I can only see a couple features missing from this being the absolute perfect induction heater for me in every way (1 software, 1 hardware).
This is my first post on this site so forgive any formatting issues.
I would like to preface this by saying thank you
@Brenyo and the rest of your team for your hard work designing this device. It is extremely well done and you are doing great work! To me the replaceable 18650s really make this a consumer oriented device, its amazing and thank you for doing this. Although there are a few people who were commenting about extended warrantee's etc, personally as long as you have replacement parts available (for custom pieces) or your support is open to user repairs I see no issues with not having a lifetime warrantee. (Personally I love hex screws, specifically 1.5mm hex with a metric thread, instead of Philips for repairs but as long as its screws and not adhesives for opening the device then I have no complaints).
I have read through all the posts on this thread and I do have a few comments to make. First about software, I agree with the comment about an option for relative percentage for the LED indicators. This does make more sense for me since If I set it at 180C I would like it to tell me its ready at 180, however I do have a recommendation for an additional option that would allow for the absolute colours (as planned) and informing the user when they are approaching their
own set temp. Why not change the pulsing speed of the led to indicate how close it is to the set temperature? Slow pulsing when its cold going up until it is very fast (almost strobing) just before its ready and finally solid for at temp. You can keep your colour ranges if you like but using the pulsing speed would allow for even colour blind users to tell when it is at/approaching the temperature it is set at. For combustion warning you can use an SOS pattern flashing in red (or just 3 flash, pause, 3 flash).
For user upgradeable firmware, I believe it is definitely worth the cost for allowing this to be done over the USB C port. Even if you only plan on doing major firmware revisions, having a stable bootloader to protect against bricking is essential. You could always have a switch on the inside on the pcb/under the batteries to allow firmware writing. This can help you in cases of random bugs that get through QC, corrupted firmware, or adding features down the line. (Ofc this opens up the option of adding escribe-esk software for programming in profiles in the future but afaik this will not be needed)
Now for the biggest feature request. Either this would have been done during the pcb design process (and is being kept hush hush), or it will be something that could be considered for a future revision/v2. That is, USB-C PD passthrough. This would allow for battery-less desktop operation (although there is the overhead available to also trickle charge batteries) or using it though a power bank that supports high watt USB-C PD. I realize that you are drawing 70W for heating from the batteries, and I am not sure what voltage you are using for the coils, however would efficiency gains from a 20V input allow for use with a 60W+ power supply (20V @ 3.0A)? This would really be the icing on the cake as you can have an AIO desktop/portable IH that's
tiny.
My last comment is about those people who really wanted a throughhole so they could adjust the depth. I do not see myself needing this feature and I definitely prefer having a bottom so that every hit is consistent, but for those who feel they
need a this I might have a solution. I am not sure how much space the coil takes up however, an option for a future revision would be an adjustable coil. I understand you use the bottom of the hole for temp control (and tbh I do not see myself needing any additional adjustment) so you cant change the physical depth of the device, but why not have a physical slide for the coil? allowing the coil to be moved higher or lower to center the magnetic field on a different area. I realize this is likely not done as the coil would already be taking up the full depth, but incase it is not I thought I would throw this out there.
Again, thank you to Brenyo and the rest of the MAD heaters team for their work on this. Please don't take my comments as negative criticism about your existing designs. You guys have all done amazing work and this is
your baby after all, as long as you are proud of it, you have done your job right.