This project challenged me for two main reasons; firstly, because I began making it in 9th grade, when my experience with electronics and programming was very little and secondly because of the multitude of different components and wires used.
This radar consists of an ultrasonic distance sensor mounted on a servomotor that is panning right and left, an ATMEGA328 chip, 35 LED’s used as a display, 5 74LS373 chips used to aid the display, a voltage regulator, a quartz crystal and some resistors and capacitors. The ultra-sonic sensor scans a quadrant of radius 70 cm. When an object is placed in that area, the distance sensor records the distance from it and depending on the angle of the servo motor, the LED(s) corresponding to the position and size of the object light up. As the servomotor pans right and left, the columns of the LED’s light up and then turn off. The ATMEGA328 chip is the microcontroller and processes the information. However, because there are not enough outputs (37), I used the 74LS373 chips, which are octal-D tri-state flip-flop latches. This reduces the outputs needed to 12 (7 for each row of LED’s and 5 for the latches of the 74LS373 chips). The quartz crystal is used as an external timer for the microcontroller, while the capacitors “even-out” any disturbances in the voltage.
One problem that I faced during the making of this project was that in the beginning I used an infrared distance sensor instead of an ultrasonic one. This sensor had two serious drawbacks; first of all, the relation between the voltage output and the distance of an object was not linear, which made it less practical. Secondly, the infrared sensor output greatly depends on environmental conditions such as the amount of sunlight present. As a result, I decided to use an ultrasonic sensor. Also, something that was really tiring was the need to use and solder a multitude of small wires (approx. 80) in a very limited space.
Even though this project took me almost 2 years to complete and was more difficult than I expected, I learned a lot in the process it and I am proud to present it in working condition.
