Garmin solar charging
 

I would love to never get a sunburn again, but that doesn't seem likely. The next time I get one, I feel like I should be able to use the solar feature to see how many lux hours of exposure it took, and then stay below that in the future. That also sounds too simple, so I feel like I've got to be missing something. Any thoughts?

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I don't get sun evenly on all the parts of my body. So not sure how you'd even begin to use it.

For riding since I use sun sleeves and half fingered gloves, the only place I'm getting sun enough to be a problem is the few inches between the bottom of my shorts and knee on the front side and the top back portion of my calf.

New feature of the new watch or new feature they've made available in the recent update and other watches and devices can show that?

Maybe it's been there longer, but after the update a week or so ago, I've noticed that the Garmin App on my phone now shows Total Strokes. I sort of take that to be how many times the crank turned since I have cadence. Which is sort of interesting as to some extent if compared to others might show whether one is pushing big gears or smaller gears than the other person.

:wtf:does this have to do with the question at hand?

Well, it goes along with my question to you if the lux reading was a feature of the new watch only or was it a feature that was introduced with the recent update and some of the other recent but maybe a few years old watches and devices can now show also show that.

I suppose it was a unnecessarily long example of one of the other new things that I've noticed with the recent device and app updates, but since this is a public conversation, I won't hold to any rational that all conversation must be only and specifically about the question ask.

I'm trying to figure something specific out. It has nothing to do with how old this feature is. That's a bizarre question and it's also not a straightforward one. If you want to learn the history of Garmin watches, start a different thread and I'll contribute, but this one is about helping me understand whether I can use this a specific way. Maybe you'll have more to contribute when you're sober.

Well it also bizarre that you'd derail your thread by arguing whether something is relevant or not. Seems like that will only scare others away from your thread.

I haven't had any drugs, beer or alcohol of any sort in the last week. Though I am about to bottle some home brew beer.

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Can the solar panels collect all the energy that lands on them? I guess the Garmin can only tell me what the sensors collect, it can't measure what it can't see, like a measuring cup that overflows. If not, the amount of sun I'm getting could be more than it says, by an unknown amount.

I spent some time fooling with solar panels for charging reasons and what I found was that the angle of the panel to the sun has an enormous impact on the power output. I would guess that the power output is pretty much correlated to the strength of the sun that the panel is seeing.

But taking that for what's worth, then you might be able to use that as a figure of merit if the lux was constant with time (bad assumption) as to how much sun your skin is seeing - should be fairly accurate for the skin at your wrist since that is going to be oriented to the sun at the same angle as the solar panel in the watch. Unfortunately, if I understand Lux correctly and how sunburn works you'd pretty much have to integrate the lux number over time to come up with a (forgetting units for the time being) total photons or total energy that hits your skin. For example, if you were getting 300 lux for one second, you'd not get a burn. But if you did that for an hour, then probably much more likely.

Then with the lux number, I'm guessing that it's going to change radically as you move your wrist - again arguing for the need to integrate the data to get to an exposure over time number. Will it give you an "average lux" or something like that?

It's great until the EULA you didn't read lets your device manufacturer sell your deliberate sun exposure data to your health insurance company and you need to pay for the mole resection yourself.

Bullfrog Gel sunscreen is less expensive than the solar panels and more effective at preventing sunburn, FWIW.

not so in the OP’s case. He already has the watch that measured sunlight lux which means no additional cost. Hence the question.

Point I was making is that this is a Rube Goldberg operation. You want to prevent sunburn? Ignore dermatologists' recommendations to put on sunscreen if you're going to be out in the sun for more than 15 minutes. No, no, no! Rather, mount a solar panel to your bike. Hook the solar panel up to your (partially discharged) cell phone or GPS. Figure out how long it takes to "get a sunburn" (15 minute rule need not apply, never mind that the most painful effects of a sunburn typically present some time after the exposure ends). Now find or write an app for whatever electronic device you're using that will figure out the battery level change that occurs "when you get a sunburn." Now at this point you could simply set off an alarm, but that's not the Rube Goldberg way. Too simple! Since you might be riding in a bike lane next to a noisy road, or maybe even on that road, when that happens, you need a sure-fire way to get the cyclist's attention. So you want a way to hold a ping-pong ball securely in headwinds or crosswinds, and when the battery is charged sufficiently, launch it at the cyclist's forehead to make sure he gets the notice that he's about to get a sunburn.

Presumably, the cyclist would then pull off and put on some sunscreen. :D

If you don't understand, that's ok. There are plenty of other threads for you.

Oh, I'm wrong? You're not going to put sunscreen on when your "too much sun" alarm goes off??

I think he’s politely asking you to stay in topic or move on. We all get it - you love sunscreen and think this is stupid.

Is it really that hard for people to understand that a person in Seattle would want to enjoy as much sun as possible without getting burned?

UV penetrates clouds, but probably not the watch glass cover. The watch solar charger uses less energetic visible light; it will charge it up under an indoor light bulb. So it really won't work as a good proxy for UV solar exposure.

I use this EPA site: Link to Seattle version

Here, it is easiest just to avoid peak UV (between 11 am and 3 pm) if possible. I use long-sleeve jerseys and other physical blocks whenever possible.

I think the points people have raised about the variability of wrist position and angle with respect to incident sunlight are valid concerns. It might work better if the watch was on one of those handlebar mounts, but it probably would be more useful as an indication of total solar exposure.

The problem with photons is that there is no safe limit for exposure. One single UV photon is enough to dimerize two adjacent Thymines in your DNA, and if it hits the right ones, could cause a cancer-inducing mutation. So increased flux/lux/whatever is simply increasing the probability of a transforming event. There is no safe threshold below which you don't have to worry.

I always wear bike gloves, but had a skin cancer on my hand removed 10 years ago.

Is it really that hard for a person in Seattle to understand that even if you do skewer that windmill you're tilting at and get a notification that you've been in the sun long enough, you need to plan for what you're going to do after that notification? And that if it's more than "stop going around the block and go inside" it's probably going to be whatever you were trying to avoid in the first place, whether it's sunscreen, sun block, sun sleeves and Da Brim, or whatever?

Well, the idea (if I understood it correctly) is essentially to use the watch to help avoid a sunburn. That seems like a good thing, and I've messed around with different ideas for UV detection (it is bad here in the summer), including a solution of thymine in a quartz capillary mounted on a helmet or handlebars, but the problems are (a) you have to do some analytical chemistry afterwords to get a result that might not have any real meaning, and (b) to get it to work, you have to freeze thymine from solution into an ice matrix. If you could just have a piece of radiation-sensitive paper that changed color with UV exposure, that would be ideal (especially if it changes color before your skin does). The watch seems like a great idea, and it might be some variation of this could work.

I'm sure the "viewing angle problem" is a complication, but I'm also sure I can figure out how to deal with it (assuming the idea is workable overall).

A bigger issue is I'm sure the sunburn exposure limit of my skin doesn't reset at midnight, but I can make that work too.

Okay, let’s keep replies on topic. The OP asked a question that’s important to him and looking for meaningful replies. Thanks

Someone was asking similar questions on the garmin forums, that wasn't OP was it?

I suspect you could use the lux reading to do this, but I feel like the correlation would be inexact. So would make sense to use a safety factor. I propose a factor of 2.

I'm pretty sure that if I get skin cancer, it's going to be because of my forearms. The worst sunburn I have ever had was on the back of my hands, I even got blisters. So if someone rides a bike like I do, the watch is likely to be at a very good angle.

​​​​​​It wasn't, to be honest I had forgotten Garmin has its own forums. Thanks for letting me know this exists, I'm sure google can help me find it, maybe there are useful answers.

I've been wearing UPF 50+ clothing for a few years and it definitely works. If I ever find very light weight UPF glove liners I'll send you a PM.

I can see that the viewing angle has a big impact, like on a laptop display.

So far it seems like that won't be a problem. I think that will average out.

New sun hoody arrived today, of course the goal is to only wear it when it's truly needed. 🙂 The cat has claimed the box it shipped in, so everyone is happy.

The watch arrived 10 days ago. I haven't charged it yet. Has 35% left in the battery, it arrived with Annie 80 or 85% charge. I'm impressed.

wow, that’s impressive battery life! Is that including workouts or just as a
smartwatch? Mine gets here on Tuesday.

the angle is pretty much the whole enchilada. I’d have to go figure it out again, but it basically follows the cosine of the angle, if I recall. That means there’s a significant discount in the amount reported compare to skin that’s directly perpendicular to the light. So what you see on your wrist with the watch is not ever going to be representative of what your neck is seeing.

then there is the trade off from sunlight exposure for Vitamin D. What it gets down to, as my wife says, “Health is the slowest possible rate at which you die.” On that happy note….