CineRat 03 Hardware build Instructions

Frame assembly: See pictures https://www.team-blacksheep.com/products/prod:cinerat_cfhw and https://droneshop.nl/ethix-cinerat-drone

Flight Controller Stack Mounting (from top to bottom)

4x M3x7mm bolts (shortened from 10)
rubber buffers (the ones that came with ESC)
ESC
4x threaded standoffs M3x5mm standing height, 6mm thread
Mateksys Flight Controller
4x threaded standoffs M3x5mm standing height. 4mm thread (shortened from 6mm, then chamfered for easier threading)
Baseplate
4x M3 nuts
3d print raspberry pi mounting bracket
Raspberry Pi Zero 2W
Bottomplate (can be a baseplate, topplate or any plate with some holes for the mounting, just to protect the pi)
4x long M3 bolts that screw the bottom plate and the pi mounting bracket onto the standoffs Front -->

For awareness, we will be mounting the propellers in an "inwards" configuration:

Bottom views: <-- Front

<-- Front

Wiring

NOTE: If possible, wire VCC of a 5V device to 4V5 instead of 5. This way the device is also powered on USB power, and not just on battery. This is a quirk of the Mateksys H7.

ESC

Top view: Front -->

I'm using an Aikon AK32 4-in-1 35A (the closest official documentation in here: https://www.aikon-electronics.com/index.php?id=28).

Both the Mateksys and the Aikon use tiny JST-SH-8Pin connectors to communicate. The Mateksys package or the Aikon package should include a pigtail cable and a few empty JST-SH housings that can be pinned as follows (also see images above):

Aikon AK32 4-in-1 35A 6S	Matek H743 SLIM V3	color	Note
-	G	black
+	Vbat	red	used to power Matek, vbat sensor is on Matek
1	S1	White	Motor 1 BDShot
2	S2	White	Motor 2
3	S3	White	Motor 3
4	S4	White	Motor 4
CR	Curr	Yellow
TE	Rx8	Blue	Low-frequency telemetry. Not configured in software. If you need RX8 for other purposes, do not connect this.

#todo setup in BF, with Current/Voltage scale

SBUS receiver

I'm using the FrSky R-XSR EU LBT ACCESS for most of my builds. You need to update the firmware though, so they work with the EU EdgeTX/OpenTX RCs. You can ask Erik about that, I've never done it myself.

The R-XSR uses a 5-pin Molex Picoblade. They normally ship with a pigtail cable that can just be soldered onto the FC, but these cables can also be assembled from pre-crimpled wires and connector housings at the MAVLAB.

Pinout:

R-XSR	Matek H743 SLIM V3
GND	G (Ground)
+5V	4V5
S.Port	Tx7
SBUS_OUT	Rx6
SBUS_IN	NC (Not Connected)

Raspberry Pi Zero 2W

The RPi has 3 interfaces to the flight controller:

UART to forward optitrack and position setpoints to the Matek
Optional: SWD to wirelessly flash new software and live-debug in VSCode
Optional: USB to wirelessly configure INDIflight via USB and download logs

A ground-station laptop connects to the Raspberry Pi via Wifi.

GPIOs

All of the functions require 6 GPIOs and conveniently these are all in one row. So you can get away with only soldering a 12pin 90degree male header onto the PI, like so (note that this picture only shows 9pins and only the UART connection, but I recommend soldering 12 pins):

You can then either grab a 10 or 12pin Dupont connector housing and crimp AWG 28 wire or just use a solder-type female 10 pin header: Left: DuPont housing, Right: Female pin header. Both are in a box in the rack next to the soldering station at the MAVLab

Left: RPi pinout. Right: Matek.

Raspberry Pi Zero 2W	Matek H743 SLIM V3	Note
5V (Pin 4)	5V	could try 4V5 on the Matek here. I didn't test that
Ground (Pin 6)	G
GPIO 14 (Pin 8)	RX2	Remember that UART RX/TX should be twisted-pair!
GPIO 15 (Pin 10)	TX2	Idem
GPIO 24 (Pin 18)	D (SWD)	Optional, for SWD debug and flash. Solder pads on Matek are on lower left edge, see above.
GPIO 25 (Pin 22)	C (SWD)	Idem

USB (optional)

You can just use a micro-USB to USB-C cable to connect RPi to Matek. They are super bulky though, so I soldered them. Quirks:

USB requires a shielded cable with twisted-pair wiring of D+/D-. Won't work otherwise. I just cut up a USB cable i had laying around.
The USB interface of the Matek seems isolated somehow, so I also wired Ground and Vbus, in addition to the data D+/D-. However, Vbus may not be necessary as I may have messed up something else that made it not work before.
NOTE: if still want to use the USB-C port of the Matek normally to connect to your PC, then you need to either power-down the Raspberry, or remove the connection. On the Raspberry Pi side of the cable, I kept the USB-micro connector for this purpose, but it's bulky...

Backside of the PI

Raspberry Pi Zero 2W	Matek H743 SLIM V3	Color	Note
GND	G	Black
DM	D-	White
DP	D+	Green
5V	Vbus	Red	may not be needed

SD card for blackbox logging (optional)

See list of known-good cards in CineRat -- 02 Parts List and 3D prints.
See warnings and procedures in CineRat -- 04 Software Installation and Setup#Optional -- INDIflight blackbox for logs.

Beeper (optional)

I used an active beeper from Kiwi Electronics (https://www.kiwi-electronics.com/en/grove-piezo-buzzer-active-buzzer-2033), but it's not really the right one. This one would likely have been better (https://www.kiwi-electronics.com/en/piezo-buzzer-active-11258).

Active Buzzer	Matek H743 SLIM V3	Color
Q1 Emitter	Buz-	Yellow
J1 pin 2	5V	Red

GPS and magneto (optional)

See picture below as well

Foxeer M10Q	Matek H743 SLIM V3	Color	Note
SPI CLK	CL1 pad	Green	Magneto. don't think it has to be twisted-pair
SPI Data	DA1 pad	Purple
TX	RX4	Yellow	Definitely twisted pair (top left in picture above)
RX	TX4	White
Ground	G	Black
VCC	4V5	Red

Full wiring picture of Matek