In most cases, a fence or a garden wall is not enough to prevent unwanted animals visiting your garden. This is particular true for gardeners who like to grow vegetables. Animals such rats and birds might see your vegetables as free food. Or your neighbourhood’s cat might have taken a liking to your lawn as its personal toilet.

One solution to deter these “unwanted guest” is by shooting at them with a water gel pellet. The garden defender has a webcam that continuously scans your garden. When an “unwanted guest is detected”, the garden defender with aim and shoots.


  • Detect unwanted guests: OpenCV and a deep learning algorithm “YOLO” were used for object detection.

  • Aim and shoot: When an unwanted guest is detected, will aim and shoot

  • Garden surveillance - large field of view: Robot will continuously move the webcam left and right to maximize the field of view when an unwanted guest not detected.









RequiredRPI 480180
RequiredPCA9685 Servo Driver818
RequiredLDX-227 Servos21242
RequiredGel Blaster40140
OptionalPrimer Black10.79110.79
OptionalPaint Silver6.8916.89
RequiredHex Flat Head Bolt Metric6.9916.99
RequiredPLA Filament18.04118.04
RequiredUSB Webcam14.99114.99
RequiredRelay breakout4.9914.99
RequiredScrew kit13.59113.59
RequiredThreaded inserts7.4917.49
RequiredBearing 6905-2RS3.9913.99
OptionalLed ring 38mm8.9918.99


  1. 3D printer
  2. Tweezers
  3. Soldering Iron
  4. Glue for plastic parts
  5. Phillips screwdrivers
  6. Hex key set (Millimetric)
  7. Sandpaper

Build and assembly

1.- 3D print STL file

2.- Using the soldering iron insert the threaded inserts into the plastic parts. They must be flush.

3.- Build blaster: Insert Neopixel led rings with their cables on blaster cases, and route the cables.

4.- Add the servos cable and route it inside the blaster case

5.- Place the camera and blaster inside de blaster case. Double check that the cables are routed correctly.

6.- Align the camera cable and close the blaster case. Optionally, you can add cord protector wire loom.

7.- Add x7 M3 screws using a hex key M2.5.

8.- Paint plastic parts. Optionally, first, use a primer.

9.- Add x4 feet into the main base and secure them with x4 M5 screws using a Hex key M4.

10.- Add the switch into the main base and secure it with x2 M2 screws using a Phillips screwdriver.

11.- Add the servos driver into the main base and secure it with x2 M2 screws using a Phillips screwdriver.

12.- Add the relay modules into the main base and secure it with x2 M2 screws using...

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