Hydroponic Pump From Recycled Battery Operated Weed Killer Sprayer




About: The best things in life are dangerous.

This Instructables will show how I recycled an old battery operated weed killer sprayer in to an automatic hydroponic pump, or to pump any light fluid for any purpose.
You will need one used battery operated weed killer sprayer, wash it out with liquid dish soap a couple times, don't want to leave any chemicals in in.
An x-10 universal module.
Some wire for remote switch.
1/8" I.D. length of clear tubing.
A rechargeable 7.2 V battery.
The sprayer is battery operated, it holds 4 AA (6 volts) batteries but never seemed to work great, in this instructable I upgrade the power source to 7.2 volt rechargeable battery, which could be charged with a small solar panel.
I used an x-10 universal module to control the pump. X-10 automation software to run pump 4 times a day at regular intervals.

Step 1: Disasemble the Sprayer Gun

Locate the screws holding it together, remove them. Pry the bottom open and work towards the top, the top has snap fit bosses on the inside. It will pop open when persuaded enough. Inside we find a small dc motor driven pump, a trigger switch, battery compartment and the spray nozzle. To remove the pump, I cut the wires.

Step 2: Pump Nozzle Modification

We now can remove the spray nozzle,use a screw driver and pry between the pump housing and the clear plastic nozzle tube and collar. Use care it's all plastic. After you get that off attach a long piece of 1/8"clear tubing.

Step 3: Swich and Power Modification

These steps will show how to bypass the existing trigger switch and adding a remote switch. Also wiring in an extension from the battery compartment to a higher voltage rechargeable battery. These steps could be skipped if you use the existing battery compartment and the trigger switch as is. But I wanted to control the pump remotely, and using a external power source I can give the motor more voltage. I tested this pump and it will turn on 6 volts minimum, but it was able to take up to 12 volts. 12 volts seems a little much as it spun insanely fast. With the right nozzle and 12 volts this would make a hell of a super soaker. But that would be another instructable.
First identify the positive tab on the battery spring, that is where you need to solder or connect one lead from remote switch and positive lead of a power source 6-12 volts DC. The negative lead from power will connect to the black wire,and the negative side of the motor. The other lead from remote switch will connect to positive side of motor ( shown in the next step.)

Step 4: Switch and Power Modification 2

Here we see the positive side of the motor connects to one lead from the remote x-10 switch, the other lead from switch connects to positive wire from the power source. The negative wire from power connects to - side of motor. Test it before you position the wires for reassembly.

Step 5: Reassembly

You will need to make the notches bigger that the wires and supply hose to pump will fit through. Make sure the hose is not pinched off when you reassemble the two halves. That's it, your done! Now you can remotely water your hydroponic garden with it, like me, or you can use it to pump whatever remotely.
Remember if you use this for garden or fun be sure you wash the container well before use.



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    12 Discussions


    7 years ago on Introduction

    this is like something I need to spray glitter in intervals, I would like to hook it up to a sensor. do you think, as I have no idea what I'm doing you could hook up a similar type or rig, with something that has a bigger tube and nozzle to allow glitter to pass through? does it have to be liquid?

    3 replies

    Reply 7 years ago on Introduction

    This idea is for liquid , spraying glitter would require air and a solenoid to turn air supply on and off via a sensor as you require. I know powder can be effectively sprayed using low pressure air . Look up spray powder units for offset presses. Glitter would require more air and a tube and nozzle to handle the particles of glitter. If you could explain what would trigger a sensor and how big each glitter piece is then I could try and help more. The glitter would have to be dry and uniform in size.


    Reply 2 years ago

    hi, whats the rubber tube material made from? I want to know...and is it durable and flexable so it wont tear when moved about


    Reply 7 years ago on Introduction

    oh thanks! people would trigger the sensor, entering the space or I might just use a timer. do you think a paint sprayer might work with a big enough nozzle. the glitter will be dry and would prefer not uniform but can do if thats what will work. the glitter I'm thinking will be fairly big or even small star shaped so it won't get too into peoples eyes etc as it will spray onto people as they walk in. I just need something that can hold a fair bit but not too strong in pressure and pretty cheap if possible.
    thanks for the reply!


    5 years ago on Introduction

    great idea. I have a swiffer spray mop with a battery operated sprayer, I bet I can use it the same way. thanks for posting this.


    7 years ago on Step 5

    wow how long did it tak u to flush out the bad stuff ? cus i hav bug spray


    Reply 9 years ago on Introduction

    im just saying that i would try to get rid of the green handle and maybe just mount the pump to the lid of the container only the top of the gun is used for the pump maybe you could cut the bottom of it off and glue the top to the lid btw im not trying to be rude just expanding on the concept


    Reply 9 years ago on Introduction

    That's cool , I left the handle in tack as it has a clip that attaches to the container, and this will still function as before if you put batteries in the handle and press the trigger. I didn't think it rude just didn't understand, feel free to expand on the concept. I did, and made a piece of landfill into something useful. Cheers!


    9 years ago on Introduction

    An excellent re-use for an otherwise environmentally-unfriendly product! Nice.