Show HN: F32 – An Extremely Small ESP32 Board

166 points by pegor a day ago

As part of a little research and also some fun I decided to try my hand at seeing how small of an ESP32 board I can make with functioning WiFi.

jacquesm - 4 hours ago

If you add another GPIO and make a silicone mold you could make an in-cable eavesdropper on USB connections that streams out the data via the wifi. That would be a pretty scary tool in the right circumstances.

atemerev - 4 hours ago

These cables can be bought for like $200 mostly legally.

stavros - an hour ago

This is great, well done! I don't know where I'd use this, but I'd definitely want to use it.

tmpfs - a day ago

This is a very cool experiment, even if the board doesn't end up being that practical (the antenna hack is going to be an ongoing issue I think) your documentation looks great at a glance!

pegor - a day ago

Thank you! I agree, antenna definitely needs some improvement.

Rebelgecko - 3 hours ago

Really cool. I just ran into a situation where it would be handy to have a small Bluetooth device that plugs into USB-C. However soldering something like this seems a bit beyond me, is there a more turnkey solution?

dotancohen - 15 minutes ago

The company that printed the PCB, PCBWay, also offers PCBAs. They're really not expensive, though you might need to order in batches of multiples of five.

anyg - 17 hours ago

If it is a little bigger to incorporate a bigger chip antenna and some GPIO pins, it is going to be very useful for a lot of IoT projects!!

margalabargala - 5 hours ago

The XIAO series of ESP32s is exactly that.
They are 4x the size though, almost exactly double in both length and width.
https://wiki.seeedstudio.com/XIAO_ESP32C3_Getting_Started/
- dotancohen - 13 minutes ago
  
  It's also got 15 times as many GPIO pins as the board in the fine article.
  And this PCBA will be smaller than the battery in most applications anyway.
  - margalabargala - 6 minutes ago
    
    It only has 14 pins, 3 of which are 5v, 3.3v, and ground, so slight exaggeration :-) point taken though
- sho_hn - an hour ago
  
  These are quite lovely. Ceramic SMD antennas are awesome.
pegor - 7 hours ago

Definitely would be more functional with more of the GPIOs exposed.
- forsalebypwner - 5 hours ago
  
  If you want an ESP32 dev board with GPIOs exposed there are dozens (or hundreds, maybe thousands) of other options out there. It makes sense not to expose them when you're going for the smallest possible footprint.
PunchyHamster - 6 hours ago

there is plenty of those already and not all too hard to make yourself, see LilyGo T01-C3
Its of format of original ESP8 so you get serial + 3 IO pins

ingen0s - 5 hours ago

Nice work, kudos!

puzzlingcaptcha - 3 hours ago

01005? Oh no no no. I can barely do 0402s by hand and those are _2.5x_ larger.

joemi - 2 minutes ago

Wouldn't 0402 be 4x larger (if comparing lengths) or 16x larger (if comparing areas), not 2.5x?
sho_hn - 2 hours ago

With one of those mini-hotplates for reflow soldering and a LCD microscope it's still fairly doable.
VTimofeenko - 3 hours ago

FWIW, there's a step by step soldering guide in the readme:
https://github.com/PegorK/f32#building-the-f32
It looks doable, but of course a lot of carefulling is required when placing the components.

Gys - 4 hours ago

> PCBWay does also offer assembly services

Seriously? For a tiny board like this also? Genuine question.

kube-system - 4 hours ago

yes, but they use a machine, they don't do it by hand.

NuclearPM - 16 hours ago

> This can be seen in my highly necessary depiction below.

I love this. Fun and insightful article. Thank you.

pegor - 7 hours ago

Thanks for checking it out!

jason-richar15 - 6 hours ago

[flagged]

lawlessone - 6 hours ago

bot

Will-Reppeto - 5 hours ago

[flagged]