Pixhawk Locks Up with Retracts - Always Use BEC to Power Servos

This is the Castle Creations BEC used in the video: amzn.to/1GKLPFB
As with many lessons in this hobby I learned this one the hard way. You want to make sure and use a BEC to power your receiver, which will ultimately power your servos. I had my retracts setup to pull power from the receiver without a BEC and it consistently locked up my Pixhawk. Took me a while to figure this out and I wanted to share this with you to prevent you doing what I did: crashed in the field and another time in the garage.
Please post any questions or comments below and thanks for watching.

[@sevensixty760]

I was powering my retracts via this method and although I haven't had any problems I will be changing to BEC immediately. Thank you so much for posting:)

[@dennisbaldwin]

sevensixty760 No problem. I didn't have any issues originally when testing on the bench, but a couple flights later my hexa went bye bye straight to the ground.

[@blackmennewstyle]

That's a tip i learned long time ago when i saw a lot of people flying airplanes :) It should help a bunch of people! I just got my taranis by the way! What a such fantastic radio

[@dennisbaldwin]

ABMNS PRODUCTION Glad to hear you got your Taranis. Hope you're enjoying it.

[@blackmennewstyle]

Dennis Baldwin Yes a lot :D

[@LuideMulumba]

For over a month I was having the same problem with my MinimOSD. It was powered off the APM, and the quad's OSD video would be fine, until the drone actually took off and put the FC to work, then I'd lose all overlay. Tried earthing cables and other things to no avail. Turns out the OSD simply needed it's own separate 5V BEC. Haven't had that problem again since.

[@sayniishpillay506]

Hey dennis, thanks for the video. Do you have a video on how to use the second method(using the AUX output on pixhawk to use the servo)? I know I need to use a BEC as well because the pixhawk does not provide power to the servo, but I'm a little confused on how to attach the BEC to the aux output.

[@MrTaz0079]

I did warn you about that m8, Happy to see you didnt do too much damage

[@dennisbaldwin]

MrTaz0079 Appreciate that :) One thing I failed to mention and was pointed out by Randy Mackay is that I need to remove the red power lead from the SBUS connection between the RX and Pixhawk. See Randy's comment for more detail. Thanks.

[@vyoufinder]

Do the retract motors get their power through the receiver/pixhawk? Or do they get power for the motors from the power distribution board or separately from the Pixhawk/receiver?

[@michaelguest9428]

Great video! Does the BEC provide redundant power to pixhawk too?

[@josephfishman]

Hello... Dennis is there a diagram that show the connect between the Pixhawk,retracts and a receiver? That also include the use of a BEC.

[@dennisbaldwin]

+JOSEPH MONROE This is probably the best one that I've found. Good luck and keep us posted on your build: planner.ardupilot.com/wp-content/uploads/sites/5/2014/06/common_Wiring_Pixhawk2.jpg

[@jeffreed1303]

Dennis, are you running 2 BEC, one for the X8R reciever and one for the Pixhawk?

[@76mosdef]

Wow... Good heads up! Is there another option for feeding in the necessary power needed? It would seem counter productive or even negates the purpose of running the sbus connection, for the added channel options!

[@dennisbaldwin]

Mosdef76 You can run it to an aux port on your Pixhawk but you'll still need to get power to the servo rail there. The only other option I can think of is running power to the retracts directly and separating the signal pin out to the receiver. Not sure if that will actually work and have found that putting the BEC directly into the receiver is generally the easiest way.

[@RoboTekno]

Yup, I learned about this problem when I had the flaps on a large Eflite Carbon Cub run off of a HobbyKing APM power module's BEC. I deployed flaps on one flight and watch the plane take a nose dive into the earth from about 100 feet, haha! Now I'll be passing control though the flight controller just as you've said :-P It's so obvious now. Never run servos though the 'power module/BEC/ voltage/Amp sensor.

[@dennisbaldwin]

RoboTekno Sorry to hear about your crash, but glad to know I'm not the only one that's done this. Makes me feel a little less dumb!

[@pauljohnson7538]

I purchased my retracts on eBay so I don't know who made them but they came with a module that has a bec that takes up to 6 cell and only one servo lead so never had any problems

[@dennisbaldwin]

Paul Johnson Nice. Wish mine had that built in!

[@MichaelKGizzonimo]

Thanks for the info Dennis. I think this happens a lot. As a simpleton I would have liked to see Your complete wiring of the BEC all the way to the retract servo? I am working on a OSD with current censor power distribution and worry about using PPM vs. old fashioned servo wires.

[@dennisbaldwin]

***** No problem at all. I actually have the BEC wired to my PDB so it gets power from the main battery. The Castle Creations BEC supports from 2S to 6S input and I'm currently running 4S. Another option would be to power it separately but I didn't want to do that. So the receiver gets power from the BEC, which in turn powers the retracts. Hope this helps.

[@MichaelKGizzonimo]

Dennis Baldwin OK! I see what You're saying. Thanks!

[@Mr17luchin]

hello, you have helped me a lot before and now I have the problem that my retractors did not get them to work with my pixhawk, you can further detail the procedure and configuration in mission planner, thanks

[@bryontrott]

Hi Dennis, where was the voice that says your connected or data link was lost, coming from? Was that from the Taranis radio?

[@dennisbaldwin]

Bryon Trott That was actually from the Tower app on my Samsung tablet. I use it sometimes for telemetry in the field and in this case I wanted to demonstrate the audible feedback when the Pixhawk locked up.

[@kentuckyfrier]

Just a thought. Isn't it nessesary to separate the bec sources? The 3dr powering the pixhawk only and the castle for the Rx and retracts. It appears they are in parallel. Like the reason why we cut all but one bec from our esc's.

[@dennisbaldwin]

kentuckyfrier Good thought and I had the same, but opted not to remove it. If you see the comment from Randy Mackay above then he confirms that it the red lead on the SBUS connector should be removed. I'm going to do that and will report back. Thanks for the thought.

[@danduesterbeck3589]

Can you post a video on setting up landing gear through pixhawk in the Aux ch. I am having trouble getting settings right in Mission Planner.

[@dennisbaldwin]

+Dan Duesterbeck Thanks for the question. I'm in the middle of filming a couple of videos but when I get some free time I'll definitely see if I can look into this. If you figure it before then please let us know how you did it!

[@jjssbailey]

Solves a lot of potential problems. Thanks.

[@dennisbaldwin]

John Bailey No problem. Thanks for watching.

[@marciocardenas9337]

what is the minimum volts the pixwawk needs before it brownsout? i am using a bec that supplies 4.9-5 volts and everyone is telling me that it is not enough especially when i start adding accesories to my drone. the only thing i will be powering with the bec other than the pixhawk will be my rx.

[@ExoPhotography1]

Hi, i have the exact same problem but with my Naza mlite and a Radiolink RD9S receiver. I Don't have a rssi port, but can I power my receiver via any port when running sbus mode? And also another solution - connecting my landing gear via the gimbal output on my Naza?

[@MrCorby4]

I am using RC pass through for pitch control of gimble with bec from one of the esc. It has been working so far. Should I be worried?

[@dennisbaldwin]

MrCorby4 I would definitely consider a BEC for it. See Randy Mackay post above regarding this matter. I'm going to be removing my power lead from the SBUS connection as well. Thanks for the question.

[@tomtoka]

what kind of landing gear did you buy? I got HML 650 and I don't like them. The main reason is - there is rubber between frame and landing gear, that makes the frame to shake, if you move it , and it is bad for landing

[@dennisbaldwin]

+Zycie w Californii These are the ones I'm currently flying with: amzn.to/1mHOIQA Yeah it sounds like the rubber you mentioned could be a problem.

[@jimmcminnsr6309]

Great video, if I understand, you're powering your RSSI with a UBEC to get the correct voltage for pins 9-16. Sorry to be so stupid, where are you powering your UBEC from?

[@jimmcminnsr6309]

So I picked up, I think you said you ran the power from servos 1-6 off the Pixhawk to the RSSI?

[@joburg76]

Hello again Dennis great video, does the same thing apply if using a naza mv2 with s-bus connection for the first 8 channels? and can i use just channel 8 for my retracts ? as I cannot get more than 7 channels out my dji tx hence the upgrade to the Taranis 9D+ and X8R Rx or do I have to set the X8R to D16 mode, please excuse my ignorance I have only just bought the Taranis and I am trying to learn as much as I can before i switch out the dji Rx from my 680 pro and add the retracts......thanks again I have learnt a lot from your vids

[@dennisbaldwin]

+George Abernethy Maybe this will help you out: kzbin.info/www/bejne/sInWp6aPl7xjb6c Good luck and let us know how it goes. Thank you for the feedback.

[@joeprt]

thanks sir so i only need to connect an uben on 5 volts to my recever and will avoid having problems ? thanks best regards i will try that and then post the result good flights to all

[@dennisbaldwin]

+joel bessa Yes sir. Give it a try and let us know how it goes.

[@guglielmodicarlo4139]

Im looking to install a drop mechanism, basically a servo to my Iris + which I'm sure you know runs pixhawk, which I think is the best controller out there so basically if I understood you correctly , I can use the receiver to plug my servo into, provided I feed the receiver with a ubec thanks, not much info on this on here, thanks,

[@dennisbaldwin]

+South West Florida Aerial Correct. That has been my experience...to supply an alternate power source so you don't run into any lack of power issues. Good luck with your project. Sounds very interesting!

[@davidringler7131]

Dennis is there a way of hooking up leds to my tarot 60 using my Taranis pls tx using x8r or l9r rx to turn led on or of?

[@dennisbaldwin]

david ringler Maybe this will help. Hope you're doing well. kzbin.info/www/bejne/iGm6iYWMl5uMbck

[@WillieMcphee]

now you tell me LOL rebuilding my hex after this exact incident from about 50ft up.. all props , one gear, gps mast, 3 arms, one motor,, 3D gimbal, all damaged 😂 rebuilt today, hoping new gyro will fix the gimbal,, DAMN LOL

[@dennisbaldwin]

Sorry to hear that but glad to know that you've rebuilt it. I hated seeing this happen to me before, but now we know! Good luck with the new gimbal.

[@bohemiandub5521]

hey dennis! Thanks for the vid! do you have a link for your earlier vid setting up the retracts?

[@dennisbaldwin]

+Bohemian Dub Here you go: kzbin.info/www/bejne/Z2SpY4udfratjLs

[@josecid9759]

Hi Dennis. The x8r works with an input of 5v, 100ma. You're using the Cattle Creation BEC that works on 5v, 10 amps. Are the amps important with this application? I had a simular situation with my s550 hex, using a NAZA M Lite. It flew into school property, and never recovered it. Building another one presently. Thank you in advance.

[@dennisbaldwin]

You should be fine with those amperage ratings. Sorry to hear about your crash. That sucks you weren't able to recover it. That's a horrible feeling knowing it's out there somewhere and you can't find it. Good luck with your new build.

[@tommygarcia9996]

It says on the wiki that the pix hawk and apm is meant to control Servos and not power them that’s why it freezes

[@rmackay9]

Thanks for sharing. As you've found you definitely shouldn't power a servo off the Receiver directly because essentially the servo is sharing it's power source with the flight controller's main CPU. In addition to the BEC, I think you should cut the power line between the receiver and the Pixhawk's RC input 'cuz I think it'll still cause little ripples in the power to the Pixhawk's CPU when the servos move. Basically the power to the CPU and the power to the servos needs to be separated.

[@dennisbaldwin]

Randy Mackay Thanks for the clarification on that, Randy. I was wondering about this issue when I installed the BEC and have already pulled the power lead. Appreciate it and all you and the dev team are doing.

[@rmackay9]

Dennis Baldwin No troubles, the videos are great.

[@GreyhatInfiltrator]

Dennis Baldwin The Copter Ardupilot website has a nice Wiki on How to Wire your APM or Pixhawk controllers Correctly. The Boards Themselves Were Never Designed to run a servo without a BEC, as it does not have enough power. Either Way, it could 've happen to anyone .... I am glad your Hex-copter is OK ...

[@tomtoka]

+TheGray Aviator I powered up my retreact form battery , and signal cables to receiver, ( 1 cable only) it was working, and in the field I noticed lost of power, with 100% power, i dropped, /?

[@GreyhatInfiltrator]

Zycie w Californii The signal wire should be connected to one of the outputs on your AMP/Pixhwak controller, not directly to the RX. Then you will need to use a BEC to power the output rails on your flight controller. Having said that, you should not experience anymore power drop out issues.

[@philipperichier5640]

hi Dennis. if i understand....you plug Bec from battery to Rssi and a servo or in your case servos retractable gear in receiver on 1and 2 which are 9 and 10 ( 16 ch ) then you choose ch 9 or ch 10 on your taranis.....another solution is to plug Bec in Aux rail on Pixhawk to get 5 volts then plug a servo on this Aux rail then choose with mission planner a ch 9 or 10 to move this servo........are my explanations correct...? thank's a lot and happy flights Philippe

[@dennisbaldwin]

Sounds like you have it figured out. Yes :)

[@dronesvisionsaeriennes]

Hi Dennis, i read the article about Arducopter...must i directly connect one of my ESCs to the "AUX " rail on Pixhawk, knowing that my ESCs are opto...and this will not work...otherwise may i directly connect a bypass in 5.3 volts from the original power module...? Thank's a lot, happy flights Philippe

[@dennisbaldwin]

Right. If you have OPTO ESCs they will not power the rail. If you can get 5V from the original power module to the rail then that should work. I'm just not sure how you'd do that. In my case I used a dedicated BEC like this one: www.amazon.com/gp/product/B000MXAR12 I hope this helps and good luck.

[@dronesvisionsaeriennes]

Hi Dennis, i'll try from original module tomorrow i think and i'll go back to tell you...! thank's a lot Philippe

[@dronesvisionsaeriennes]

Hi Dennis, i'll try from original module tomorrow i think and i'll go back to tell you...! thank's a lot Philippe

[@dronesvisionsaeriennes]

hi Dennis, i didn't understand all your comments but i need to add a servo to my Pixhawk...could you show me a schematic ...? why do you wire your rssi exactly...? Thank's a lot , happy flights Philippe from France

[@dennisbaldwin]

Hi Philippe, I hope you're doing well. This is probably the best resource I've found for attaching servos to Pixhawk. I've used it many times :) ardupilot.org/copter/docs/common-servo.html

[@dronesvisionsaeriennes]

Hi Dennis, thank's a lot for your answer...i'll probably try this next week, i get a lot of work this time...but i get on my drone opto Escs, therefore i think i have to wire a power supply to the rail "Aux " with 5volts max..? isn't it...? or add a zener diode maybe but i don't the differences between this 2 process...! Good evening Philippe

[@philipperichier5640]

hi Dennis in my previous message i forgot.....may i used another Bec or a Pololu step down to get 5 volts or is it mandatory with Castle Creation like your's ...?thank's a lot

[@dennisbaldwin]

You can definitely use a BEC other than the Castle Creations one :) Just make sure the voltage is stepped down to 5V.

[@bubu210741]

Hi Pixhawk get 5V power from one BEC and works fine. I just want to connect one powerfull (33kg torq 6V 130g) servo for steering (on aileron port) but pixhawk can give 5V on servo out connectors. How can i connect this higher voltage operation servo into pixhawk? Power: ground and + from another BEC (jumper 6V) and Sign: to aileron port of pixhawk. Worked enough operated well powerfull but when i started mooving the servo that started shaking fast right and left (seemed something noise mooved) I connected directly to aileron port of pixhawk (power, ground and sign from pixhawk) no shakes but servo is slow and weak on this bacause pixhawk have 5V power on this port. Thank you

[@dennisbaldwin]

+Gergely Patkó That's a really good question. It sounds like you have the right idea to power it separately and run only the signal wire. I'd look into that further and see if you can identify the source of the shaking. I will think about it some more and let you know if I come up with anything. Good luck with your project.

[@bubu210741]

+Dennis Baldwin Must connect grounds from 5V and 6V and wont shaking your servo. We did yesterday and try and finished that shakings. :) But you need to measure with any meter befor connect the grounds. G

[@justindevlieger9476]

lucky you I ultimately fried my Pixhawk from trying to run power through the sbus to my retracts.. still bewildered how to draw a separate regulated voltage to my retracts though.

[@dennisbaldwin]

Justin De Vlieger Yeah you're right. I definitely lucked out on this one. Can you not run a BEC to power your retracts? Just FYI in case you haven't seen it Tarot makes a retract controller, but requires their retracts for it to work: www.tarot-rc.com/index.php?main_page=product_info&products_id=1266

[@Mar1wan1]

If I plug a capacitor in my rx will this be solved? Does dji naza controllers have same issue?

[@dennisbaldwin]

mPky1 Well said.

[@Mar1wan1]

Thanks I thougth ita only lacking power for a bit..like shortly browning out

[@flytelaw1]

I am building a Tarot X6 with Naza-M V2, S-Bus on Xs-8R (like you have)...what do you recommend for the landing gear control?.....same BEC or is there another way? A million thanks!

[@dennisbaldwin]

I normally use a standalone BEC or one that comes off an ESC is another way to approach it. Good luck with your build.

[@flytelaw1]

Cool...ok...with respect to the "control" issues...do you use the Taranis' itself via XR8 or the PC interface with the software that comes with gimbal?...many thanks by the way:-)

[@NMHC1978]

I would like to put retracts on my ATG700AL6 hexacopter. I'm using a classic DSMX RX. The connection between my APM and RX is done thru 7 signal cables and one cable with Singal GND and VCC. I would like to control my retracts or by the APM if it is possible or Thru Port 9 on my RX.. I'm goinfg to put on my servor cable to the 2 servos (y-cable) and will connect the GND and VCC from my UBEC to that cable by connecting GND to GND VCC to VCC and Singnal. What do i need to do to not blow up my APM. on that 1 cable with GND Signal and VCC from my APM to the RX ... do i need to remove only the VCC to be safe ... what with the GND ? my GND is comming from retracts and UBEC but also from my APM ???

[@NMHC1978]

Marnix Verschraegen I think i also wil put a capacitor on my RX for possible bownouts (to be shure)

[@dennisbaldwin]

Marnix Verschraegen What I've done with my connection from the Pixhawk to my RX is remove the red power cable while keeping the signal and ground. My RX now gets power from the BEC and any voltage ripple in the retract servos won't cause any issue with Pixhawk since the power has been isolated. Hope that makes sense.

[@johncarr123]

We're did you purchase your pixhawk?

[@dennisbaldwin]

Jon Car I normally order them from 3DR or getfpv.com.

[@simenscott]

thats what happened to my airplane. It crashes 3 times just right after it takes off.

[@lijingwei0710]

there is a better solution with 3.3 beta firmware , just tested it yesterday , it works.

[@justindevlieger9476]

Jingwei Li what are you talking about can you explain it?

[@dennisbaldwin]

Justin De Vlieger I'd like to hear about it too.

[@justindevlieger9476]

Dennis Baldwin​ copter.ardupilot.com/wiki/common-optional-hardware/landing-gear/ found it here, looks like you use only signal wires and separate power getting its source from a ubec or separate battery

[@lijingwei0710]

Justin De Vlieger I just plug a ubec to the aux port which is unused