In the warehouse industry quality controls are of major importance. Clients rely on warehouse owner to keep sanitary controls and standard that won't compromise their business operation. One of the major challenges faced is how to prevent and early detect pests in a warehouse. Our IoT solution proposes a level 1 IoT system that uses Line Tracers and a human detector on a wheeled robot. Our solution is called PCAD system, that stands for Pest Control Auto-detection system, is a small and versatile autonomous solution that only requires to be placed at a start point and turn on via a web app. We believe that by running routine checks whenever the warehouse desires, may help increase early detection of pests in a crowded warehouse.

Step 1: Sensors and Actuators

In the design of our project we use the following:

Raspberry Pi 3 Model B V1.2
Micro SD card
2 x KY-033
1 x Human Detector
2 x DC Motors
2 x wheels
2 x 200 Ohlms resistors
2 x PN2222A6E transistors
2 x diodes
jumping cables

Refer to the picture above

Step 2: Putting It All Together

The complete circuit is in the picture above. In order to get to the operational parts connected, we found easier to test the mechanical piece first, that is the line following robot portion of this:

0. Set up cables to power and ground from the Raspberry Pi to a long breadboard.

Connected the circuit for the wheels, follow the image. For each DC Motor, please follow the instruction on: here (DC Motor circuit). We connect the wheels to pins 13 for left and 12 for right
Connect the KY-033 line tracers and set them up one inch apart from each other at the "front of the robot." We connected them to pin 16 and 19 for left and right, respectively.

The idea is that given a path marked by a black line in the middle of the robot, the robot should follow the line without getting off of it. Thus, there are 3 scenarios:

The line in the middle: Both line tracers will detect while portions (because the line is in between) and signal the wheels to move forward normally.
The robot is getting off to the left: That means that most the robot is leftward the line, we know this when the right line tracer detects the black line. In this case, we want to slow down the right wheel and accelerate the left one to cause a curve-like motion to towards the right.
The robot is getting off of the right: Conversely the case before, we accelerate the right wheel and slow down the left one.

Once this step is done, most of the device is finished. Lastly, we set up the Human detector to pin 21, and sends high signals when it observes a body of heat (rodent).