ADI follow up and Help needed

[Guest]

Hi,Finally I have dispose the original motors and wiring. Now I am in front of a new dilema. The heads of the motors are in fact gears. If I do remove them, I really do not see How I could place the RC servos, or then I would need custom CNC machined pieces. Big Deal.For the X axis it could be possible, but not for the Y axis, becausein that case the servos should also act as main axis. This seems to me like making a swiss watch.Now as you can see on the pictures there is just enough place for a stepper motor but not for a servo, even a small one. Advises are needed and welcomed.RegardsRoger

[tigert 0]

>Hi, >>Finally I have dispose the original motors and wiring. Now I >am in front of a new dilema. The heads of the motors are in >fact gears. If I do remove them, I really do not see How I >could place the RC servos, or then I would need custom CNC >machined pieces. Big Deal. >For the X axis it could be possible, but not for the Y axis, >because >in that case the servos should also act as main axis. This >seems to me like making a swiss watch. >Now as you can see on the pictures there is just enough >place for a stepper motor but not for a servo, even a small >one. >Advises are needed and welcomed. Hi Roger!Ask dirk how far he is with the stepper motor controller for fsbus? That would perhaps work..?Or could you use the shafts of the original steppers and somehow attach the servos to those? Could give a bit more space to play with?Tuomas

[Guest]

>Or could you use the shafts of the original steppers and >somehow attach the servos to those? Could give a bit more >space to play with? Tuomas,Thanks for your reply. I am of course full of hope about Dirk's Stepper controller. The problem has two solutions:1. I let make some CNC machined pieces based upon the one inside the ADI and adapt it in order it fits for RC Servos.It is the most expensive solution, but we can see through.2. I find a Stepper Motor with a 8 teeth shaft which fits perfectly inside the existing gear frame. Cheapest solution, but are the stepper OK for an ADI ??????? and will I find the size and shaft ??????Be with Stepper, or not to be with stepper, that's the question!!!!!And I have (yet) no idea.RegardsRoger

[Guest MikePowell]

Hi Roger,Not an all inclusive list, but at least a few possibilities to start the discussion:1 - Use smaller servos. Tower Hobbies www.towerhobbies.com sells RC servos from several different manufacturers. Some are quite small and may fit.2 - Use small stepping motors. The head positioner motor on some older floppy disk drives is about 3/4 inch in diameter. I believe motor 22M008 from Alltronics www.alltronics.com/stepper_motors.htm is such a motor. This is a 15 degree per step motor and would require you to use the existing gears to get smooth movement of the sphere.3 - Use larger stepping motors by removing everything inside the sphere and fabricating new mounting hardware. Such motors are available that are 1.6 inches square and have very robust bearings that could support the weight of the sphere and become its axis. Choosing a motor with 400 stepping per revolution will provide smooth movement without gearing. Using half stepping will result in 800 steps per rev. Available from Jameco www.jameco.com part #163395 for example, as well as Alltronics and a variety of other surplus electronics dealers.4 - Use a small DC motor. This will require adding some sort of position feedback, like a potentiometer. Motor torque may be an issue depending upon the gear ratio in the ADI. (Alltronics, Jameco, etc., or take the motors out of your RC servos)5 - Reassemble original motor and reverse engineer operation. Helpful synchro info at www.polysci.com/Documents/resynchro.pdf )An issue that should be considered is the rotating electrical connection used to power/control the sphere rotation. The ADI originally used a set of slip rings. The current rating of these is unknown. Use of low voltage, high current motors may dramatically shorten the lifetime.What were your plans for driving the eventual solution and for interfacing to the simulator software? (MSFS or X-Plane?)Mikewww.mikesflightdeck.comInfo for simpit builders.

[Guest]

Hello Mike,Your a real encyclopedia. It's amazing the infos one can get from you.Thanks a lot.I was full of hope as regards X-Plane but must say that even if the software is more fluide, MSFS offers more inputs and outputs possibility and it is why I did choose it.>1 - Use smaller servos.In that case I have to rebuilt the all thing. I would love to be able keeping the existing gear.I must say that my knowledges in that area are very poor. I have some experience with Radio Controls but not that much.What will the next issue if by chance I could get a small stepper inside the sphere ??Kind regardsRoger

[tigert 0]

>>1 - Use smaller servos.>In that case I have to rebuilt the all thing. I would love >to be able keeping the existing gear. >I must say that my knowledges in that area are very poor. I >have some experience with Radio Controls but not that much. >What will the next issue if by chance I could get a small >stepper inside the sphere ?? Microservos are about the size of your thumb tip. Those very likely fit inside the stepper motor "holder", and if you can attach the original stepper motor's gear into the servo shaft, then it can work out.FSBus's servo control module sounds like the obvious choice, no experience about radio control models is needed I guess. The servos just have 3-pin wire with a connector that fits the fsbus module.For artificial horizon servo movement is enough anyway, since it shouldnt roll around, right..?Tuomas

[Guest]

>For artificial horizon servo movement is enough anyway, since it >shouldnt roll around, right..?Tuomas,I do not intend to fly some fighters, but basically a spheric attitude indicator must roll around,in both axises.RegardsRoger

[Guest MikePowell]

Roger, Tuomas,If you can get a small stepping motor in the sphere you will next need to route the motor wires such that they do not interfere with the sphere's rotation. Perhaps the old slip rings can handle this. Then comes the motor control and drive electronics. This can be handled with a PIC16F628, a few transistors, and a few hours coding the PIC. Alternatively, a FerretTronics www.ferrettronics.com product might be used. No personal experience with their products but there have been favorable posts about them. Either approach leaves open the issue of interface to the host computer. "A bit of C code and FSUIPC" should do that. (Ahh, how easily that rolls off my keyboard. (my)Ignorance is bliss.)Tuomas, do you experience with the micro RC servos? If they would fit in Roger's ADI, would they have enough power? If so and if FSBUS can drive them, they would seem a good end-to-end solution.Roger, I thought X-Plane made getting data in and out of it an easy matter utilizing UDP packets.Mikewww.mikesflightdeck.comInfo for simpit builders.

[Guest]

>Roger, I thought X-Plane made getting data in and out of it an easy >matter utilizing UDP packets.Mike,The datas go in and out easely, indeed, but they are limited.At this stage there is no possibility to get multiple throttles, props, mixture working. X-Plane supports in that case only expensive commercial products.The major "do it yourself" circuitry like FS Bus i.e. are also linked on a software basis to FSUIPC. I know that since few days there is a XPLGM.Dll which came out, kind of FSUIPC. But it will need time to get Xplane as customizeable as MSFS is. Last point but not least, Austin went in a wrong direction as regards the scenery format. The sceneries of X-Plane are really old fashionned, and I dont see how he will manage that. I liked very much this software, since it gives more the feeling of an evolution in a fluide. One feels the aerodynamic, and that's not really so with MSFS. RegardsRoger

[tigert 0]

>I do not intend to fly some fighters, but basically a >spheric attitude indicator must roll around,in both axises. D'OH, of course. Silly me. Now that I think of it, of course it is like that..Tuomas

[Guest MikePowell]

Okay, now I understand. I am somewhat disappointed. Soon I will have to write some interface code. I have written some simple code in C++ using sockets and feel a bit more comfortable with the thought of UDP packets than with getting into FSUIPC and MSFS. It would seem that it's better to stick with MSFS.Thank you for the explanation.Mikewww.mikesflightdeck.com

[tigert 0]

>Tuomas, do you experience with the micro RC servos? If they >would fit in Roger's ADI, would they have enough power? If >so and if FSBUS can drive them, they would seem a good >end-to-end solution. They dont have much power, but they have gears though, so they have more torque than the tiny motor would have directly. Could be enough. But like Roger said, they are not really suitable for an ADI. Would work great for other analog gauges though like airspeed, fuel, vario, turn coordinator etc. Just for the "goes several turns" ones you need steppers I guess."Pico"-servos are very small though, attached a pic of one. I think I want to build the FSBUS servo controller board just to play with those, I have some servos around from the RC planes I do anyway, so it's just the PIC and some "glue" to get it assembled.. I guess I could do engine RPM meter or something that is a bit away from the other gauges (that are in the monitor) - it would be a fun experiment anyway, and I bet it looks cool when you see the real physical needle spin..Tuomas

[tigert 0]

>Okay, now I understand. I am somewhat disappointed. Soon I >will have to write some interface code. I have written some >simple code in C++ using sockets and feel a bit more >comfortable with the thought of UDP packets than with >getting into FSUIPC and MSFS. It would seem that it's >better to stick with MSFS. >>Thank you for the explanation. >>Mike >www.mikesflightdeck.com Of course there is FlightGear which is a free software project. Meaning "if you dont like the flight model, write your own" -kind of free, I havent tried it with a decent computer and controls yet, but they say it is pretty impressive.It is in active development, the guys doing it seem very enthusiastic, but naturally it doesnt have all those add-ons and the completeness of scenery that FS2002 has. Interesting project nevertheless. It has real stars for example, so you could navigate the Lindbergh way :-) - also there are lots of scientific research people contributing to it and trying out flight models etc.. a very very interesting project if you are into the coding side of flight simulation. It also does native "wideview" with networked computers etc.www.flightgear.orgTuomas

[Guest MikePowell]

That is quite small, Tuomas. I haven't worked with any that small. I have partially completed prototypes of a Cessna style attitude indicator and a VOR/GS CDI, each based on a pair of "standard" size servos. Each needs a fair amount of work as well as the electronics.Thank you for the pointer to Flight Gear.Mikewww.mikesflightdeck.com

[Guest]

Hi Mike.Could you post some pictures of the attitude indicator & the VOR gauge?Thanks,Jim