( Sorry, this ended up as more of a rant than intended, it's directed more towards anyone in this position, in the new era of being nearly always connected, informed, and entertained, and no longer specifically directed at the original poster. And this is enlightened by having spent two very long days on a jury selection panel with well over a hundred other jurors, a few months ago, for a case that was expected to run for four weeks. At the end of the second day, after endless survey questions and then individual questioning by both lawyers - and listening to lots of folks give increasingly fanciful reasons/lies why they couldn't serve - I was "thanked and excused" - by the defense on one of their peremptory challenges. )
If the judge says "turn OFF all electronic devices", do what the judge says.
If you want to want an exemption from that, to leave your smart watch partway on, have the integrity to raise your hand to ask the judge, or bailiff, if what you'd like to do is okay. If they say yes, then great, if they say no, then turn the damn thing off. If you really think it won't be a problem, then have the cajones to stand up and ask.
Don't literally take the law into your own hands and make an unannounced exemption for yourself upon the basis of, "well, I think it's okay and besides nobody will notice", or "well, but it's only jury selection", or some such.
If you step out of line like this, and one of the lawyers picks up on it partway through the trial, you risk causing a mistrial. Unlikely? Sure. But possible. And that could cost the court system tens or hundreds of thousands of dollars, plus lost court time. And it could screw with people's lives. What if you cause a crime victim to have to go through a long and painful testimony and cross examination a second time? What if they just can't go through with it a second time. Yes, jury duty can be boring. It's also your civic duty to do it to the very best of your abilities. The chances of getting caught are moderately low, but the stakes at risk are crazy high. Suck it up and pay attention.