A great article that can act as a primer on extracting data from embedded systems, as well as give some  ideas on securing them in the first place. 

From the article:  “During a forensic autopsy an artificial pacemaker was secured for forensic information analysis. An academic hospital was contacted and they had equipment to read the data from this pacemaker via a wireless interface. The extracted information contained around 10 pages of details like name and date of birth of the patient, timestamps of hospital service, technical parameters, and stored measurement details related to the heart function.”
The article is a part of a series of extracts from a useful book called “Handbook of Digital Forensics and Investigation.”
See the excerpts here:  http://www.embeddedinternetdesign.com/showArticle.jhtml?articleID=228300358 (as of 26 March 2018 at 9:18am MDT, this link is broken and has no alternatives).