I just finished the first batch of 10 Rachel, equipped with M4, ESC32 v3, Hacker A20-26M EVO and two Emcotec-Boards.
The Power board comes with
- soft-power-function (onboard pushbutton and connector for external push button)
- power- and CAN-distribution for up to 8 ESCs
- 5V 5A power supply (for powering an Odroid device)
- current metering (up to 50A)
- 2-6S batteries
- safety function for discharged batteries: board doesn't power on if cell voltage is <3.4V
The communication board comes with
- UART with level shifter
- Wifi device, connected to RX port of the M4
- LED controller with 4 LED connectors (probably just to indicate orientation )
- buzzer
- SD cardslot
- all pins from J1 and J2 routed to pin headers, some of them have solder jumpers (i.e. J2-6 to buzzer)
- power supply for 3V3, 5V and battery voltage
All pins are protected against reverse polarity, including the battery connector. Probably Emcotec decided for that because students will work with these copters
My personal sample here comes with an additional board carrying the Jeti receiver and an Arduino for converting mavlink to Jeti telemetry. The University will use the onboard CYRF.