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Exposed terminals would need a lot more than a single transistor. It would need ESD protection and it would change the outer case from being a complete sealed over mold into something that had to seal against two exposed terminals. That’s a big change.

They would also need to ship a separate charger device to go with it, which approaches the complexity of the simple ring product.

These are solvable problems, but it would increase the cost, decrease their margins, or both.

For a niche, low volume product with an unknown market demand I think making the simplest possible version of the product is a good idea to start, but at $99 it’s getting into the range where buyers don’t want to think of it as a disposable item.

The bigger problem is that the 2 year battery life depends on the device being used for only short notes like “Add milk to the grocery list”. The people who expect to use this for taking notes or thinking out loud could exhaust the battery in a couple months.

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> Exposed terminals would need a lot more than a single transistor. It would need ESD protection and it would change the outer case from being a complete sealed over mold into something that had to seal against two exposed terminals. That’s a big change.

This is a solved problem though. Wireless earbuds can do it. We're probably just talking about a TVS diode.

> For a niche, low volume product with an unknown market demand I think making the simplest possible version of the product is a good idea to start, but at $99 it’s getting into the range where buyers don’t want to think of it as a disposable item.

> The bigger problem is that the 2 year battery life depends on the device being used for only short notes like “Add milk to the grocery list”. The people who expect to use this for taking notes or thinking out loud could exhaust the battery in a couple months.

$75 for a use once device that could last as little as a few months under normal usage, or $100 for something that could operate for 5+ years. Knowing whether there is a market is always difficult, but if you do crack a market you typically only get one chance to get people onboard.

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> This is a solved problem though. Wireless earbuds can do it

They’re all solved problems!

That doesn’t change the fact that every additional complication adds cost, complexity, failure points, more warranty returns, and time to market.

Saying it’s just a transistor and a TVS ignores the hard parts like sealing the enclosure and building an entire second device to charge it.

Solvable, but less so for a low volume product with unproven demand. You have to be building a lot of a product to offset the costs of developing it.

> $75 for a use once device that could last as little as a few months under normal usage, or $100 for something that could operate for 5+ years.

The retail price of this device is $99. The $75 is only for the promotional preorder period.

It’s already a $100 product. Adding charging ports and a separate charger is going to be even more expensive unless they start shipping 100,000s of these to build at scale.

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Not only that, the charger thing also implies charging it weekly if not more often. I got a pebble watch because I can wear it for 2 weeks without charging. Would hate to have to charge a ring.
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Also ask any serious Garmin watch user about their charging/data contacts. They start to rot away after 1-2 years of being exposed to sweat.
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I don't think I've ever heard anyone complain about that, and I know a good amount of people who use Garmin watches. My own forerunner is still going strong after 5 (I think) years of use, with multiple runs a week for most of that time.
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I know someone whose garmin watch refused to charge after a few years, not sure if it was caused by sweat. Mine is starting to get wonky after a few years. I keep worrying I'll plug in some time and it will stop. anec-data is not that reliable of course.
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Yeah, that's really not great at all! From their website:

> Wait, it's single use? Yes. We know this sounds a bit odd, but in this particular circumstance we believe it's the best solution to the given set of constraints

I don't want to be too harsh, since it seems like the pebble team are working hard at producing some exciting tech. But intentionally making a single use device is phenomenally irresponsible in today's climate.

I know they say they'll recycle them, but it'd be naive to expect anything other than a tonne of these becoming e-waste.

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I was initially put off by the lack of recharging too, but I've changed my mind a bit.

I think the amount of ewaste is pretty small. My uneducated guess is that it's probably about the same as a musical birthday card. And unlike a singing card that probably gets used a dozen times and thrown away, the Index can be used >10,000 times before it's time to recycle it (assuming it lives up to the specs)

For comparison, check out the rechargable Stream ring. It's bulkier, costs >2x as much (before including subscription... The sub alone costs more than buying an index every 2 years), and needs to be recharged every night. It's sort of in line with Pebbles advantage over other smart watches- doesn't need to sleep on a charger every night

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A phone has 10-20x if not more weight of electronics.

I assume you will use your phone for 20-40 years?

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The ring can record for 12-15 hours before it's empty. I'd guess it's incredibly rare that people throw away their phone before reaching 15h * 20 = 12.5 days of active screen time.
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Constraints include needing to keep component cost low and ensuring that they could sell more hardware in 2 years.
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What do you mean by “today’s climate”?
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The EU just mandated cell phones must have user replaceable batteries by 2027: https://www.cereport.eu/news/european-union/91054

So making this single use is kinda flying into the wind in that regard.

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The EU just backtracked on user replaceable batteries for wearables.

https://appleinsider.com/articles/26/07/14/apple-watch-meta-...

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I was thinking about the combination of:

- Human impact on the environment, which e-waste is a big part of, is causing damage to wildlife, and serious climate change.

- There's huge awareness of and push back against bad hardware practices (often around non-replacable batteries) so they must have at least considered this.

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Western Europe is experiencing a record setting deadly heatwave, for one interpretation.
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Yeah I agree if it was 10 yrs then I would say no need to charge, but apparently it's 2 yrs? In that time frame you could totally recharge it.

I agree losing the charger is actually pretty likely but THAT'S ON ME. For a $75 product, I don't want to consider it a consumable.

So 100% agreed, +$10 add terminals and a special charger.

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> How long does the battery last?

> Roughly 12 to 15 hours of recording. On average, I use it 10-20 times per day to record 3-6 second thoughts. That's up to 2 years of usage.

2 years is optimistic I think. 3-6 second thoughts is not much, most ideas I'm having past TODOs are >15 seconds. Plus this would definitely depend also on how regularly you sync to the app.

Bare in mind, these devices have not yet been used in the wild on people outside of the product creator. Maybe one of the use cases is to note down monologues, or to easily record conversations with clients for later review.

1 month battery life is also highly usable, but there at least should be a way to charge it.

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Why can't they just sell the charger separately? If you lose it you buy a new one.

You could even make it a seperate item - buy one with/without the charger, then in 2 years you decide if you want the charger or an upgrade.

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Seeing the index in action next to an oura I appreciate how much smaller/thinner the index is (or at least how much less it seems to “spread” my fingers apart with of a width of 6.5mm vs 8mm).

It’s effectively a regular ring with a button on it that’s smaller than a typical 1ct engagement ring. The oura by contrast (even the 4) is a chonker compared to “regular” wedding bands. I’ve tried in the past but personally a very thick ring is a non-starter for me. Might just be a personal sensitivity thing. Clearly the oura sells.

From a V1/MVP/founder lens I am sensitive to the value in shipping a product that just works rather than doubling the complexity with a bms, custom charger, wrap around flex pcb, and associated engineering effort to mitigate ignition hazards. Especially when there’s platform risk in seeing if this thing even gets used. There’s no platform risk on the watch side which has comes miles from my first pebble/Alerta that was one day charge and blackberry phone compatible only.

As for the ewaste argument? If the market demands a rechargeable product then that’s the right move. But from a weight perspective? This feels performative. Even pessimistically three-four 5g device that are 0% recyclable will generate less ewaste than a 200g phone with 55% recovery and a 5% recapture rate of obsolete devices thats turn over every 3.5 years. It’s like 10x less and probably in the ballpark of what a hypothetical “rechargeable” index would look like.

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A piezo button would be neat, might be able to generate enough electricity for each use without having to rely on a battery at all. Not sure about the form factor here though.
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Or even a thin-film amorphous silicon solar panel + capacitor.

Assuming most of the weight of that ring is the battery, it appears to be storing around 0.5Wh, so two years of operation should amount to approximately 30uW of power.

It should be possible to squeeze this much from a 0.5mm2 amorphous cell in direct sunlight. Considering the ring is 6.6mm wide at the widest point, they could get orders of magnitude more power even in poor lighting conditions, by just wrapping a thin-film solar panel around the ring.

EDIT:

Or just slap on four of these photodiodes:

https://www.sparkfun.com/miniature-solar-cell-bpw34.html

They're tiny, they're light and even though woefully inefficient, they should do the trick.

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I was thinking also about some kind of coil. Being a ring it should be possible to induce a current, with the chassis as a ground.
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It would be funny if solar panels worked this way. We could just spray paint our homes with them. Free energy!!
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Not sure that would work. Charging is not 100% efficient, and if I remember correctly most batteries need to reach a minimum current to start actual charging. When you're talking micro or pico amps, it barely registers as a signal in most cases.
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Cool, let me know when I can order your ring.
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I’m also baffled that they didn’t do this. If I am buying something that becomes so precious to my workflow then I don’t want a hardware subscription. I also want peace of mind that the company will not be gone, or the product discontinued in a few years.
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Hopefully version two is rechargeable.

This is version one, I'm not particularly worried as I will probably upgrade to version two by the time the battery runs out.

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I dunno. If you need to record your thoughts often enough that you're wearing a smart-ring to do it, then it seems like you're going to burn through the 12 hours of recording time pretty quick.
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Probably. Also, if I/we don't buy version one, there may not be a version two.
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> To provide access to the battery, one of the terminals could be behind a transistor enabled by the micro

So it’s a brick as soon as the battery goes flat?

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yep, you can buy a new one
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IIRC EU markets now mandate the USB-C charger for devices (which is not a bad thing, too many throwaway custom chargers....). Adding the port, the USB-C PD circuitry may take up too much room. I think this approach would require some kind of custom charging cradle (probably usb-c connected..). Is having a custom usb-c adapter to charge a device allowed under the rules?
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I think the "dock" itself could be USB C easily, it would probably also significantly reduce the cost of the dock.

> Adding the port, the USB-C PD circuitry may take up too much room.

You don't need PD circuitry for this. 5V 500mA over USB2 is more than enough. But the actual port and battery charging circuit is a bit ridiculous at this size.

I'm not sure precisely what the EU rules are, but the requirement should really depend on the dimensions/power of the device.

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For these kinds of devices, yes.
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I think it uses a silver oxide battery which is not rechargeable.
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