This tutorial will show you how to interface your Arduino to a HTU21D humidity and temperature sensor and start taking measurements. Once you’ve got the basics, we’ll take a look at configuring the sensor to optimise its performance. What you’ll need:
A few days ago, my HTU21D temperature and humidity sensor from Adafruit arrived in the mail. I’m planning to use it for a temperature and humidity display at home.
In one night I managed to start reading temperature and humidity measurements from the sensor using my own code that uses the Arduino Wire library. I wrote my own code instead of using the Adafruit HTU21D library to practice and learn interfacing a micro to an I2C device. All the measurement results are then output to the serial terminal.
Introducing the MicroLogix 1400 PLC (1766L32BXBA) from Allen Bradley.
A PLC – Programmable Logic Controller – is a device that is widely used in industry for controlling electro-mechanical processes. They are a different beast to your Arduino – you don’t get much change from $1500 for this model PLC – being that they are more robust in construction and flexible to program (PLC ladder logic or statement list programming is a different approach than using a language such as C).
This model is considered a ‘shoebox’ PLC due to its size being about the size of a ‘shoebox’. It is by no means the largest or most powerful PLC that you’ll find but it is definately not a slouch for small to medium automation tasks.
A quick rundown on this device’s specifications;
SteelCity Electronics 