An Embedded System for Detecting Choking of Boots of a Seed Drill

Choking of seed drill during sowing of wheat generally occurs due to excessive soil moisture, weeds or agricultural residue present in the field. The developed embedded system for detecting the choking of boot comprised three units: sensing unit, processing unit and alert unit. A direct incidence infrared (IR) emitter and IR receiver were selected for detecting choking of boots of a seed drill. An Arduino Mega 2560 microcontroller board was used to process the detected choking output signal of this sensor and to produce signal, using the uploaded programing code in the microcontroller board, to alert the about choking of boot of the seed drill. IR emitter and receiver were fixed opposite to each other 180° apart at the bottom end of the seed tube. The alert unit comprised audible (continuous piezo buzzer) and visual (red LED). The performance of the developed system for a single row seed drill was evaluated in the laboratory with wheat seeds at different seed rates. The developed system detected choking, independent of seed rate in all the boots of the seed drill. However, there was a time gap observed between choking actually occurred and sensed by the developed monitoring system. This was due to height at which the emitter and receiver were fixed from the bottom of the boot. The system produced both audible and visual signals successfully to alert the operator about choking of the boots. Schematic diagram of developed embedded system for detecting choking o boot are given in Fig. 1.

There are two type of IR sensor, one is indirect incidence infrared sensor and another direct incidence. In indirect incidence both the emitter and receiver are placed side by side. When an opaque object is place in front of emitter and receiver, emitted radiation of emitter reflects back and incidence on receiver consequently output voltage of sensor change (HIGH to LOW) as proportional to intensity of incidence radiation on receiver. In direct incidence infrared sensor, emitter and receiver is fixed 180˚ apart (i.e. opposite to each other). When an opaque object is place in between emitter and receiver, emitted radiation of emitter reflected back consequently output voltage of sensor change (LOW to HIGH). Same concept of direct incidence infrared sensor has been used in this study. An IR LED and receiver were mounted rigidly in 25.4 cm diameter pipe such a way that emitted radiation directly were incident to the receiver which is shown in Figure 2a. When boot of seed drill was choked accumulated seed inside the pipe as opaque object in between emitter and receiver, emitted radiation of emitter either reflected back or observed by accumulated seed in the pipe consequently output voltage of sensor was gone high to low which is shown in Figure 2b.

The circuit diagram of the developed IR sensor for detecting choking of boot is given in Fig. 3. R2 and IR LED were the source of IR light and it was received by the IR receiver. When IR ray falling on the IR receiver was interrupted because of the accumulation of seed between IR emitter and IR receiver, the LM358 IC compared the signal before and after accumulation of seeds between emitter and receiver with a specified voltage level depending on the setting of the potentiometer. The comparator gave the output signal after comparing these signals and these signals were then fed to the microcontroller board as well as to the red LED1 (Fig. 3). Components details were used to develop the IR sensor are given in Fig. 3. Mounting of IR emitter and receiver in the boot of seed drill is shown in Fig. 4.

The circuit diagram of the developed embedded system for detecting choking of boot in a single row of metering mechanism is shown in Fig. 5. The following components were used to develop the circuit of the embedded system for detecting choking of boot in a single row metering mechanism:

(i) Arduino Mega 2560 microcontroller board (ii) 1 × DPDT (Double-Pole, Double-Throw) switch (iii) 1 × Cont. Buzzer (Rated voltage = 3 V) (v) 1 × Red LED (vi) 1× 1 Ω resistor (vii) General purpose PCB (viii) 9-volt Battery.

Detection of choking of boots of a seed drill was indicated by both visual and audio forms to alert the operator for efficient sowing operation. The alerting system comprised one audible (cont. buzzer) and 1 visual outputs (red LEDs) indications. Connections to these red LEDs and buzzer are shown in Fig. 3. Performance of the developed embedded system for detecting choking of boot in a single row seed metering mechanism of a seed drill was evaluated at different seed rates and speeds of metering roller using the developed laboratory setup. The boot of seed drill was choked (by closing the outlet of 28 mm pipe, green colour pipe, Fig. 4. Seeds were accumulated inside the pipe from the lower end thereby obstructed the emitted IR light between IR LED and receiver. When the sensor detected choking of boot of seed drill, digitalRead of program gave a binary output ‘0’ (Low voltage, cont. buzzer ON, red LED ON) and when the sensor did not detect choking of boot of seed drill, digitalRead of program gave a binary output ‘1’ (high voltage, cont. buzzer OFF, red LED OFF).

Output data on choking by the developed embedded system for a selected seed rate of 100 kg/ha at a fluted roller speed of 35 rpm were taken for a period of 100,000 ms. During this time blocking of the boot was made at 20,000 ms and 60,000 ms and the output from the system with time is shown graphically in Fig. 6. When seed droppings to the tray was interrupted by closing the outlet of pipe after 20,000 ms, indication of choking by the system started at 22,405 ms corresponding to a binary value ‘0’ as shown in Fig. 6. Thus there was a delay of 2405 ms in detecting choking by the developed system. Similarly, attempts were made to choke the boot at 61,000 ms whereas choking was detected by the sensor at 63,609 ms. Hence, the delay in detecting choking was 2609 ms (Fig. 6). This delay in sensing was due to fixing the IR LED at a height 15 mm from the bottom of the pipe. Hence, time was required to fill the boot with seeds to the position where the IR LED and receiver were fixed to detect choking. The developed embedded system can be replicated for multi-row seed drill for detecting the choking of boots of a tractor drawn seed drill.

int Pin1=2;

int buzz1=12;

unsigned long time;

void setup() {

pinMode (Pin1, INPUT);

pinMode (buzz1, OUTPUT);

Serial.begin(9600);

}

void loop() {

int sensorValue1 = digitalRead(Pin1);

if (sensorValue1==0){

digitalWrite(buzz1, HIGH); }

else

digitalWrite(buzz1, LOW);

time = millis();

Serial.print(time);

Serial.print("\t");

Serial.print(sensorValue1);

Serial.print("\n");

delay(100);

}