Embedded instrumentation usually has analog sensors relating to a physical measurement. This analog signal is converted to a digital signal to be connected to a microprocessor. However most of microprocessors presents a built-in analog to digital converters, some of them do not. In this work, we analyze a digital sensor based on a timer circuit providing a pulse width which is proportional to a physical quantity to be measured. The pulse width is proportional to the resistive and capacitive elements, where one of them is the sensor. The experimental results showed a simple circuit as a Do It Yourself –DIY solution for an unavailability of an AD-Converter on embedded instrumentation applications.