Seeing the guts of devices is a fascination that many hackers share. [Txyz] tore down a 2nd gen Google Nest Hub for all of us to enjoy. The video after the break is well produced and relaxing to watch as various heat shields are removed and debug cables are soldered on.
The main SOC is an Amlogic S905D3G, a 4-core A55-based SoC. The important chips are meticulously documented, and it’s a fascinating look inside a device common in many people’s homes. One chip that’s of note is the BGT60TR13C, otherwise known as Project Soli. It is an 8x10mm chip that uses radar to detect movement with sub-millimeter accuracy. This allows the device to measure your sleep quality or recognize gestures. Luckily for us, [Txyz] has included a datasheet and a block diagram. First, the chip fills a FIFO with data samples. Once full, it will issue an interrupt to the main SoC, which empties the buffer via SPI.
The debug cables allowed him to capture traces of the SPI commands to the BGT60TR13C. [Txyz] focused on decoding the various data blocks and the configuration registers. Unfortunately, only a few registers are documented in the datasheet, and it isn’t apparent what they do.
If a hardware teardown isn’t enough for you, perhaps a software teardown to bypass Secure Boot might sate your interest.
Apparently a Google phone uses the same.
https://techtime.news/2019/10/16/radar/
Does anyone know what solvent he is dispensing from the needle bottle to dissolve those glues?
Probably Isopropyl
I believe acetone can be used for this purpose.
this could damage the plastic… I think is isopropyl
if that’s standard glue, it could be IPA (Isopropyl Alcohol, also known as rubbing alcohol). BigClive uses that a lot on his channel to liberate batteries and dissolve glue to get into some of the things he tears down. It works a treat for all sorts of types of hot melt glue.
Regarding the alcohol, at least in Europe you have to be careful with generic names (??) like rubbing or cleaning alcohol. You can get a bottle with “alcohol” with absolutely *awful* smell and iirc some acetone (that messes with some plastics as said) added to prevent people from drinking it. In doubt buy 99,9% IPA online.
It’s ethanol, and thus great stuff for cleaning, but with a horrible taste added to it to prevent consumption.
A horrible taste that sticks around even after all of the alcohol has evaporated off, leaving you to wonder why that sushi tastes so strange. (Wash your hands, you filthy animal.)
I think it depends on which country you are in, at least according to http://www.distill.com/specs/EU2.html e.g. And according to this link some countries use acetone to denaturate alcohol. Here in my country there is “burning alcohol” that has a so *horrible* smell that i makes me almost sick. I only use IPA for cleaning and stuff, it’s not that expensive and smells way less awful (of course it do have a strong smell, it’s alcohol after all).
Hannah Fry tore down various objects in her series “The Secret Genius Of Modern Life”. One of the most satisfying was when she dropped a bank card into a glass of acetone. The card dissolved away and Fry then fished out the chip and wires that made up the antenna, and it still worked! Can I post a link to a video of that segment? https://vimeo.com/780672803
Although I still like pulling things apart, it has lost so much!
These days pulling apart something is most likely to damage it (broken clips), and all you get is a PCB with a lot of black chips with no legs.
A decade or two ago, it was standard screws (no penta-lobes back then), and a PCB had a plethora of colour to it.
Yeah. Technology has gone far (way to far if it is for making spy devices for/from Google imho), that’s impressive but if you have a broken device it has become really difficult to fix and/or repurpose/reuse components. The joy and the hell of SMD i guess… And i am not even talking about clips and glue.
OTOH, this one is easily separated into its component parts by simply unplugging all the flat-flex, so that’s nice.
Yes, but how many of the components can you repurpose? The main board is probably useless, execept if it’s fully open source (hardware and software) and/or you do A LOT of RE-work (which might be illegal in some countries). And desoldering a single component to reuse it, yes, you can, but everything is small, difficult to identify, probably difficult to get a datasheet for some parts and you may have to do reballing and stuff.
I don’t say SMD is a bad thing, after all we wouldn’t have small and powerful devices without all that stuff, but for hackers it can be a huge pain. Especially those markings ABC where 2 digits/letters are actually a date-code or similar so you can NOT simply search for it online.
Assembly techniques certainly have come a long way! Once the cover is off (and god help you getting it of sometimes – regardless of retaining the ability to put it back on) the circuitry inside is very modular. Everything is plugs, sockets, ribbons. Remember when everything was point-to-point soldered!
I like SMD, even for hobby stuff. 0.5 pitch leaded and 0805 is the sweet spot. BGA and less than 0402 is not on for hobby though! And component marking has indeed become a nightmare. Is that SOT23 a FET, BJT, N, P, dual diode, or maybe even a SSN (silicon serial number)…
The thing that most people are interested is stereo audio out. Can you please tell us or anybody knows if it is possible to put an audio jack for audio output?
Since chromecast audio has been discontinued, there is really not other alternative at this price, so if we can pair a Google Nest Hub with an audio amplifier, it would be the ultimate home audio solution.
I see that the speaker has 3 cables. Can you please investigate if it is by any chance a stereo output source? Or else, are there any points on the PCB that we can extract stereo audio?
Thank you.