[solved] What the hell is this?

[Greybeard]

A few days before the new year I found these electronic parts on the sidewalk. I can see a 3.7V battery and a kind of microphone capsule with 3 connections, and a metal tube that is connected to the rest of the circuit with 2 red connecting wires. I can see an SMD LED on the "microphone capsule" that lights up briefly when the battery is connected (the wire was broken and I soldered it back on). In addition to the battery supply (red and black wires), there is a third connection on the capsule (blue wire) that goes to the mysterious tube. It could be a switching output of the capsule that temporarily supplies power to the "tube component". There is a layer of fibrous material in the metal tube.
I measured a resistance of about 1.5 ohms between the two connections of the tube.

Maybe someone knows what function this could have...

(Sorry for the low quality photos...)

[tunk]

Most likely this: https://en.wikipedia.org/wiki/Electronic_cigarette

[tooki]

Yep, it’s a vape device. The thing that looks like a microphone is a pressure switch. (It certainly looks to me like the vape makers repurposed electret microphone parts to make those switches.)

Bigclive on YouTube has done a number of detailed teardowns of these things.

[RoGeorge]

That's the air inhale sensor from a vape.  A capacitive air sensor with a LED on it.  Looks like an electret microphone bud, but it isn't that.

Many vape devices are single use, though they have a rechargeable Li-Ion cell inside.  Since they are single use vapes, many discard them as if it were cigarette butts.  The battery of a disposable vape does not have any battery management system (BMS) board, so if you want to reuse the Li-Ion cell, buy some BMS for single cell Li-Ion.  Buy the BMS type that look like a small disk PCB with the same diameter as the Li-Ion cell.
 
https://hackaday.com/2022/05/05/2022-hackaday-prize-disposable-vape-pens-turned-project-parts/

[tooki]

Are they capacitive?!? I thought they simply allowed the membrane to make contact.

[CaptDon]

Amazing, single use devices with lithium batteries made so cheap they are throw away. What a waste.

[Haenk]

Amazing, single use devices with lithium batteries made so cheap they are throw away. What a waste.

Considering all the steps our green party (currently part of our dictatorship elected leadership) is taking to prevent any kind of emissions and waste, I find it truly amazing these are not banned yet.
Surely most politicians and manufacturers know these are going to be just thrown away. At whatever place the user is. Containing toxic substances, like nicotine and that lithium cell.

[tooki]

Many of them are rechargeable, it’s not as though all vape devices are disposable. But yeah, I’d be OK with banning disposable ones…

[Zero999]

Are they capacitive?!? I thought they simply allowed the membrane to make contact.

Yes, they are capacitive. I've opened one up before. It has a similar membrane like an electrect microphone, except it contains a specialised IC, which contains a high current output to drive the heater, rather than a simple J-FET.

Here's a link to a data sheet for such an IC.
http://www.txsemi.com/pdf/%E5%AE%9A%E5%88%B6IC/%E7%94%B5%E5%AD%90%E7%83%9F/TX818C_V1.0.pdf

[RoGeorge]

Thanks for the datasheet.

Apparently the same chip is also a BMS and a charger?  That will be great! 
And in the pinout, there is a 'diaphragm microphone probe pin' .  Maybe that capsule looks like an electret microphone because it is one.  Could be, if it senses the hiss from the air inhale passing through.

I'm gonna check if that is true for the disposable type, too.  Might be.  I have one of those single use vape, I've bought it some months ago, for its battery and the Al tube it is in.  The plan was to make either an active probe, an ESR meter, or a short circuit finder, maybe all of them, but never proceeded with that project.

[Bud]

I picked up two of those vapers by the sidewalk, handling with caution, who knows who used them. The batteries after charging measured 500mAh spot on. One had a small PCB with USB-C charging port, ready to be integrated into a project 

[mike449]

Be careful with these batteries. I picked one of these things on the sidewalk and extracted the battery. The capacity and internal resistance were good. I didn't abuse it in any way, but after a couple of cycles it bloated and even leaked. First time I smelled the Li-Ion electrolyte. Luckily it didn't ignite.

[Greybeard]

Thanks for all your replies. 

If it's a single use device, the battery may be a non-rechargeable Lithium-Thionyl Chloride type...

And yes, it's an electric cigarette.

I was googling for pictures of electric cigarettes and found this:

http://robruark.com/other/Teardowns/Vape_ASIC/vape_asic.html

I did not find before, because I was searching "acoustic triggered fireworks igniter" or similar... 

[RoGeorge]

extracted the battery. The capacity and internal resistance were good. I didn't abuse it in any way, but after a couple of cycles it bloated and even leaked.

AFAIK, the raw cell inside a disposable vape has no protection circuit (no BMS).  Did you attached one like these?



Every raw Li-Ion cell has to have a small protection board inside besides (sorry for the typo).  That prevents over-charging and over-discharging of a battery during normal use.  Some are also a short circuit protection, or they integrate a fuse, depending on the model.

Each Li-Ion inside a phone or other Li-Ion powered device has a BMS board embedded in the case of the battery, usually underneath the external contacts for the flat square cells (the protection PCB inside has the shape of a long thin band, of a the same width as the battery), and at one oh the ends for round cells.

[tooki]

If it's a single use device, the battery may be a non-rechargeable Lithium-Thionyl Chloride type...

Nope. Thionyl chloride cells are expensive, and they are optimized for extremely low loads (their high internal resistance prevents high current). E-cigs use lithium ion batteries precisely because of the enormous currents they can provide.

[uli12us]

Afaik the tiny 6pin ic is the bms of the cell. With it, you can charge the cell. But no one knows, how many different ics the producer of the vapes use for their products.

[axmonti]

Just found one of these today on the sidewalk! It was labelled a "Flavour Beast Mode 8000 Disposable", and appeared to still have battery life (and some liquid) in it. I took it home and dutifully took a chisel to the bottom of the case, which allowed me to pull the unit out intact. While I was hammering, the unit turned on, and a sweet smelling smoke started to come out of the unit (blue cherry?), but luckily I had my snips handy and cut the offending wire to the heater.

The 'guts' were the most interesting; here's a partial list of what's on the "motherboard"

• 20-pin 32-bit ARM microprocessor QFP Cortex M0 (PUYA F002AF15-366HP1B - link is similar, but not exact)
• LCD OLED panel (marked P489-A128) that alternates between amount of "juice" remaining and battery charge
• 3.7V 600mAh Li-ion battery (15330) fully charged
• LP4068 Li-ion charger IC
• Condenser mic Capacitive pressure sensor
• Chip under the mic sensor (haven't removed the sensor yet to have a look) not sure: 5-pin DC70 marked as 087Bk1
• USB-C charging port
• Microswitch (on/off slider)
• Various SMD components
• Test points (heater: F1+/-, F2+/-, Battery: B-, B+, +5V)

Pretty incredible for a $30 disposable unit! I've attached a photo; will post more once I remove the mic. It would also be interesting to see what they flashed on the MCU.

[Greybeard]

The "mic" is most probably an air pressure switch...

[axmonti]

The "mic" is most probably an air pressure switch...

Yes! I love that Reddit thread where people don't believe that there's a mic in some vapes; an ARM core with onboard storage, a mic plus a USB-C port - you'd think they added those items specifically for conspiracy theorists...

The mic is located just beside what I think must be an air intake and (as you say) the pressure drop when inhaling turns the unit on. The switch on the bottom selects between regular mode and "Beast Mode", so it's not an "on" switch per se and the unit relies on the mic to activate the heater when inhaling. Likely much cheaper than an SMD air pressure sensor and more reliable than something overtly mechanical.

[RoGeorge]

It is not a microphone, it's a capacitive sensor for air intake.

Looks exactly like an electret microphone, but it is not a microphone.  Watch the videos from the first link posted to see the sensor reused, this one:

or look at the the datasheet links already posted in this thread.

[axmonti]

It is not a microphone, it's a capacitive sensor for air intake.

Looks exactly like an electret microphone, but it is not a microphone.  Watch the videos from the first link posted to see the sensor reused, this one:

or look at the the datasheet links already posted in this thread.

That's exactly it, plus it explains the 5-pin IC under the sensor! Thanks for posting the video; the OLED activates when I touch the IC leads on this unit as well...I just assumed for $29, they were using the cheapest components they could

[soldar]

Big Clive has a look

[RoGeorge]

I've found a Li capacitor in a toy RC car, too.

Lithium capacitors are safe to accidental cut or piercing (when stabbed, they don't burst in smoke or flames, like Li-Ion batteries), but they have both a maximum voltage specs and a MINIMUM voltage, too.  Can't be discharged to 0V.  They require the same handling precautions as Li batteries (during assembling in the final circuit), and a battery management/protection, too.  The sad part is they need to never be discharged to zero volts.  If discharged less than 203V, they get permanently damaged.  They come precharged from the factory, and require same handling precautions as raw Li-Ion cells.

What's worst is Li capacitors self-discharge much faster than Li-Ion batteries, so if you forget a Li capacitor discharged at its minimal voltage, with time it will self-discharge even lower than that, and will become permanently damaged.

[soldar]

I believe they are not capacitors but battery cells.

[Gyro]

Lithium capacitors - that's a new one! No they're just Li-Ion cells, put in a different (quite useful) package as Clive explains.

https://en.wikipedia.org/wiki/Lithium-ion_capacitor