1. I have a target ROR curve that I got from a previous roast and modified a bit.
2. Integrate this ROR over time and add T0 temp, to get a ET line.
3. Do a reference roast with the desired beans at the same fan speed as the final profile. With this I get the relationship between ET and Ikawa In Temp.
4. Using this reference curve transform integrated ROR (ET) to Ikawa Temperature
5. Sample this curve and transform into an Ikawa profile.
6. Send profile to roaster and test. Get the new ROR.
7. Repeat : Modify profile to adjust until desired ROR is obtained.

• Ikawa Emulator. A linux python program that helps test the app. Emulates an Ikawa, was useful to get started. This is not part of the app and not sure would help much now.
• Mobile App, Communication with the sample roaster ( send profile, log ) The app allows to send custom profiles, log temperatures, state ... The app also reads from the ESP32 PT1000 sensor.
• Realtime view: A simple website for realtime roast visualisation. I got inspired by Decent's visualizer.coffee
• API for Experiment creation and analysis: Here I go with python approach. Using python you can create profiles, and analyse them. So far it allows for creation of profiles, has a few parametric functions to define experiments and on the analysis side it lets you compare different roast parameters of the said experiment.
• Website for Experiment creation and analysis: This one I have just started, and so far it's not much. But the idea is to have the functionalities that the python allows but on a more user friendly website. A place to keep track of all the sample greens, see the profiles, and create new profiles as well as experiment groups.

Philosophical musing: does communicating with the IKAWA via third party apps, void the warranty?

BLEDevice::init("ESP32_PT1000");
#define SERVICE_UUID        "19763624-d8ea-4221-aa30-bbf6f1717140"
#define CHARACTERISTIC_UUID "cb239101-6a43-42c5-8484-db880c08ebab"

temp = int(max_31865.temperature(1000,RREF)*10);
temp = temp & 0xFFFF;
byte frame_end[4]={126,highByte(temp),lowByte(temp),126};
pCharacteristic->setValue(frame_end,4);

• First you'll need to send a profile. You can skip this if you want, but then the visualiser web won't know what were your set points.
• Once the profile is in the IKAWA go to main screen ( the little home , or 1 in the screenshot)
• Press Log PROFILE NAME
• Enter your beans, weight and any comment.
• Press log. At this point if it all went well you should see some text on the CSV state message box. This is a CSV of all data collected, if you press the box it will let you send it as an email ( just developing purposes ).
• If everything is working so far you can perform you roast on the IKAWA, drop the green beans into the chamber, close it, press the button and you should see the graph on the app.
• Once the whole roast is finished and you have your roasted beans press stop.

So, the logging appears pretty specific to ESP32 hardware I'm not familiar with (although I see an Adafruit board is involved). I'm guessing it's open source - can you provide some links to it?

Is the Library in your app created within the app, or is it being pulled off the roaster?

You state the phone must be connected to the internet, but technically, isn't just Bluetooth enough?

which has me suspecting there's some sort of handshake/registration with IKAWA's servers before connecting to the roaster.

Regarding the warranty question:
If I were IKAWA, I'd claim that the factory app has built in all the necessary limits and error traps to keep both the roaster and the owner safe from thermal disasters. Unauthorized third party apps may not be able to provide those same assurances, although I expect/hope that safety is built into the firmware and hardware. Apologies for saying the paranoid part out loud, but I will be careful before messing with a 2KW appliance. I saw the phrase "open source" mentioned, so posting the code for others to review could go a long way to calming concerns. Perhaps the Artisan experts on this forum can offer some advice here.