It's a family of microcontrollers by Espressif. A microcontroller (MCU) is a type of integrated circuit (IC: physical appearance: Black rectangle of epoxy with exposed metal tabs). It has, in the same IC, a CPU, RAM, non-volatile FLASH memory, and a collection of peripherals which vary depending on the MCU. These usually include I/O protocols, ADCs, DACs, DMA controllers, math processors etc.

Stated another way: An MCU, like the ESP32, is a tiny computer, sans the hardware you physically interface with it.

The computing power, and memory is much lower than your desktop or laptop PC (or mobile phone), but if you are using it to run a dedicated task, instead of using a big OS like Linux or Windows, it can complete the tasks really fast (often microseconds) and with minimal power use. This is because it's easy to program to do exactly what you need, with nothing competing for the hardware.

A note on ESP in particular compared to other MCUs: It's one of the only (Or was?) options which has Wi-Fi integrated into the MCU itself. It's a good default if you want that.

They're all just single board computers, generally low-powered (literally and in the sense of capability, particularly memory)

They're generally intended to run flashed firmware and be single-purpose. They usually come bundled with peripheral components and typically have breakouts to add more (pots, sensors, etc).

They're great for doing one thing (though some support firmware switching), and you can build the 'software' for them pretty easily using Python or C-like variants.

So for hobbyists they're perfect. You want a quick LED christmas display you can toggle between Rudolph and Santa from a quick network call? You want a humidity sensor in your bedroom? You want to create a networked security camera? These are the types of use cases for MCUs.

Originally it was the more capable successor to ESP8266, the super cheap chip containing a high speed core with wifi and an IP stack. At one point it powered a huge chunk of all smart devices on the market. Then the original ESP32 was introduced as the successor, with BLE and two cores which were even faster. That made it a very capable chip for tasks demanding compute. After the original ESP32 they decided to add variety and make a whole "ESP32 family" and yes there's quite a lot of variety these days. Even the ISA and cores changed.

ESP32 boards are small and cheap adapters between Wifi (network APIs) and I/O pins for small electronics like LEDs and relays.

If you want a web API for something in the physical world, make ESP32 do it.

"ESP32" is a brand name. It covers devices with different CPU cores - Tensilica Xtensa and more recently RISC-V.

Each type of device has different capabilities. Most have Wifi, some don't. Some have extra RAM and ROM, and some don't.

The main thing that ties all the different devices together is the ESP-IDF software stack.

At its core those all ESP32 are microcontrollers with RISC-V cores[0] and integrated wifi. There's a plethora of peripheral configurations, hence all those ESP32-* variations. This one even has Gbit ethernet and audio, bit still, at it's core (hah), RISC-V with only a few hundred MHz and 512kB RAM. So the peripherals are now similar to a Raspberry Pi, but not the CPU part itself.

[0] older versions had Xtensa cores, not RISC-V.

I have an ESP32 here, it can do wifi, but only like 2 requests per second or so, with 50kB of data (I didn't measure it, but that's approximately what it can do).

I use an esp8266 to control a relay attached to a lava lamp. Every 5 minutes it pings an NTP server and closes the relay if it's the evening.

To put ut bluntly: An arduino with wifi.

Nobody is going to build an IoT device with this MCU running Linux. It's only able to access 64 MB of RAM from its slow cores. There's also limited support for 32-bit RISC-V in distros so anyone looking to run Linux on this will need to build everything themselves. Easier to just get a cheap ARM SoC that can probably run Android.

Or you could just use it as a microcontroller. Networking support is already good. Programming language support is better than you think (C++, Rust, Python, JavaScript). Debugging just works on newer boards.

I imagine that most of these (like almost all embedded chips) are designed primarily for some specific customer or two, and then they dump them on the market generally on the off chance someone else wants them too now that they're essentially capitalized.

I'm actually wrong about S31. The cores are clocked lower than P4. And somehow I thought S31 is 250 MHz 16-bit DDR PSRAM but it's 8-bit only. So if you have an uncompressed video stream over CSI, there's just nowhere to buffer it.

I would never touch anything from there. I do not get how people just flash random binaries to their phones without verifying anything. It is basically asking for malware.

https://github.com/agittins/bermuda

Smart homes are dumb unless you are presence aware. Looking at your phone to do a thing is just moving a light switch to your hand.

The Who is — does the automation make sense for one or many people. If two people are in a room what happens? If one person leaves what happens?

Esp32’s are pivotal in actually making a smart home predict what you want making the home more of a friend, “get on up there Peter Townsend.”

Pete Townshend knows what he did.

"Who is going through this room" to power automations for that individual

it means they're Going Mobile. And they Won't Get Fooled Again.

I'm thinking of building something that emulates a VT-340 terminal. I can take MAME's emulation of the 80186, the ROM dumps, and have something that just translates the 80186 ROM code into a compilable program, with the hardware behavior informed by MAME's description (which is incomplete for the 3xx series).

The s31 wroom-3 modules cost 40CNY from official espressif store. A significant more expensive than S3, but it brings a lot to table.

There are a lot of competitors in China, the BK7258 is arguably better than S3, but cost similar.

And if you are willing to sign NDA, there are much better offer from BES.

Exactly the option is using Raspberry PI instead of ESP32.

I think trying to be everything devalues the original idea.

Universal compatibility only helps if you can actually reach the access point over the most crowded channels in the apartment building.

Some of us have a challenging RF environment and rely on the 5GHz band for reliability, even for low data rates.

802.11a was ratified at the same time as 802.11b, and still doesn't have to fight with cheap baby monitors for bandwidth.

Appreciate the honest feedback. I know such accusations are a tired trope - I never said that the article is AI written, but "pumped up". The article obviously contains a lot of grounded insight, but it instinctively felt a bit Claudish - not only attention grabbing section titles (xy is the biggest downfall), but the A-B structured subtitles (which, I see, is a thing at XDA). It's about the style - I grew up with a lot of classical hardware reporting from the 2000s, Tom's, HardOCP or more mainstream classical Gizmodo or Engadget - and skimming through the link urged me enough to blurp the above, for how I miss the stern, technical, but still fun and gonzo type of reporting nowadays only found in some personal blogs.