http://www.rcnavalcombat.com/Forum/tabid/58/aff/542/aft/406734/afv/topic/Default.aspx For a servo, consider the Strike Models sail winch servo. You can get it here: http://www.strikemodels.com/products/servos/
OK, thanks Kotori87 found the site you gave me it was instructive but not correct but a little imagination goes a long way... Now I have put some pics up on my "page" users/rednib... and Voila even dickheads like me can do it ! Here the rotational area plan. The shaded area is where the the turrets can operate A,B& C are the "Limit switches" A switches are rotational action only B & C will affect both rotational and deflection or elevational movement. This photo should provide you with an idea of the whole size and concept of the rotational movement. The gears are quite sturdy they coming from a drink vending machines auto cup drop station By the way the whole "shebang" is built into a lightweight craddle which is suspended from the top deck structure. Here a closer look up of the three stage geartrain Center gear wheel (the smallest) are both on the same motor axel driving both forward turrets via separate intermediate gear and then onto the turret wheel. To give you a better idea of the size of these wheels There will be no ripping down the Gear wheels or stripping the teeth off!!!! I hope this will give you a better idea of what i am doing ... any comments will be accepted and even if it means that I shall have to revert to the belt driven solution then so be it ...The gearwheels are available from an italian Manufacturer but I believe there is also a US manufacturer somewhere in New York state.??!!! Thanks again for yourn help and input Its much appreciated , Fred Binder
Wow, those are some pretty impressive gears. What pitch are they? Servo City has a number of gears designed to fit on servo splines, in both 48 pitch and 32 pitch, for both Hitec and Futaba servo splines. If you can use that, the Strike Models sail winch servo would work great. If they aren't compatible, it still may be possible to mount one of those gears onto a circular servo arm.
Ok Kotori87 I think you misunderstand ...Sorry I might not have expressed myself properly. As you can see from the photos I can either mount a Servo (3wire) or I can mount a 6VDC motor (powerfull & sealable) On the second photo you see the servo behind the dc motor. Now how do I stop the motors from hitting the superstructure and on the front side not hitting the deck or the cannon when I move the two turrets from starboard to port side.???!!! Unless I can get two segments into programmed into the transmitter...???!! (see also the previous photo, operational area)No doubt you realize that the gearwheels will stall the motors before they strip the gears! and if I get a bit too close in battle I just swipe their belt driven guns out of the way...!!! At the same time I have uploaded some photos of my proportianally integrated ruddergearbox (for two rudders!) That turns the ship around at a faster speed since the forward movement is maintained if not improved. It obviously works best at full speed !!!! Tried that out and it makes a hell of a diff! It's a bit like the wheel geometry on a car..??!! Finally there is also a picture of the Powerplant. I am using two powerfull 6VDC motors each driving via a splitter gearbox two props. Maybe you can see that the gearwheels are "angle toothed" i.e the teeth are at a 30 deg angle. I can asure you with these babies you can go at full speed from full forward to full reverse there is no meshing problems! Again tested and works absolutely positively perfect. OK hereunder the pics, please keep the questions coming thanks Mate, Fred view from the underside with a DC motor fitted I have made a shaft that fits onto the motor and the two first drive gears (the smallest ones) are fixed to this shaft Ignor the blue lexan, its from the front of a Pepsi Vending machine! Here I am trying to show that I can fit a servo or a dc motor one or the other...! Here my "piece de resistance" a Proportianally Integrated Steering Rudder (box) also known as a ..... pisser you can see the rudder position on full angle. This can of course be adjusted to suit !! Again I can drive this baby with a servo or a 6VDC Motor Note again lots of parts from a vending machine! Here my propulsion unit with two powerplants feeding via a splitterbox to each of two props
Let me see if I'm understanding this. You currently have a DC electric motor driving your rotation system. When the turrets hit their physical limit, the motor stalls out, stopping the turrets but draining power and stressing the parts. You want to build an electrical limiter system, so that the turrets stop short of their physical limit, right?
Absolutely correct ! What I would like to know is how to connect a dc motor to the rx for example how do you drive/ control the propulsion motor which is usually a dc motor Thanks for staying with me
You will need something like a pair of Team Delta cards, or one of the 'twin firing cards' being put out by JADFER on this site, to interface your receiver with the electric motor.
sorry tug boat but where do I get info on the Team delta cards or Jadfer on this site..?? Thank you for yr help
Ah, ok. Now I think I got it. You need some way to control the motor from the receiver. From what you've said, it sounds like you tried to plug the motor directly into the receiver. Is that about right? If so, what you need is an ESC. edit: ok, whoa, took too long. Anyway, there are a number of ESC options out there, the Team Delta boards are not the only ones. Mtroniks Viper Marine ESCs are highly recommended. I have used them for over 6 years with much success. Another option to consider, if your turret rotation works on 5v to 7.2v and 1amp current or less, is to use a VEX motor controller board. You can get them here: http://www.vexrobotics.com/products/accessories/control/276-2193.html A number of people in the WWCC use these. You need to replace the three-plug connector that's already there with a standard servo connector, but it works great. It runs the motor on whatever voltage your receiver is getting, or you can wire up a circuit to power it from a separate battery (up to 7.2v pack) if you need more voltage. The best part is that it is very compact, very light, and very easy to waterproof. Pot it in epoxy, or paint it with Skotchkote, or even slather it with a thick layer of rubberized superglue.
You also appear to have room to mount a pulley on the connecting gear to go with a sail-winch and belt. Or, leave the turrets geared together, and belt drive one (the other will follow). cheers,
