Abstract Measuring cuttings and cavings flow while drilling allows to account the amount of cuttings which are drive out from the annular section of the hole, quantify the volume of collapse in the wellbore and estimate the final well geometry at real time conditions, these information can be used to develop strategies that may help to control wellbore stability while drilling. The design, construction and a field testing of a prototype that can automatically record data while drilling from cavings and cuttings flow to be analyzed in real time is presented in this paper, the prototype is used to identify situations in which cuttings and cavings flows are high enough to cause instability of the drilled well in real time. The system was developed to estimate the actual diameter of the well based on information gathered by it, this can be used to establish a comparison between the ideal diameter and the calculated which will allow identifying zones in which the wellbore failure may occur and figured the approximate size of collapse. This prototype has been used in several wells in Colombia, located at different basins of the country, a study case of a well sited at Middle Magdalena River Valley Basin is presented in this article, the results obtained from the use of this tool are satisfactory and can accelerate the process of decision making and evaluation of the borehole stability while drilling since the responses are given in real time.