I do a lot of 3D printing as part of my prototyping work. One of the most annoying facets of 3D printing I had was filament jams. A printer will be working fine and then mysteriously starts jamming. And since there are several possible reasons, it can be a pain to troubleshoot. In many cases, since these are only prototype parts, I could have rescued the print had I known about the problem.
There is also the annoying end of filament problem where you keep waiting to use the last bit of filament before changing the spool. This is filament runout.
I looked into solutions, but they generally required changes to the printer firmware or had to be activated each time a print was started. I wanted a better way.
So I developed the JamSentry. It can be made from commercially available parts (except for a small custom circuit board that can be obtained quite cheaply). It can pause the print and/or alert the user when a jam or filament runout is detected. It works on any kind of printer including those with direct drive extruders, bowden extruders, and even multiple extruders. I am releasing the designs to the community for private, educational, and non-profit use.
How it works, parts list, instructions on how to make it, etc. are all available at https://robogardens.com/?p=2220.