Pixhawk 2.1 Agro Sprayer

Hi All,

Im trying to build and Agro Drone with Pixhawk 2.1 and im facing couple of problems with the pump controller and i have done the wiring and attached the pump controller switch …i have set up the params as for this link http://ardupilot.org/copter/docs/sprayer.html# sprayer but i realized that the pump don’t functioned. I checked the params and fount nothing wrong with ether the params or the with the wiring, I have tried channel 9 and 8. and the servo 9. have any one else come across any similar issue
link to the pump controller is below. kind help is appreciated

link : https://www.aliexpress.com/item/32782390517.html?spm=a2g0o.detail.1000014.41.347e7ec83qp10h&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.13338.128125.0&scm_id=1007.13338.128125.0&scm-url=1007.13338.128125.0&pvid=bcdf9234-a871-4329-9498-5186ffe851e7

Have you tried the pump controller plugged into a normal RC receiver with a 5v to 6v supply?

What I found is that a lot of PWM switches and relays actually need a 5v signal to work reliably.
The signal output on the Aux ports I have measured at 3.3v.

Hi Thanks for the feed back…

I haven’t try’d it actually. Because pump need to adjust its RPM speed as the drone speed increases… Ill just give it a try to see if this thing at least turning on. … At the mean time is there any way we can get 5V out from aux channels?


It worked with the direct connection to the receiver… Now how can i get the 5v out from AUX rail? at the mean time ill do some research on that as well…cause i need to adjust the pump speed in relation to the speed of the drone…


Suggest plotting the servo output to ensure that it is being activated
by the autopilot.

You could also attach a 9g servo to that port and make sure it wiggles.

If that all works you’ll need a level shifter, probably.


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To get 5v on your AUX rail simply connect an ubec to your sevo rail


@hosein_gh that’s not quite right.
In this case, the issue is not the bus voltage but the logic voltage on the signal pin.
There’s a solder pad inside the cube that can be bridged to set the signal to 5V (this is actually the difference between “Cube Black” and “Cube Green”).
// edit: I actually don’t know if that solder bridge effects the Aux levels. @proficnc ?


No, the 5V option is only for the io port

Servo city sell signal converters that do this per channel

But as you said, this is signal voltage, not rail voltage

A logic level converter might do the trick.

@james_pattison yes i misunderstood
@skhyperion mean is 5v is on signal

Just give 5volts from a bec to the pumb and connect the signal wire on the aux port…

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If you don’t manage to get work your pump controller, then just buy a BRUSHED motor ESC, they usually work with 3v3 signal level, and can control the brushed motor in your pump.
(In the rare case that your pump has a brushless motor, then it is more easy to replace the controller)


Guys Thank You So Much…It Worked… I just jumped a (+) Pin from the empty 5V rail in the RC RX to the (+) pin on the Cube AUX rail keeping the (-) as the common ground, and the pump started to work…

Thank You Soo Much For All The Friends Who Took a Bit Of Your Valued Time To Drop A Workaround …
So Much of Love From Sri Lanka


Be aware that the RC 5v pin is specifically for ONLY powering standard receivers and is not like a servo supply.

Exactly. DO NOT power servos from the rc pin. You’ll likely destroy the flight controller.

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Absolutely! Do not use the RCIN power for anything other than a basic RX.

You will destroy the flight controller

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You could use a zener diode too prevent the spikes exceed 6 volts but the best is too use a bec to give power to the servo

A zener will not help here at all! You must NOT power anything off the RC in port other than a receiver

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Thank You Soo Much…for the advice. sure will use a BEC. Thank god FC is intact .


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that is great news! all the best

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