For a long time, this section was mostly a place holder. While I was working full-time as a software developer at several Silicon Valley companies, I was also thinking of writing my own software in other areas, although I never seemed to have time to do the extra-curricular development work I was thinking about. Since I retired from full-time work, I haven’t had nearly as much free time as I might have thought I would, either, but I’ve gotten started on several projects. One of these, which has its own Web site (https://hemevision.org), focused on developing an optical imaging cytometer which would be inexpensive, portable, and easy enough to operate that it would be effective in detecting and treating diseases such as HIV/AIDS, malaria, and tuberculosis in resource-poor areas. I have had trouble in finding suitable hardware to serve the analyzer function (essentially, a portable wide-field fluorescence microscope which would be easy to use, rugged, and inexpensive; there are some promising experimental devices being developed, but none yet available for commercial use). Another idea, which has not yet been developed enough to have a Web site describing it, was to develop a portable heart monitor (essentially a Holter monitor) which was inexpensive and rugged enough to use in remote, resource-poor areas, based on the Raspberry Pi single-board computer — early experimental work on this looks promising, but it’s still a long way from working satisfactorily. I have had some success with smaller-scale trial projects, though, which were started as programming exercises to learn how to develop software for cell phones and tablets. One of these was a program to calculate aerobic points for several types of exercises, based on the work of Dr. Kenneth Cooper and his associates, as described in books like Aerobics, which is now available as “AerobiCalc“, an Android app, on the Google and Amazon app stores. It’s free, so feel free to give it a try. I’m also working on another one, which is just about ready for release. It’s an interactive map of Calaveras Big Trees State Park, which I’ve mentioned in some other places on this site. The app, which will also be free when it’s released (soon), will show maps of the park, at various levels of detail, and show the users exactly where they are on the map. Since most parts of the Park have neither cell phone nor wi-fi service, it operates entirely by GPS satellite readings. It should be helpful to Park visitors, so look it up (again, soon, on the Google or Amazon app stores) if you’re planning to be one. Feedback on these apps, as well as any ideas for new ones you’d like to see, is always welcome.