A reliable power source, including an RS485 interface, able to provide enough power for a SBC, a display, and few external devices!
Powercom is a power hat used in conjunction with the rotary-controller board. Providing a reliable power source for the Raspberry Pi and including a RS485 interface chip allowing easy communication with any external RS485 device.
This power hat is able to provide enough power for the SBC, a display, and a few external devices.
The UART to RS485 converter chip is powered by the 3.3v generated by the Raspberry. A few convenient LEDs provide some status information about power supplies and communication activity detected on the RS485 TX line coming from the SBC.
The selected RS485 interface chip is compatible with 3V3 signals (same as the SBC) and it includes circuit protection provided by ESD diodes and a resettable fuse, making it a reliable choice for interfacing with external devices without many extra components.
Powercom can be powered with an AC/DC power supply, making it easy to use with old school transformers (24VAC max recommended) or any DC power supply (10-36V recommended). With the latter, polarity is not relevant, making it harder to make mistakes.
Efficiency and absolute maximum ratings will vary depending on the provided voltage, the selected coil is most efficient when working around 12-18 volts.
When connecting the serial line with long distance wires make sure to properly select a termination resistor in your line and ensure also that proper biasing resistors are placed in order to maximize compatibility with 3rd party serial devices. 330 Ohm resistors are commonly used for line biasing, whereas 120 Ohm are generally used for line termination