Temperature and humidity measurements are a nice addition ... He decided to take an in-depth look at the DHT11 sensor; which you can get your hands on for under $3 if you know where to look.

Keyestudio’s Easy Module Shield is a learning platform for those just entering the world of Arduino and doesn’t require any soldering, making it easy to use as well. The add-on board features a DHT11 ...

Thus, the car adds a DHT11 temperature and humidity sensor, along with a BMP280 air pressure sensor using the Grove connectors. Driving the car is done via a Blynk smartphone app that communicates ...