This lock-down due to the COVID-19 crisis became a new reason of boredom for me, but also inspired me to create new things- I made a gadget called a 'Wearable Social Distance Detector Gadget', and now I wanted to build something new. This gadget is called an 'Instant Human Height Detector Gadget'. It has the main body of a mobile box, with an LCD (Liquid Crystal Display) screen at its front, which displays the height measured based on the calculations made by the gadget, based on the ultrasonic sensor. The Arduino Board is programmed such that the maximum height it can measure is six feet (the maximum height to be measured can be set in the code), i.e., the gadget must be fixed on the wall at a height of six feet.
For better understanding of how this functions, here is a video on how it works.
The following are the steps in making this gadget-
1. Connecting the Arduino Board to the LCD Screen
The first step is to connect the Arduino Board with the LCD screen, while also connecting a potentiometer, which helps in setting the clarity of figures displayed on the LCD screen. These components shall be connected using a breadboard. Below, you will find the imagery of how to perform the necessary connections.
2. Connecting the Ultrasonic sensor to the Arduino Board
The next step is the Ultrasonic sensor and Arduino Board connection. The Vcc(5V) and the Gnd(0V) pins on the sensor must be connected to 5V and Gnd pins on the Arduino Board. The trigger pin and echo pin on the sensor must be connected to the user-defined Arduino Board pins, as defined in the code. In my code, I have defined the echo pin and trigger pin as pins 8 and 9 respectively.
3. Connecting a 9V battery to the Arduino Board
In this step, we will be connecting a 9V battery, which is the power source of the gadget, to the Arduino Board. The positive terminal of the battery will be going to the Vcc pin on the Arduino Board, and the negative terminal will go to the Gnd pin.
4. Fixing the complete model
Voila! The gadget is completed, and the final packaging is entirely up to you. I have packaged all of it into a mobile box, with a chart paper as a covering canopy at the top. After the packaging is done, fix the gadget at a height of six feet(as defined in the code, the gadget subtracts the distance between the sensor and the object from six feet, to obtain the object's original height).
I hope these steps would be helpful in recreating this model; it is a non-touch height detector which can be useful in this Corona Virus crisis, especially in hospitals and such places where height is a requirement to be checked.
Thank you!
EXPANDED TECHNICAL DETAILS
Ultrasonic Geometric Measurement
This project provides a rapid, non-contact way to measure human height with ±1cm accuracy using acoustic reflection.
- Calculated Distance Hub: The Arduino is mounted at a fixed, high point (like the top of a door frame). It uses an HC-SR04 ultrasonic sensor to measure the distance to the ground ($D_{total}$).
- Subtraction Logic: When a person stands under the sensor, it measures the distance to the top of their head ($D_{head}$). The Arduino then performs the simple but effective calculation: $Height = D_{total} - D_{head}$.
User Interface
- Clear Readout Dashboard: The result is displayed in inches or centimeters on a sharp I2C OLED or 16x2 LCD. The code includes an "Auto-Hold" feature that freezes the measurement once the reading stabilizes for 2 seconds.