In everyday praxis we often need to demonstrate measuring devices?such as thermometers, manometers
and voltmeters? with large enough displays that they can easily be read from anywhere in the
classroom. In some cases, computers with a measurement interface can be used as a substitute, but
often this is not possible (for example in the lab or in an outdoor environment). We present a
low-cost basis for demonstration devices that can also be used in situ as data loggers or in the
classroom as computer interfaces.