Video Transmitter on FailSafe

[workshop]

I’ve had my video transmitter on a switch for an “emergency off” situation should one arise. With almost 10 hours of accumulated flight time, I have yet to have a control glitch, much less one attributable to the video transmitter.

I’d like to free up the channel and save the weight of the electronic switch by elimination it as the video is always on anyway. However, I’d like to run the decision by the group to get a design review, second opinion and point of reference.

Do you fly with video transmitter on an “off switch” for emergency failsafe? If so, at what power level (mW TX output).

Thanks Jeff

BTW – The R/C-Autopilot System is completely isolated electrically (separate power systems and grounds) and from RFI (shielded enclosure) from the Video System. The RX and TX antennas were carefully placed to avoid crossover.

[kd7ost]

Hey Jeff,

That’s cool you can turn it off and on in flight but I ran into the same thing and needed a channel freed up. I considered having it come on and off with an altitude lock or other enable circuit but finally opted to just keep it powered on at all times. I was pretty reliant on the Video, but not the autonomous systems.

That is the one device I have an external switch to though. After I get my engine warmed up and am ready to go, I turn it on just before my take off run. I'm sure your system is like mine in that the A/V system takes more power than everything else combined. (Minus an electric motor of course)

I power my A/V which includes, camera, mic, and 600mw BWAV 2.4 Ghz transmitter from a 3 cell Lipo pack and a switching regulator. I have no troubles with that setup and have been running it that way for several years now. I stand by it for short term, 2 hour or so, flight times when using an 1100 mah Lipo or LiIon pack.

Dan

[workshop]

ooooh... That's good battery data. My 4-cell 2000mAh lipoly is cooking the 12V linear regulator. I’m going to save an ounce and switch to a TP2100 3s battery (same as on my receiver and son’s airplanes) because my 20-minute flights barely use any juice.

I have the same procedure; we test manual flight control, GPS acquisition, throttle and finally Autopilot on/off before we power on the video system (check transmit, check record, check OSD, reset altimeter and clear the strip!). :D

I haven’t attempted “fly by camera” or RPV or whatever they call it as that’s outside the scope of our project. I have, however, made PicoPilot course and altitude adjustment once under autopilot using the override feature. We have to improve our “vision” before we attempt manual RPV. :rolleyes:

Jeff

[kd7ost]

Very cool Jeff.

I use the 5 vdc switching regulator from Dimension Engineering for the transmitter. My Camera and mic get the straight 3 cell lipo and the transmitter gets the 5 volts. Real clean power and very efficient. The guys at DE are great and have lots of cool stuff at great prices.

Dan

[Terry S]

I have had problems with a 500mW TX but none using 100mW or less. I use a separate 3 LiPo to power the setup but no off switch. I would be more worried if the video was lost than a glitch or two.

Terry

[JettPilot]

IF your failsafe is setup properly, you do not need any video switch. I have flown my plane to the very limits of its range, and gone into failsafe over 100 times on some flights according to the flight recorder. Its no big deal, as soon as it goes into failsafe, the plane turns towards me and the signal is regained very quickly.

When the plane goes into failsafe, I know I will always get control back as the airplane changes orientation, it does not even bother me. What I do not like is losing video, as long as I have video I can do whatever it takes to fly the plane. I would never design a switch in to trun off the video. The video output power is 5 watts, and no special shielding or isolation is required for the radio gear.. The best method is to put as much distance between the TX and the planes RX as possible.

If you try to be "overly safe", you end up making bad choices and create more problems than you started out with.

JettPilot

[workshop]

I don't have any practice flying by video. I guess I should give it a try if for no other reason than to practice recovery. My friend Ross and I are planning some over the ocean flights (he'll wait with a chase boat at a predetermined waypoint with a secondary vid/data receiver).

So the "emergency video off" e-switch is gone! Thanks for the help guys! :)

And thanks for the wallpaper Rosa! ;)

Jeff Parisse
www.teslacoil.com

[typicalaimster]

I use a 2100mah 3 cell pack to power my camera. Between the LiPo and the voltage regulator I installed a manual switch. This will allow me to turn the camera off when I don't need it. One AMA club in my area has personally asked me not to use the FPV part of my setup when I'm at their field. Usually I'll unplug the power to my video system when I fly at that field..

I've used the same pack to power all my equipment on a different plane but draw from a different voltage regulator. I've gone as low as a 2 cell 1300 LiPo pack for video power only. I have not ran into a issue where the video TX was the root cause. Most of my problems were power related.. That whole oh I can squeeze a bit more out of this regulator, or I have enough power for another go around.

Fly by video takes a couple of goes to get used to it. It's a very good tool when you go out of visual range. You already have the flight stabilization so you should be fine there. Most people, myself included, make the mistake of not familiarizing themselves with the area before they fly. Study any aerial map you have of the area. Having video from the day before is also a great resource. Having GPS telemetry coming down is a big help. It's nice to have a moving map display up so you know when to make your turns. It sounds like you already have a production plane. I'd suggest trying FPV on a plane you don't care about first. When you try landing via FPV you might find yourself coming in either to hot or to slow until you get used to it.

[JettPilot]

One AMA club in my area has personally asked me not to use the FPV part of my setup when I'm at their field. Usually I'll unplug the power to my video system when I fly at that field..



That sucks ! I hope it isnt NVRC... While flying at clubs, I have had many close calls due to incompetent pilots that can barely control thier airplanes, and have even had to jump behind the bushes :mad: Your FPV flying has never even come close to worrying me...

JettPilot

[NorfolkSouthern]

I have a Nexstar with an AFS system that's switched off. I would like to install a fail-safe if possible, just in case it goes out of range or there is interference on the signal. And yes, I always make sure the RX battery is fully charged and the plane is fully inspected before flight. How would I install a failsafe with auto-return on my plane? How much would it cost? Any information would be of help. If the clubs don't like the safety feature, that's fine and I can always think of some other place to fly. I'd rather have that then either lose a $300.00 plane or end up with it being returned with a hefty bill for a paint job on somebody's car.

NorfolkSouthern

[dzbum]

Norfolk,
there are several different ways of achieving what you want to do all of them with different costs.
There is an "off the shelf" product that is produced by Unav.
http://www.u-nav.com/picopilot-RTL.htm

There are basically 4 components to what you want to do.
1:A failsafe device that will return controls to a neutral position and turn on the return to home system.
2:A GPS receiver that is capable of plotting a course to a predetermined point. (You)
3: An interface device that interprets the GPS directions and converts them into servo movements.
4: A mechanism to level the aircraft and/or hold its altitude.

Item 1 is taken care with a PCM receiver that allows you to preset the servos and will send an output to engage a return to home system. There are PPM receivers available now that do also have failsafe as well as stand alone failsafe devices. FMA make such a receiver which I will talk about with Item 4.

Item 2 can be done with a small handheld GPS such as the Garmin Geko or similar.

Item 3, now this is where it starts to turn it to more of a religious not a technical discussion ( Just kidding ) everyone has a favorite device and a good reason why. I would suggest something like a RCAP2 http://scalerobotics.com/store/catalog/product_info.php?products_id=31&osCsid=5cd399c3d7aba79aaba32650d9366011 but there are others.

Item 4, this can be done with either natural stability of the aircraft in combination with your failsafe settings, or using a stabilization device such as FMA's Co Pilot. This is made as an add on unit or as part of a receiver with failsafe. http://www.fmadirect.com/products.htm?cat=29&nid=7 This uses Infrared sensors on both axis of the aircraft to sense the horizon and keep the aircraft level.

Hope this helps.

Dzbum

[NorfolkSouthern]

That does look helpful, thanks for the info Dzbum. The AFS on my Nexstar uses light sensors, not infrared. It's good for use when the sun is high up in the sky, but can't be used when the sun is low to the horizon, over water, or over snow. I may need to replace that unless I want to limit my experiments to certain times of the day.

NorfolkSouthern