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RotaryCell: Making an unmodified rotary phone work over LTE with an ESP32-S3

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Re: RotaryCell: Making an unmodified rotary phone work over LTE with an ESP32-S3

#41

Post by nickff »

alnwlsn wrote: post #33
ralferoo wrote: post #14

Accepting 5V over the RJ-11 jack seems asking for trouble. Someone is going to plug it into a regular phone socket at some point, so it needs to be capable of surviving at least 60VAC. Even if a secondary pair is used, there are so many different wiring standards in use, it'll end up plugged into something live sooner or later.

Luckily telephone lines are very current limited. You'd be hard pressed to draw more than 100mA even with a dead short at ring voltages. One zener diode might be all you need. Also not the most unusual thing I've seen over a RJ11, which includes keyboards, RS-232, other random digital IO and full USB with data. But these are normally on items that are not phones.

>"One zener diode might be all you need."

It would... if you're willing to just let the thing draw up to 0.1W all the time, and fail catastrophically if anything goes wrong with the zener or the supply is more capable than you anticipated (i.e. you plugged into a PoE jack by accident). This is a very bad idea.

Re: RotaryCell: Making an unmodified rotary phone work over LTE with an ESP32-S3

#42

Post by ramses0 »

ge96 wrote: post #31

That would be funny you're at a club with this phone and doing phone calls

Fashion bag. Dock your cell-phone inside, bluetooth pair to the purse (w/ functional receiver + off-hook sensor) and treat that as a siri-enabled headset in a phone w/ fabric coiled cord.

"Ring ring! Hello? Hey Siri, what's the weather and call my ex so I can hang up on them!"

Re: RotaryCell: Making an unmodified rotary phone work over LTE with an ESP32-S3

#43

Post by richdrich »

This is very neat.

An uglier way to do it is with an off the shelf pulse to tone box and a router with VoIP support, like an N300.

Do you think it could use WiFi calling? I suspect that can't be done is it requires one of a limited set of carrier approved phones in each area.

Re: RotaryCell: Making an unmodified rotary phone work over LTE with an ESP32-S3

#44

Post by mikeweiss »

ChrisMarshallNY wrote: post #36
mikeweiss wrote: post #18

Earlier quoted context omitted.

Dunno about you but I don't know anyone with live RJ-11 jacks in their house anymore.

I have one. It comes from my cable modem. We still have a landline. It's part of the cable package, but it mostly just gets robocalls.

Didn't know people still had cable packages!

Re: RotaryCell: Making an unmodified rotary phone work over LTE with an ESP32-S3

#45

Post by K0balt »

c22 wrote: post #32
K0balt wrote: post #21

Earlier quoted context omitted.

If you’re getting into bigger (kg+) drones, it starts to make sense to shoot for 100cycle+ (and for 10kg+, 1000 cycle-ish) lifespans. The economics and the physics work out. But for very tiny systems like the single cell drone featured, the equation starts to favor squeezing every last drop of energy reasonably possible, which means that you can easily get caught out downwind or “stayed to get a few too many pictures…

> ...like the single cell drone featured... Featured where?

Oh that’s hilarious.

I got this article conflated with another I was reading. My apologies to all.

Re: RotaryCell: Making an unmodified rotary phone work over LTE with an ESP32-S3

#46

Post by K0balt »

walrus01 wrote: post #17
K0balt wrote: post #16

Earlier quoted context omitted.

Mmmmmmmmmmhhh. Maybe better to damage A battery than to have a drone fall out of the sky? Also most protected cells have modest current capabilities, and might not be enough for many drone applications. By its nature, MUAVs tend to push batteries to their limits and lifecycles tend to be limited. A battery that does mission X must have a maximum weight and a minimum capacity, and a minimum current spec. If you increa…

So I was referring specifically to this phone hardware project and to flashlights, which don't fly... But my thoughts on drones are also that it's very different if you're building consumer class things that are meant to be re-used or what's going on in ukraine right now. They're using high amp rate cylidrical 18650 and 21700 cells in 6S2P and 6S3P packs for one way trip munition drones where you don't particularly c…

Oh that’s hilarious.

I got this article conflated with another I was reading. My apologies to all.

Re: RotaryCell: Making an unmodified rotary phone work over LTE with an ESP32-S3

#47

Post by K0balt »

aftbit wrote: post #30
K0balt wrote: post #16

Earlier quoted context omitted.

Mmmmmmmmmmhhh. Maybe better to damage A battery than to have a drone fall out of the sky? Also most protected cells have modest current capabilities, and might not be enough for many drone applications. By its nature, MUAVs tend to push batteries to their limits and lifecycles tend to be limited. A battery that does mission X must have a maximum weight and a minimum capacity, and a minimum current spec. If you increa…

Who mentioned drones? This is for a phone.

Oh that’s hilarious.

I got this article conflated with another I was reading. My apologies to all.

Re: RotaryCell: Making an unmodified rotary phone work over LTE with an ESP32-S3

#48

Post by K0balt »

ssl-3 wrote: post #26
K0balt wrote: post #16

Earlier quoted context omitted.

Mmmmmmmmmmhhh. Maybe better to damage A battery than to have a drone fall out of the sky? Also most protected cells have modest current capabilities, and might not be enough for many drone applications. By its nature, MUAVs tend to push batteries to their limits and lifecycles tend to be limited. A battery that does mission X must have a maximum weight and a minimum capacity, and a minimum current spec. If you increa…

What are the chances of this telephone falling out of the sky due to battery failure?

I was going to say pretty low but then I realized you weren’t just be ing snarky lol

I got this article conflated with another I was reading. My apologies to all.

Still, if you don’t want your phone to fall out of the sky, Put it on a drone with proper battery limit discipline.

Re: RotaryCell: Making an unmodified rotary phone work over LTE with an ESP32-S3

#49

Post by ChrisMarshallNY »

mikeweiss wrote: post #44
ChrisMarshallNY wrote: post #36

Earlier quoted context omitted.

I have one. It comes from my cable modem. We still have a landline. It's part of the cable package, but it mostly just gets robocalls.

Didn't know people still had cable packages!

Eh. My wife still watches live TV. I don't. If it were just me, I'd be Internet-only.

Re: RotaryCell: Making an unmodified rotary phone work over LTE with an ESP32-S3

#50

Post by K0balt »

K0balt wrote: post #21
walrus01 wrote: post #17

Earlier quoted context omitted.

So I was referring specifically to this phone hardware project and to flashlights, which don't fly... But my thoughts on drones are also that it's very different if you're building consumer class things that are meant to be re-used or what's going on in ukraine right now. They're using high amp rate cylidrical 18650 and 21700 cells in 6S2P and 6S3P packs for one way trip munition drones where you don't particularly c…

If you’re getting into bigger (kg+) drones, it starts to make sense to shoot for 100cycle+ (and for 10kg+, 1000 cycle-ish) lifespans. The economics and the physics work out. But for very tiny systems like the single cell drone featured, the equation starts to favor squeezing every last drop of energy reasonably possible, which means that you can easily get caught out downwind or “stayed to get a few too many pictures…

Age is a hell of a drug. My apologies, wrong article.
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