» S

Kisssys Expansion Board

The Kisssys expansion is a small, simple and versatile expansion board for the M4. It has the following functions:

  • 4 PWM lines for ESC´s or servos
  • uSD card reader
  • UART1 port for telemetry, powered from stepup
  • Option to mount Polulu stepup converter, fuse protected

Kisssys Expansion boards can be purchased at Viacopter

Board Assembly

Refer to the PDF assembly sheet for details on component placements.

Make sure to line up the 10 pin 0.05″ headers correctly with the M4 board its beeing assembled for.

Connection diagram:

Power Options

Stepup converter:

The board is designed to take a Polulu step up converter module to allow powering 5V (or 3.3V) peripherals from a 1S lipo. This can be handy for using telemetry modules, FPV gear or receivers that need 5V on 1S based crafts.

3.3V version
5V version
Adjustable version

The module sources power from Vcom+, which is the switched 1S battery supply from M4. It is protected with a 500 mA resetable fuse. (F1)

The module outputs its voltage to the “O” pin on the expansion. This pin then feeds the power pin on the UART connector. If you have a beta board (V1), this is the only way to power the UART port to run a Bluetooth module or other telemetry module.

Supplying 3.3V onto the UART port without using a stepup

This method can only be used on the release (V2) boards. It allows to use the internal 3.3V Buck/boost converter on the V2 boards to power the UART port with 3.3V for something small like a BT module.

!!!You can ONLY do this on a V2 board!!

Solder a small wire from C3 over to the “O” pin like this:

Telemetry Connection

The JST-SH connector provides the UART1 connection from the M4. This is set up for Mavlink telemetry, so all you need to get wireless telemetry on M4 is to connect a 3.3V wireless serial interface.

A popular option is the HC-0x based modules, like this one:

Viacopter BT module 

For really small builds, you can remove the module from the backplane (or buy one without a backplane) to get a very small and light telemetry option.

You can just solder a JST-SH cable to the board itself like this:

Remember to rearrange the JST-SH connector pins to match:

Motor Connections

Motor connections M5 thru M8 is broken out to two 0.1″ pitch headers. Note that there is ONLY the 4 PWM lines and 2 DGND connections available, so if connecting a servo to M5 thru M8, you need to powersupply it from another source.

SD Card Slot additional Info


This page was created on 22-Dec-14 by jussi. Last modified on 29-Mar-15 by kinderkram.