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DIY - Automated Clone Misting

If like me, you mist your cuttings while you are waiting for them to root, you know how important it is not to wait too long. Nothing worse than coming in and seeing them all slouched over, dying of thirst...  The good news is they usually perk up once you mist them...

I try to have clones going all the time, so that means constant misting....

I have a drawer full of Servo's left over from my days of flying radio control planes (and helicopters, multicopters, cars, boats, sailboats, trucks, crawlers, and I'm sure I forgot some) 

So, armed with a servo and a spray bottle, an idea started to form in my head...   It took me a while (I let it simmer in the back of my head) because I couldn't quite grasp how it would fit together so that the servo could actually pull the trigger...

Here's what I came up with...

I mounted the servo and the bottle on a piece of "aircraft plywood" which is just a high quality thin plywood used for building model airplanes. Anything would work here...

I cut the hole in the wood so the bottle would fit tightly into it from the bottom, and then just screw the top onto the bottle nice and tight and it holds the bottle and wood in place...

I cut a couple pieces of flat foam I had to fit inside the cap, since it isn't going to screw on all the way because of the wood. This ensures I can tighten it up snug...

I cut a rectangular hole in the wood to hold the servo so that it sits flush to the bottom of the wood, this way the wood holds the servo from twisting... The servo is also screwed to the wood with wood blocks on the bottom side to hold the screws.

Here it is with the bottle and the servo in place and tight...

Finally, the trigger, I poked a hole through it with my soldering iron so that the rod from the servo could hook around into the hole so it would not slip off.

Because the servo is fairly heavy, this whole thing just tips over unless it's full of water.  I'm also a little worried about how long the water will last in the bottle, probably a while, but, I decided to extend the "pickup tube" through a hole in the side of the bottle. This will allow me to put the other end in a larger reservoir of water. This also allowed me to drill a hole in the bottom of the bottle and screw the whole thing onto a block of wood which will hold everything in place.

For my initial prototype, I just used my test module, a Wemos Mega 2560.  I wrote a very basic sketch that simply moves the servo arm back and forward again every 5 seconds...

Here's the code...

// We are using the SERVO library...
#include <Servo.h>
// create a servo object
Servo cloneMisterServo;

int cloneMisterServoPin = 9;
int servoAngle = 0;
void setup() {
Serial.println("Grow By Wire Clone Mister (Proof of Concept)");
Serial.print("Compiled: ");
Serial.println(__DATE__ ", " __TIME__);
void loop() {
void squirt()
for (servoAngle = 0; servoAngle <= 120; servoAngle += 10)
for (servoAngle = 120; servoAngle >= 0; servoAngle -= 10)

As for hooking the servo up to the Arduino, a servo has 3 wires, Black, Red, and usually either orange, brown,  or white for the third. Black is ground, Red is 5v, and the third (yellow, brown, or white) is the signal line, this we hook up to pin 9 on the Arduino.  The red and black are hooked up to an external 5v power source since the servo draws more current than the Arduino can provide when pulling the trigger... Make sure the external source and the Arduino share a common ground.  

I'm using a fairly hefty servo, just make sure you use something strong enough to pull the trigger, preferably with metal gears so they don't strip.

I'll probably wrap it in wood so it's like a small wooden box with a spray top on it...  Right now, if it's not full of water, it will tip over because of the weight of the servo...  

I will probably cut the bottom of the bottle off, and attach plastic tubing to the sprayer intake tube, and place it in a larger reservoir of water so it is capable of running for days without needing to be refilled.

That's it, hope this inspires you...

Update June 22, 2019

  • Added Block of wood to create a stand because it kept falling over.
  • Extended "pickup tube" so it can draw water from a larger source

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