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Comment by genter | Hacker News Reader

If you already have the fiber in place, that's dirt cheap compared to hiring a sparky to run power for a sensor.

I don't understand how people find 3V at 180mA usable, isn't it like 0.5 watts?

Watt are you using it for, though?

You can use it for a low voltage relay switch for example. Recently got a device that has a small LCD, buttons, a small OS and which consumes ~ 20mA at 4V.

Nowadays you can do a lot of things with 3V and 100mA.

maybe they could power a repeater with it.

(this is a joke btw)

EDIT: wait, what if the repeater was amplifying light going the other direction (coming out) or on a different strand?

then you would have rediscovered the Erbium doped fiber amplifier

While light travels pretty far; it doesn't travel perfectly inside the fiber. So over time you lose all the light.

This can be trivially prevented by have amplifiers (analog) along the long cable so that you boost the signal's light level. However now we introduce another problem where the our nice on-off-on square wave starts to look like a gaussian distribution and as it continues to degrade it becomes hard to determine a 0 from a 1 (or say 00 from 01). So instead of amplifying you have a repeater (digital) that re-transmits the original signal (assuming it can read it correctly).

Why not just plug the amplifiers and repeaters into the grid? They probably do; it's just there isn't a grid underwater.

https://www.synopsys.com/photonic-solutions/product-applicat...

Thats plenty for a temperature sensor, PIR sensor, humidity sensor, door open/close switch, a button, CO2 sensor, etc.

180mA at 3v is plenty for a lot of pretty beefy microcontrollers.

It's a perfectly electrically isolated 0.5 W that doesn't need a bulky transformer. Let's say you have a sensor + tiny computer that you want grounded to a high voltage device. You could use this and side step any questions about insulation and isolation.

That's loads for people who are used to designing electronics to run off a coin cell or small Li-On battery. My current project avoids peaks of more than 60mA.

A capacitor would be useful if you need a spike of higher power. If it's the only or you have you will make it work.

Active power draw (average) of an ESP32-S3 is 78.32 mW. Can do quite a lot with that budget.[1]

I'm not sure I'd use this personally, but there could be some situation where it's useful I guess.

[1] https://esp32s3.com/

I’ve designed and installed bespoke industrial cameras running on batteries because running any kind of electrical cable would require recertification of the entire factory floor.

I’m not convinced this fibre wouldn’t require recertification, but I can guarantee I would’ve spent the time and money to find out if this was an option.

Battery operation and maintenance required SOPs, yearly reviews, and a lot of documentation and training.

Quiescent current was in the picoamps, and operation spiking in the hundreds of milliamps, which a capacitor or two could easily handle.

And if this provides communication as well…

An average AA battery will have 3-4 Watt-hours of capacity.

This 3V at 180mA is 13 Watt-hours in a day.

So think of it like consuming about 4 x AA batteries every day, or almost 1500 x AA batteries jn a year.

You can do a lot with that amount of energy. You won’t be powering a switch or computer, but it’s orders of magnitude more power than small battery operated devices can use.

A few lemons/potatoes can power an MCU. 0.5 watts is luxurious.

https://youtube.com/shorts/qLTEtXY5-BQ

especially if the sparky has to scuba dive to install it

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