Charger
The charger is used to charge devices such as robots, drones and tablets. A charger has to be activated by applying a redstone signal to it. The charge speed is based on the applied redstone signal's strength, with a strength of 15 meaning a charge speed of 100%.
Note that this logic can be inversed by hitting the charger with a wrench. In inversed mode, the charger defaults to 100% charge speed, decreasing in charge speed as the strength of the redstone signal increases.
When a tablet is placed in the charger, the first hard drive is also exposed to computers connected to the charger, similar to how floppies in disk drives are. This allows transferring of data between the computer and tablet.