How to wire and run an old smartphone without a battery. Intro I have an old Samsung Galaxy S5 that I wanted to use to run my 3D printer. There is a great project called octo4a that runs OctoPrint on Android devices. octo4a Using an old smartphone for OctoPrint is a perfect fit – it has USB OTG support to connect to the printer, WiFi to access the controls and upload models, and a camera to monitor the print progress. The only, yet critical, issue is that the kernel for Galaxy S5 does not...