f.u.n.k.e. ATR833 BLE RS232 case

Case for original f.u.n.k.e. ATR833 Sub-D connector (SSATR2) to add BLE serial for Skydemon.
It is designed in a way to sit under the original connector at the back of the radio and not physically block anything else (as it's virtually the same size).
 

Disclaimer
I'm not responsible for any damages and provide below information as is as a copy of what worked for me. Do your own due diligence and ensure you know what you're doing before you play around with your avionics.

Intro

I drilled a 4mm hole in the top half of the Sub-D connector, but you could of course also drill a hole on the side of this case and run the cable through the normal Sub-D cable inlet (mine was already too packed, hence the more direct way).

The case uses the original threads but requires longer screws (M3x20) and has space to fit the DSD Tech HM-10 or HM-18 together with a MAX3232 on a PCB. I also added a PTC PolySwitch with 0.25A on the +5V input side, just to be sure nothing funny happens should there be a short or issue within the BLE case/module.

You ofc need to do some soldering for connecting everything in the case and the PCB within the radio Sub-D casing.

HM-18 config

Changing the name of the module helps identifying it in the cockpit (well at least once you have more than one as they come with the name DSD TECH or similar). I used a USB TTL serial converter and connected it to the module (it can also power it). Opening a terminal (like hterm under Windows) with 9600 baud, N, 8, 1 you can check the name using:
AT+NAME?
and change it using AT+NAME<NEWNAME>

Connection

HM-10/18 +5V → + on RS3232 PCB right side → + on RS3232 PCB left side → PTC PolySwitch 0.25A → radio +5VDC (Pin 24)
HM-10/18 GND → - on RS3232 PCB right side → - on RS3232 PCB left side → radio BATT- (Pin 13, 25)
HM-10/18 TXD → TTL input on RS3232 PCB → RS232 output side on PCB → radio DATA RX (Pin 9)

For orientation: 
The RS3232 PCB I used has the TTL levels on the top right side (the little dot on the chip marks Pin 1), and the RS232 levels on the left top side of the PCB.

Given it's used in a plane, I chose PAHT-CF filament which is phyiscally tough and very temperature stable. I also used some hot glue to fix cables inside the case to avoid any damages through vibration/shaking during turbulences.

BOM list

• 2x M3x20 mm screws (I used V2A ones to avoid corrosion)
• 1x DSD Tech HM-10/18 (I recommend HM-18 due to lower power consumption and Bluetooth 5.0), I ordered mine at amazon.de
• 1x MAX3232 on a PCB, I found mine at androegg.de but they also exist on amazon and ebay
• 1x PTC PolySwitch 0.25A, available on eBay and elsewhere
• a few cm airline specified cable (I used AWG 22 with 3 wires)
• optional: I ordered one of the original f.u.n.k.e. Sub-d connectors, so I could prepare everything prior to the works on the plane panel. Found mine with junkers-profly.de
  The sub-d connector is produced by Conec and seems to be the model 165X17579X which you therefore could also order, should you just be interested in the top half of the case.