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#1 rangamatchstic Feb 01, 2012 04:49 AM

school project
 
My goal is to make a plane retreivial system that turns on when the receiver loses power or signal and it uses gyros to level out an rc plane then turn it 180 degrees in a gentle slow turning bank aswell as turn, then it has to fly level after the turn, fly for about a quarter of the total time you have been flying for then slow down until it stall s and deploy a parachute. My only problem im going to have (i have looked into all the other components and found ways to do them using components available to me) is i want a single signal wire to be attached to the servo signal wire at all times to control the servos when the planes receiver loses signal. What i am wondering about is A. will the receiver lock the servos in place if it losses signal and can you change this setting if so, and B will the receiver be ok when a signal is given to the servo on the same wire ie will this short the receiver out. :popcorn::popcorn::popcorn:

#2 srnet Feb 01, 2012 05:05 AM

Quote:

Originally Posted by rangamatchstic (Post 20603115)
A. will the receiver lock the servos in place if it losses signal and can you change this setting

Depends on the actual receiver, there are several different behaviours here.

Quote:

Originally Posted by rangamatchstic (Post 20603115)
B will the receiver be ok when a signal is given to the servo on the same wire ie will this short the receiver out.

You cant directly connect two outputs together, which is what you are suggesting. Extra components are needed to, in effect, turn off the receiver output.

#3 srnet Feb 01, 2012 05:09 AM

Quote:

Originally Posted by rangamatchstic (Post 20603115)
in a gentle slow turning bank aswell as turn

Its the wings that make the plane turn so the plane will have to bank over.

#4 rangamatchstic Feb 01, 2012 05:43 AM

Quote:

Originally Posted by srnet (Post 20603176)
Depends on the actual receiver, there are several different behaviours here.

The receiver i will be using is a turnigy 9x



You cant directly connect two outputs together, which is what you are suggesting. Extra components are needed to, in effect, turn off the receiver output.

im not connecting the power will only be provided to the servos by the circuit if the receiver losses power and i am thinking that the receiver will already have a diode to prevent damage if you plug a battery in the wrong way around.

#5 Circlip Feb 01, 2012 05:49 AM

Used to be an electronic black box in the UK about the 70's that on loss of signal centralised the servos and cut the throttle to half. A later system deployed a parachute to float it down.

Possibly Roy Lever, I think he made and sold the system commercially, - nothing new under the sun.

Regards Ian.

#6 rangamatchstic Feb 01, 2012 05:58 AM

meh, still want to have a go at it.

Also what component could i use on the two outputs? i was thinking of a diode but that drops the voltage by 0.6v and the analogue servos work on a voltage reading =/.

Also i know plane have to bank to turn, i used to fly and rc nitro plane and park flyers but now fly helis and drive cars.

#7 Andy W Feb 01, 2012 06:06 AM

Suggest you also browse this forum:
http://www.rcgroups.com/uav-unmanned...-vehicles-238/
..a

#8 rangamatchstic Feb 01, 2012 06:24 AM

stuff it just work it out myself i guess =P

#9 rangamatchstic Feb 01, 2012 06:27 AM

ill just use a lot of mechanical switches activated by a servo on the fail safe that will turn change the control to the seperate circuit board, probably activated by the same circuit ill use to get the seperate circuit board going

#10 slipstick Feb 01, 2012 07:31 AM

Quote:

Originally Posted by rangamatchstic (Post 20603400)
Also what component could i use on the two outputs? i was thinking of a diode but that drops the voltage by 0.6v and the analogue servos work on a voltage reading =/.

If you think analogue servos are controlled by varying voltages this is going to take you A LOT of working out. Hint - the servo control is a varying pulse time NOT a voltage level.

Steve

#11 eflightray Feb 01, 2012 09:50 AM

Perhaps a silly question, but the '......it uses gyros to level out an rc plane then turn it 180 degrees in a gentle slow turning bank aswell as turn,.....'

What if it isn't flying directly away from the pilot when the system takes over ?

#12 srnet Feb 01, 2012 11:56 AM

Indeed.

And why let it glide for a 1/4 of the flight time ?

If you flying fairly close in, then the plane is more likley to be further away when the parachute is deployed.

I would think that even limited return home functionality would require a GPS ........

#13 jeffs555 Feb 01, 2012 03:23 PM

OK for an academic exercise, but why a parachute? If you lose radio contact, it is most likely because you flew out of range. If you flew out of range then a simple 180 would most likely get you back in range.

Also, if your receiver batterys fail, the servos would not function. If using a separate battery for the servos, that is the one most likely to fail since the servo's have high current drain compared to the receiver which has very little current drain.

#14 Kiku0 Feb 01, 2012 03:35 PM

How about a compass and gyros on 2 axis (one to bank, other to keep the pitch). When the signal is lost for x seconds it starts to turn until the heading is 180 degrees different. If the signal isn't restored in y seconds after the first turn, it will do an full circle, the process will be repeated till the signal is restored. If you put it on a slow turn and the plane is in visual range, you will ultimately get the plane back, even if it involves some running towards the plane

#15 srnet Feb 01, 2012 03:41 PM

Quote:

Originally Posted by jeffs555 (Post 20608490)
If you lose radio contact, it is most likely because you flew out of range. If you flew out of range then a simple 180 would most likely get you back in range

I guess it possible, with poor RC gear, but then why use poor RC gear in the first place.

The only crashes that I have experienced, apart from those induced by the idiot behind the sticks, were power or mechanical failures. Loose wires, switches, plugs and the like plus a couple of Lipo failures.

Going out of range, nope, I have difficulty flying a model when its half a mile away anyway.


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