Table Ultrasonic Radar (Owl Variant)

Owls have an excellent hearing aid. Their ears can detect minimal noise. Each owl need only to rotate her head to scan the space around this predator bird. The Arduino platform also has an interesting sensor – ultrasonic HC-SR04. This device emits an ultrasonic impulse and according the detection time of received reflected signal gives us ability to calculate the distance to a nearest object on a current direction. Let's make a robo-owl to detect a new object in a room. Robo-owl will turn his head by a stepper-motor and fix the distance to obstacle. During the next scan our device will compare the changes and according to a maximum difference get an 'interesting' direction. This direction will be the current owls head direction till the next scan.

Materials:

• 5 cardboard cans (with covers) for melted
  cheese (D = 111 mm, H = 22 mm);
• any plastic cover (D = 77 mm, t = 2 mm);
• any plastic plate (60 x 80 mm, t =1 mm);
• plastic packaging holder for screwdriver;
• postal envelope;
• nuts (D = 3 mm, D = 2 mm);
• bolts (D = 3 mm, D = 2 mm);
• washers (D = 3 mm, D = 2 mm);
• PVA glue;
• cables (Dupont M-F, 10 items );
• Arduino Uno;
• 28BYJ-48-TE118-Stepper-Motor;
• ULN2003-Driver-Module-Board;
• HC-SR04-Ultrasonic-Module;
• AC-DC power supply 9V/1A.

Tools:

• screwdrivers set;
• office knife;
• scissors;
• awl;
• needle file;
• ruler;
• pencil;
• eraser;
• pliers;
• USB-cable;
• computer with Arduino IDE.

Each cardboard can will be a separate level of our construction. Level-0 – base. Level-1 – Arduino base. Level-2 – cable storage. Level-3 – Stepper Motor and Driver Module slot. Level-4 – the head of our hero with Ultrasonic sensor (owl or somebody else). You need to make appropriate holes in all part to conduct cables. Use screws to connect electronic boards to a cardboard cans. You can use both glue or screws to connect levels between each others.

Check the assembly and all electronic connections according the scheme. Next you need to write the program code into your Arduino using appropriate IDE and USB-cable. We will use special library for Ultrasonic sensor (iarduino_HC_SR04.h (https://iarduino.ru/file/283.html or direct link)) MIN_POS = 16 and MAX_POS=16 – the limits of sensor rotation by 90 degrees to each side from initial position. After each scan the head with a sensor turn to position with a maximum difference between current and previous measured distance. The program will run the scan process each 5 seconds.

Test your device with USB-connection to computer. Perhaps you need to make some changes in a code (your own project can be more intelligence then basic one). When you get appropriate result disconnect computer from you Arduino and plug AC-DC Power Supply.