Methods, apparatus and articles of manufacture for research data gathering are disclosed. An example apparatus disclosed herein is to detect whether the apparatus is powered by an internal power source or an external power source. The example apparatus is also to, in response to detecting the apparatus is powered by the internal power source, perform first processing on a received audio signal to determine audio data to store in storage of the apparatus. The example apparatus is further to, in response to detecting the apparatus is powered by the external power source, perform second processing on the stored audio data to recover the code, the second processing different from the first processing.