Pesticide Sprayer Spider Robot with Grass Cutter

Pesticide Sprayer Spider Robot with Grass Cutter

Image: Filling sprayer tank on tractor with Banvel (1985).jpg by USDA NRCS via Wikimedia Commons, Public domain

How It Works

• The robot's legs (or, in a simplified build, a low-ground-clearance wheeled chassis) let it move steadily across uneven, unpaved field surfaces under RF or Bluetooth remote control.
• A forward-facing camera module feeds frames to the controller, which uses basic colour-thresholding (or a lightweight vision model on a Raspberry Pi variant) to flag weed-density regions distinct from crop rows.
• When a weed region is detected directly ahead, the controller energizes a relay that runs a small submersible pump, drawing pesticide from the onboard tank through a nozzle aimed at that patch only.
• The front-mounted cutting motor and blade assembly can be engaged independently to trim grass and low weeds mechanically, giving the robot a dual spray-and-cut mode for denser overgrowth.
• A float-level sensor in the tank flags low chemical levels on the controller/remote, reducing the chance of the robot running dry mid-row and needing a full stop-and-check.

Components

Arduino Uno/Mega (or ESP32 for onboard Wi-Fi telemetry)
ESP32-CAM or similar camera module for crop/weed differentiation
Color or IR reflectance sensor (secondary detection input)
DC gear motors + wheels or servo-driven leg linkages (spider chassis)
Motor driver module (L298N / BTS7960)
Mini submersible pump + spray nozzle + relay module
Small pesticide/water tank with float-level sensor
DC cutting motor with rotary blade guard
RF or Bluetooth (HC-05) remote control module
Li-ion/LiPo battery pack + chassis frame

Applications

• Precision spraying on small and mid-sized farms
• Nursery and greenhouse weed and pest management
• Reducing farm worker exposure to chemical sprays
• Combined lawn and field maintenance in one machine

Advantages

• Targeted spraying cuts pesticide usage and input cost compared to blanket spraying
• Dual spray + cut functionality removes the need for two separate machines
• Remote operation keeps the operator clear of chemical drift
• Low-clearance, multi-point contact chassis handles uneven farmland better than standard wheeled sprayers

Sample Code — Weed-Triggered Spray Relay

// Simplified spray-trigger logic — Arduino
// weedSensor: HIGH when the color/IR sensor flags a weed patch ahead
int weedSensor = 2;
int pumpRelay  = 7;
int cutterRelay = 8;
int tankFloatSwitch = 4; // LOW when tank level is low

void setup() {
  pinMode(weedSensor, INPUT);
  pinMode(tankFloatSwitch, INPUT_PULLUP);
  pinMode(pumpRelay, OUTPUT);
  pinMode(cutterRelay, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  bool weedDetected = digitalRead(weedSensor) == HIGH;
  bool tankOk = digitalRead(tankFloatSwitch) == HIGH;

  if (weedDetected && tankOk) {
    digitalWrite(pumpRelay, HIGH);   // spray this patch only
    Serial.println("Weed detected -> spraying");
  } else {
    digitalWrite(pumpRelay, LOW);
  }

  if (!tankOk) {
    Serial.println("Tank level low - refill needed");
  }

  delay(150);
}

Related Research

• Precise Robotic Weed Spot-Spraying for Reduced Herbicide Usage and Improved Environmental Outcomes — arXiv