Green Pass

Want to enter a building during the the pandemic? The green pass will ensure only healthy people enter by checking that everyone has used hand sanitizer and has a normal temperature.

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Inspiration

With the COVID-19 pandemic, it is more important now than ever to ensure the health and safety of the public. In order to enter buildings, most places require customers to use hand sanitizer and pass a temperature check. The "Green Pass" device will automate this process.

What it does

This device will send a signal over WiFi to the front desk of the building to let them know if a person can be let in. A ping sensor and temperature sensor will be used. Hand sanitizer will be placed near the ping sensor. In order for a "green light" to turn on, the ping sensor must detect motion (signifying sanitizer was used), and the temperature sensor will determine if the person has a normal temperature. Should both the sanitizer be used and temperature normal, the person will receive a "green pass." The LED will turn green, and a signal will be sent over wifi to notify the building that the visitor is healthy and is allowed to enter.

The Process and its Challenges

The first step of this project was to create the circuit. We connected the ping sensor and the DHT sensor to the bread-board and Node MCU. The hardest part was figuring out the code to connect the DHT sensor to the Blynk app. Next, it was difficult figuring out the exact parameters that would need to be met

Hardware and Software

Hardware: The circuit consists of a DHT sensor, a ping sensor, a red LED, a green LED, two resistors, a Node MCU, an Arduino UNO, and the Blynk application. The sensors were connected directly to the Node MCU, with the exception of the resistors connected to ground through the Arduino as well as the VCC pin on ping sensor connected to power through Arduino. On the Blynk app, the distance and temperature data are displayed.

Software: The main parts of our code consist of connecting the two sensors to wifi. Once the temperate and distance are printed, the code then uses an if statement. If the distance is between 0 and 11, and the temperature is between 20 and 37 degrees Celsius, then the LED turns green. If any of those statements are not true, then the LED remains Red.

What's next for Green Pass

As a next step, we would consider adding a motor that could attach to the hand sanitizer and automatically dispense it. This would be even more COVID-friendly, as it would limit the amount of people touch the dispenser. Additionally, it would further make sure that people actually used the hand sanitizer, and not just put their hand near it (without taking any).

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