To run a Raspberry Pi as a data logger, you need to pay special attention to the system time because the clock doesn't have a battery. It's possible to add an RTC module with battery backup, but Raspbian defaults to using NTP because it's cheaper. NTP usually works great, but network or power problems can cause timekeeping problems. To avoid incorrect time after power outages, you can have your data logging service monitor NTP's status and wait to record measurements until the time is stable. Read more...
29 Aug 2017
One of the big challenges with growing food indoors is that plants need a lot of light. I made a PAR flux calculator to help with figuring out how much artificial light is enough.
19 Mar 2017
Once upon a time, I made an app called Part 97 Map which contained several maps of potential interest to amateur radio operators in areas regulated by the FCC. The app's time has come and gone, but the maps live on! You can find them here.
20 Oct 2015
TurtleForth is what I call a dialect of Forth that I implemented for interactively creating technical drawings and geometric designs using turtle graphics. It started as a way to draw the floor plan of a house based on precise measurements, but it turned out to be a fun tool for geometric doodling.
My page with a description of turtleForth, sample code, and an interactive demo is here.
24 Nov 2014
This is an article explaining a general strategy to design and build a a sturdy rotating stage platform. It's intended to help people with some existing knowledge of carpentry and stagecraft to overcome the problems which are specific to revolving stages.
22 Oct 2012