That’s a great code. Thanks!
Do you know how to find out the BLE pin code of the Svensa (new name: pure sense)? It is not displayed anywhere on the device or the chip inside. Reading the uuid does not give any information.
I’ve just checked, it’s not anywhere on the device like the Svara. Instead it’s sent to the app when pairing.
You’ll need a BLE inspector app to read the HEX values. I used GATTBrowser for Android.
Scan for BLE devices, connect to your extractor, mine was listed as “Pure Sense”.
It should present you with a list of services for the device:
Select the one with the matching characteristic ID from the YAML, ending in 569b2.
Read the value as HEX, it should return 00 00 00 00.
Hold the WiFi symbol on the fan until the power LED turns blue.
Read the value again and it should now contain the HEX code of your pin to send as the value in the ESPHome yaml script.
To get the value for a Svara, enter the PIN from the sticker in a Decimal to Hex converter. It will convert the 8 digit number into 3 hex pairs:
Reverse the pairs and add 01 as the last pair.
For example, BC 61 4E would become 4E 61 BC 01.
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Thanks again! I did already read the value in the correct characteristic ID with a similar app, but I didn’t know I had to do that in Bluetooth connect mode.
Thanks @Fillius - I’ve got the boost button working via my ESPHome, but the PAX integration commands are all unintialised? What format do I need to put the PIN in to that? I’m getting a 9-digit code if I convert my hex to decimal using the format A1B2C3D4, is that correct?
I haven’t used the Pax integration in quite a while, I only needed the boost function and I used to do it with a shell script.
To get the 8 digit pin, take your 4 HEX pairs from ESPhome (A1 B2 C3 D4)
- Drop the last pair (should be 01) = A1 B2 C3
- Swap the 1st pair and the 3rd pair = C3 B2 A1
- Convert to decimal (as one 6 digit hex value) = 12825249
It should give you your 8 digit pin.
My last pair is a 03 
I tried doing the switcharoo anyway and although it gave me an 8-digit code, it still didn’t work.
Interestingly, your ESPHome example does work to enable the boost by using all four parts of the hex code in the order they appear in GATTBrowser.
Is this a Svara or a PureSense you’re trying to connect?
If it’s a Svara then can’t you just get the pin from the sticker on the fan assembly?
If it’s a PureSense then it probably won’t work with the Pax Calima integration as the service/characteristic UUIDs are different.
It’s the Pure Sense. I’ve seen a request on the git page so will follow up there add Svensa fan to supported devices · Issue #51 · eriknn/ha-pax_ble · GitHub
Installed and works great! Question; why did you use the RSSI sensor? Does it have a purpose? Doesn’t it use unnecessary capacity of the esp32/atom lite?
Good point, I had forgotten about that. I initially added it to assist in placement. I had previously had difficulty reaching one of the fans from my Home Assistant server and I needed to know the best place to put the Atom Lite.