Go to the project BP003 if you want to add a bi-colour LED backlight and a power supply board on the thermometer. In addition, an useful video clip is available there to watch the thermometer in action.
I wanted to build this project because I needed a thermometer in my house, but also, because I wanted to have the occasion to use a LCD display for the first time.
I have always been fascinated by LCDs. Their capability to make numbers, letters and drawings on a glass plate is something magic. Thanks to this project I learnt a bit more about them and I discovered the tricks of the wizardry. Despite this, and even if the LCD displays have become obsolete, I still think they are the result of an amazing technology.
I chose to use the ICL7106 as the driver for the LCD display. This specific IC by Intersil, has also inside an A/D converter necessary to “transform” the analogue signal generated by the temperature transducer into a digital one. For practical reasons, I decided to split the project in two different sections, and then, in two different boards: one for the LCD display and another one for the ICL7106 IC.