After watching your initial build video, I embarked down the path of building several iSpindel's. I did a lot of reading figuring out the calibration. I finally ended up here:
https://github.com/universam1/iSpindel/blob/master/docs/Calibration_en.md and ended up using the Easy method
In all of that reading I don't recall seeing anything stating that you had to perform the offset calibration. After performing the Easy Calibration the devices seem to read fine. I ran one through a fermentation with Fermentrack over the last 2 weeks. the iSpindel read correct within a point or two through the entire fermentation.
The iSpindel documentation is a mess. There are bits and pieces everywhere. I could have easily missed the page that stated the offset calibration was required. If I did miss that, can you point me in the direction where that is stated?
Thanks!
Howdy,
I've been piecing things together as well. As I understand it, there are 3 calibrations required and an optional one around battery voltage. As far the pointing to documentation to support it, I don't know if I will be able to find it ha ha.
The first calibration is the offset one that's in the video. It simply tells the iSpindel what being completely horizontal is. I don't have any supporting docs to point to for this one but someone on Reddit said that it was required, that they missed it, and that there wasn't any documentation for it, lol.
The second is getting to 25 degrees (+- 5 degrees) in water. I found mentions of this in posts on GitHub saying it's mandatory and recently found it in the FAQ.
https://github.com/universam1/iSpindel/blob/master/docs/FAQ-en.md
The third and final calibration is the page you linked to.
It would be nice if all calibration steps were in one spot, I'm sure the iSpindel community will get there one day.
Another calibration is the battery voltage which I'll cover in a video eventually. It's about taking a multimeter reading and adjusting a number on the config page until they tie in together. There's a formula I found that explains the calculation the iSpindel does but I can't find it this very second.
Another thing I'll be doing is adding temp correction to the iSpindel formula. I have it all worked out in a spreadsheet already. The TEMP variable is available just the same as the TILT variable.
What happens if you miss the first or second calibrations? I'm not sure, but I'm sure there's a reason those calibrations exist. I have seen people say multiple times that if you can't get close the 25 degrees in pure water your readings will be off no matter what you do. I've ran into this issue and have some prototype PCBs I made that I'll be doing a video on soon. My PCBs have a movable battery holder allowing you to move the battery up/down until 25 degrees is achieved.
I actually ran through a full calibration with the easy method and with a real-world fermentation but my firmware had a bug in it, I kept losing my offset calibration, and the values never made sense. I have now fixed my offset calibration, discovered the thing about 25 degrees in water (which I missed the first time), and I will eventually get to the final calibration (again).
I've been confused and I've had to do things multiple times. I spend a large portion of yesterday trying to figure out why one iSpindels' offset calibration didn't save after it was powered off. Turns out you have to press save in the configuration page to create the config file before you can permanently save offset calibration data. You don't get any error on the UI, but errors are firing off in the Arduino serial monitor saying corrupt config file. I am confident the documentation and software will get better but it will be a slow burn. People are donating their time and I'm sure everyone has a day job and a life outside of the internet.
All that being said, if your iSpindel is within a point or two of your hydrometer that sounds pretty good to me. You may not want to open a can of worms and start playing around with it if you are happy with its performance.
If I can help out in any way let me know. I'm sure together we can figure everything out and document the crap out of the iSpindel. I will eventually have a dedicated page on
https://www.OpenSourceDistilling.com tieing all things together.
Cheers!
Joey Joe Joe Jr
