Whilst operating on battery, [email protected] generates the supplies required for the Raspberry Pi and [email protected] peripherals from a boost converter. When the remaining battery capacity reaches a predetermined level, the Raspberry Pi can be gracefully shutdown over the Firmata communication channel. The same channel can be used to schedule events, for example to have a host wake up and perform a time-lapse image capture. When the battery voltage reaches a critical level, all circuits are switched off to avoid damage to the battery due to over-discharging.
Charge Control System
When connected to external power, the battery is charged using a constant-current /constant-voltage charge algorithm, with pre-conditioning and charge termination phases.
[email protected] will charge and maintain any single 3.7V LiPo cell attached to the industry standard 2-pin JST-PH connector.
Any cell with a standard JST-PH connector that physically fits your application may also be used, but make sure the polarity is correct before attachment.
If external power is disconnected, Ardhat transitions seamlessly to battery operation, and sends a notification to the Raspberry Pi over the inter-processor communication channel.