Help adding a rc servo to operate micro spray tank

[SteveH]

I have had my P3A since January and love it. I use it for agriculture and of course enjoyment. I scout my fields, check conditions and crops or weed problems in all my fields. It's great! I would love to add a "simple" spot sprayer to my drone. I've seen the Agras, and $10k is a bit much! I don't need the gps routing and so on. I just want to be able to fly over a small patch of weeds and spray dribble some herbicide on it. We also keep our creek bottoms free of invasive plant species and this would be ideal to fly over to that on bad plant 100' out in a swamp and be able to apply the herbicide. I don't have any experience with servos and RC but from what I've seen it can't be that hard to do. Just a simple servo, that can be controlled remotely to open a small valve or pull a trigger on a little plastic tank. Think "small" water bottle sized tank, I'd probably pressurize it with a few pounds of pressure to enhance the dribbling of herbicide. Also thought about clear tubing hanging down a couple of feet from the drone with a nozzle on it to get a bit away from the rotor drafts. Obviously i'll have to test it and see what the rotors do to the spray. Looking for thoughts and ideas and exactly what to buy servo/rc wise. Kind of clueless.... self powered, remote controlled servo to push, pull, or rotate . . . ? Mini easy to operate valve?

 

[Monte55]

A gallon of water weighs about 8.3 lbs. You'll never be able to carry enough spray, plus weight of tank, tank mounts, sprayer, pump, servo etc to really make it a worthwhile venture unless the liquid payload is so small you want to spray a weed or two just for fun.

 

[N017RW]

In addition to Monte's evaluations is the fact that Phantoms don't lend themselves well to such additions. There are some workarounds using systems that are switched by detecting arm LED status but you'll need quite a bit of tinkering to implement.

 

[SteveH]

A gallon of water weighs about 8.3 lbs. You'll never be able to carry enough spray, plus weight of tank, tank mounts, sprayer, pump, servo etc to really make it a worthwhile venture unless the liquid payload is so small you want to spray a weed or two just for fun.

I'm looking at an 8 0z. sized (half size drinking water bottle), so the weight of spray "tank" and liquid wouldn't be much of an issue. How concentrated the herbicide is will dictate how much one could spray. On the invasive species in sensitive areas (wetlands or hard to get to spots) it would be extremely beneficial to take out that handful of invasive plants. concentrated enough, a few drops will kill the target. I'm not looking to do large areas. Maybe 20 plants here and there. I'm thinking the servo and power supply for it couldn't be that much weight . . ?

 

[Jayfdee]

Maybe a standalone arduino board with RF module. The arduino can be very small indeed,just the programmed chip if necessary, and easy to code for a servo. Very cheap solution.
As others have mentioned,it all adds weight, so not too practical.

 

[Monte55]

I'm looking at an 8 0z. sized (half size drinking water bottle), so the weight of spray "tank" and liquid wouldn't be much of an issue. How concentrated the herbicide is will dictate how much one could spray. On the invasive species in sensitive areas (wetlands or hard to get to spots) it would be extremely beneficial to take out that handful of invasive plants. concentrated enough, a few drops will kill the target. I'm not looking to do large areas. Maybe 20 plants here and there. I'm thinking the servo and power supply for it couldn't be that much weight . . ?

Some things in vegatationt or weed killer are corrosive. I wouldn't want my Phantom exposed to it.

 

[yorlik]

Some things in vegatationt or weed killer are corrosive. I wouldn't want my Phantom exposed to it.

As a tree farmer, I spray about 300 gallons roundup per year. I never clean sprayer, tank, pump, lines. Just run till out, typically 30 gal per tank... in 20 years I have never had a single metal piece corrode. So my opinion is he does not have to worry about that aspect, assuming he uses roundup or equiv.

Sent from my SM-G900V using Tapatalk

 

[Monte55]

As a tree farmer, I spray about 300 gallons roundup per year. I never clean sprayer, tank, pump, lines. Just run till out, typically 30 gal per tank... in 20 years I have never had a single metal piece corrode. So my opinion is he does not have to worry about that aspect.

Sent from my SM-G900V using Tapatalk

I have used Weed B Gone and Round Up and similar products for many years. The brass spray nozzle can get corroded with green crap. I have a 15 gallon sprayer on my ATV. After a couple of weeks a growth will happen that clogs the intake screen. On my pump up sprayer, the leaking liquid will stain concrete and if laying on a piece of metal will leave a white crusty residue.

 

[SteveH]

As a tree farmer, I spray about 300 gallons roundup per year. I never clean sprayer, tank, pump, lines. Just run till out, typically 30 gal per tank... in 20 years I have never had a single metal piece corrode. So my opinion is he does not have to worry about that aspect, assuming he uses roundup or equiv.

Sent from my SM-G900V using Tapatalk

Exactly. I'm not at all concerned about corrosion. I have crop farmed for decades, round up or the generic CornerStone herbicide doesn't corrode and I use brass nozzles. Green on brass or copper (verdigris) is from water itself. Now fertilizer would be a different story...
Any way back on topic
Just looking for a way to open and close the flow remotely.

 

[bryan_m]

Define how much it would need to hold. You might want to check out the firefighting drone that FlightTest built :

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Though if you are hitting only weeds it would make more sense to have it point straight down and hover over to spray. Much more practical and accurate. However that would never work well with a fire.

 

[SteveH]

Just found this by gimbal guard....

Gimbal-Guard

I would just need to use the stroke of the pin to open and close a tiny valve on a tube or something to interrupt flow. I guess my other thoughts were a steering mechanism out of a cheaper RC car to open/close a micro valve or even just to tilt/untilt the a small bottle over a target.

 

[N017RW]

Seems to me your first issue is getting a [control] signal to actuate whatever you decide on.
The Phantoms are a bit 'closed off' and do not have 'hooks' or other easy ways to add such mechanisms.

 

[Eshorvath]

You also need to apply for and receive authorization from the FAA.