
Overview
The Gravity: I2C Oxygen Sensor is based on electrochemical principles and it can measure the ambient O2 concentration accurately and conveniently. With high anti-interference ability, high stablility and high sensitivity, this arduino-compatible oxygen sensor can be widely applied to fields like portable device, air quality monitoring device, and industries, mines, warehouses and other spaces where air is not easy to circulate.
This compact dfrobot oxygen sensor supports I2C output, it can be calibrated in the air, can accurately measure the oxygen concentration in the environmentit. It is compatible with many mainboards like Arduino Uno, esp32, Raspberry Pi and so on. Its effective range is 0~25%Vol, and resolution can reach to 0.15%Vol. It supports wide range input voltage: 3.3V to 5.5V.
Moreover, the lifetime is as long as 2 years. With simple Gravity interface and practical sample code, you can build your own oxygen concentration monitor easily and conveniently.
Get Inspired

Another Slot Car Lap Counter, but if I did it anyone can do!

If you need a device which draws a certain amount of current and power for testing, then GreatScott! has just the solution. His project uses an Arduino Nano, along with a separate IC and a voltage divider, to measure both current and voltage input from the power source. It then employs this data to properly adjust a MOSFET, dissipating the correct amount of voltage and power as required. Interface is handled via a rotary encoder and a 16x2 I2C LCD display, and the electronics are housed in a solid-looking enclosure. As seen in the video below, the adjustable constant load features an impressively large heat sink, needed to take care of the 30V and 20A that the setup is capable of drawing.