It is an unusually cheap system, and OP clearly did some thorough research on finding a really well integrated SoC that is available for super low piece part prices. I'd guess Allwinner targets that part at some ultra high volume application and some AliExpress sellers managed to capture some trays of excess parts to sell individually. I wouldn't be surprised if the unit price there is lower than what Allwinner quotes for volume.
And this one of the dangers of basing your supply chain on AliExpress. I've had to caution clients that just because they found some normally expensive component dirt cheap on Amazon or AliExpress, doesn't mean that they'll still be available in 6 months when you need 1000 more.
Base your BOM on a manufacturer-approved supplier. If you can find the same parts for less elsewhere (assuming they're not counterfeit), go for it.
It’s QFN though so you need a reflow oven to make the boards at home.
I’ve had bad experiences with the allwinner chips (the boards I had years ago were very unstable) but the mainline kernel support is very exciting. That you can order a few phones built around them now too is just awesome.
The one that blew me away was the JW5211 switching regulator. I thought he was being a bit extravagant by not just using a cheap linear regulator...but that buck regulator costs 4.5 cents.
Guess I'm a little behind the times. Sure, throw three of them on the board at that price.
Only other surprise was the MOSFET labeled "Q_NMOS_GSD" for the status/power LED. At first glance, with the pull-up resistor, it looks like the FET does nothing. Then I located the reference net (a flag would have helped) on pin 13, so you can turn on/off the LED with the processor, or (depending on initial state of that pin) it will power up with the LED on and turn off only after the processor boots. Neat!
