Smartphone Without a Battery (2022)
2 days ago
- #Smartphone Hacks
- #DIY Electronics
- #3D Printing
- Using an old Samsung Galaxy S5 for OctoPrint on a 3D printer due to its USB OTG, WiFi, and camera capabilities.
- The smartphone's kernel doesn't support charging while connected to a USB device, leading to the creation of a 'fake battery' circuit.
- The 'fake battery' circuit provides 3.4-4.4V between (+) and (-) terminals and a ~2350ohm resistance for the thermistor (T) terminal.
- A silicon diode is used to drop the 5V USB power supply to ~4.3V, suitable for the smartphone.
- A combination of 2200ohm and 150ohm resistors in series creates the necessary resistance for the thermistor.
- A 1000uF capacitor is added to stabilize power, and Battery Saver mode is enabled to reduce shutdowns under load.
- Camera usage in OctoPrint is minimized or disabled to prevent crashes and excessive power draw.
- The circuit is built on a prototype board, mounted in the battery compartment, and powered via a JST connector.
- The setup has been successfully running a 3D printer for several weeks.
- Notes on diode voltage drop and capacitor usage for improving power supply stability.