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Main => Builders Discussions => Topic started by: pcpilotmd80 on March 19, 2015, 04:36:43 AM

Title: Servo survey?..and gauges
Post by: pcpilotmd80 on March 19, 2015, 04:36:43 AM
Hey all!

Looking for advice on what's been the best/reliable servo out there? (Ones to avoid??) I'm gonna need a lot of them for my DC-9 project, and most of them need to spin 360. I couldn't  find anything in the topics here at CB just throwing one out there now.  I know a lot of manufactures cater to the 737 with gauges, could use those and just swap out face plate with a decal and still work?? ..or are those only specific to 737 software platforms? Any help is great!

Thanks,  Mike
Title: Re: Servo survey?..and gauges
Post by: 727737Nut on March 19, 2015, 04:48:55 AM
Allot of your gauges can be driven by PWM alone as they are just good ol meter movement coils. AKA oil temp , press, EGT,etc   The others, use a 2 to 1 gearing on the back with a micro servo and you'll be good to go.  The servo is only as good as the controller and software controlling it.  You want absolute smoothness, BIG bucks for all digital servo's and a 12bit resolution controller.  You want average resolution and not as smooth movement then you are in luck. FYI to all, i have watched literally 100's of vids of real cockpits and none of the gauges operate smoothly in real life.  I have had good luck with 7-10 dollar micro servo's and arduino, opencockpits, and Pokeys with FSSymphony. The really cheap 2-5 dollar servos tend to burn out easily.   

Rob
Title: Re: Servo survey?..and gauges
Post by: Trevor Hale on March 19, 2015, 05:18:50 AM
I don't use 360 degree servos, I use 180 degree deals.

I have bought these in the past and they are junk (I had a 33% Working ratio on the ones I purchased)  I bought 3 and 2 failed.  One the gears were stripped to begin with, and the other had the wires fall off, and they were unsolderable back together as the board they attached to was destroyed by heating on the initial solder job.
(https://www.cockpitbuilders.com/proxy.php?request=http%3A%2F%2Fcdn.coxengines.ca%2Fimages%2FP%2FCox%2520010%2520020%2520049%2520Micro%2520Servo%2520Futaba%2520Hitec%2520JR%2520Airtronics%25201.jpg&hash=309622b182b2f934bed705565001056359e59107)

Now, I was using these and I really love them, they are not micro servos, but they work well.
(https://img.fasttechcdn.com/117/1170301/1170301-4.jpg)

All I drive with the Arduino UNO and 9685 12-bit PWM card.

You can also always count on Futaba S3003 Servos..

Trev
Title: Re: Servo survey?..and gauges
Post by: pcpilotmd80 on March 19, 2015, 06:33:48 AM
Awesome info, thanks!

Sorry for rookie-ness but what is a "PWM"? And any suggestions good place to purchace?
Mike
Title: Re: Servo survey?..and gauges
Post by: KyleH on March 19, 2015, 07:17:08 AM
PWM = Pulse Width Modulation
Instead of a steady voltage, It is pulsed at a specified frequency. The width of those pulses are then varied to control what ever it is your driving.
The result is that you essentially get an equivalent voltage to the % of the pulse width applied.
i.e. Input voltage = 5V, Pulse width = 60%, resulting average output is 3V.

You can get servos at an RC hobby store.
Title: Re: Servo survey?..and gauges
Post by: Joe Lavery on March 19, 2015, 05:54:32 PM
You can also use Pulse Width Modulation to vary the intensity of LEDs, something you will find in Arduino and other Microprocessor coding. This is how dimmers some work as well.