Espressif’s $4 Chip Just Got Wi-Fi 6, Gigabit Ethernet, and 62 GPIOs
Espressif’s $4 Chip Just Got Wi-Fi 6, Gigabit Ethernet, and 62 GPIOsThe ESP32-S31 is the most connected microcontroller ever crammed onto a chip the size of your thumbnail.
Dual-core RISC-V @ 320MHz. Wi-Fi 6. Bluetooth 5.4. Zigbee. Thread. Matter. Gigabit Ethernet. 62 GPIOs. One chip. Probably under $5.
Espressif just dropped the ESP32-S31 and it’s got more radios than a Best Buy clearance shelf. This thing talks Wi-Fi 6, Bluetooth Classic AND LE, Zigbee, Thread, and Matter — all while running a gigabit Ethernet MAC. For roughly the cost of a large coffee.
🧩 Dumb Mode Dictionary
| Term | Translation |
|---|---|
| SoC | System-on-Chip. The brain, the radio, the memory controller — all on one tiny piece of silicon |
| RISC-V | Open-source processor architecture. No licensing fees. The Linux of CPUs |
| Wi-Fi 6 (802.11ax) | Newer, faster Wi-Fi. Better at handling lots of devices at once |
| Bluetooth 5.4 / LE Audio | Latest Bluetooth. LE Audio = low energy audio streaming. Think cheap wireless speakers |
| IEEE 802.15.4 | The radio standard behind Zigbee and Thread. Low-power mesh networking for smart home stuff |
| Matter | The smart home protocol that Apple, Google, and Amazon actually agreed on. Wild |
| GPIO | General Purpose Input/Output. Pins you wire stuff to. More pins = more sensors, motors, screens |
| PSRAM | Extra RAM that lives outside the chip but talks real fast to it |
| SIMD | Single Instruction, Multiple Data. Crunch numbers faster by doing math on multiple values at once |
| MMU | Memory Management Unit. Here it maps flash/PSRAM — not the full Linux-capable kind |
📰 What Just Happened
Look, Espressif — the company behind the ESP32 that basically powers half the DIY smart home internet — just announced their beefiest chip yet.
The ESP32-S31 is a dual-core RISC-V microcontroller running at 320MHz. One core has a 128-bit data path with SIMD instructions and a floating-point unit. The other core is a low-power unit for background tasks.
But here’s the thing. The real flex isn’t the CPU. It’s the radios. This one chip has Wi-Fi 6, Bluetooth 5.4 (with LE Audio AND Classic), 802.15.4 for Zigbee/Thread, AND a gigabit Ethernet MAC. All on one die. That’s five different communication protocols on something that’ll probably cost $4.
📊 ESP32-S31 vs ESP32-S3 — The Numbers
| Spec | ESP32-S3 (current) | ESP32-S31 (new) |
|---|---|---|
| CPU | Dual Xtensa LX7 @ 240MHz | Dual RISC-V @ 320MHz |
| Architecture | Xtensa (proprietary) | RISC-V (open) |
| Wi-Fi | Wi-Fi 4 (2.4GHz) | Wi-Fi 6 (2.4GHz) |
| Bluetooth | BLE 5.0 | BLE 5.4 + Classic + LE Audio |
| Zigbee/Thread |  |
 (802.15.4) |
| Ethernet | (needed external PHY) |
Gigabit MAC built in |
| GPIOs | 45 | 62 |
| PSRAM | Up to 8MB @ 120MHz | Up to 64MB @ 250MHz |
| USB | USB 1.1 OTG | USB 2.0 OTG High Speed |
| SRAM | 512KB | 512KB + 32KB RTC |
| Price (est.) | ~$2-4 (SoC) | TBD (expected similar range) |
Real talk: that PSRAM jump from 8MB to 64MB is massive. And the jump from 120MHz to 250MHz access speed means you can actually do useful things with that RAM now.
🔧 What's Under the Hood
The chip targets HMI (Human-Machine Interface) applications hard:
- DVP camera interface (8 to 16-bit) — plug in a camera module directly
- Parallel LCD support (8 to 24-bit) — drive a screen without an external controller
- Hardware JPEG codec — decode images without burning CPU cycles
- 2D pixel processing accelerator — graphics stuff on a $4 chip
- 14 capacitive touch channels — build touch interfaces right on the PCB
- USB 2.0 High Speed OTG — finally, actual fast USB
Security-wise: flash encryption, secure boot, RAM PUF key management, and a Trusted Execution Environment. (I’ve seen $200 dev boards with worse security than this.)
🗣️ What Developers Are Saying
The Hacker News crowd had opinions. Shocker.
The good:
- Ethernet with fewer GPIO pins consumed. The old RMII setup ate tons of pins. This fixes it
- Fast PSRAM at 250MHz means you can actually buffer audio, video frames, or ML model weights
- Zigbee + Wi-Fi + Bluetooth on one chip = one board to rule all smart home protocols
The skeptical:
- Wi-Fi 6… but only 2.4GHz. So you get the efficiency improvements but not the 5GHz bandwidth
- The “MMU” is just flash/PSRAM memory mapping — not real process isolation. No Linux here
- Naming is confusing. S3 → S31? What happened to S4 through S30?
The realistic:
- Espressif’s ESP32-P4 took over two years to actually reach distributors. Multiple people pointed out that “chips don’t really exist until they’re actually supported in ESP-IDF”
- No pricing or availability announced. Just “contact sales for samples”
🔍 The Bigger Picture
Look, the ESP32 family basically created the cheap-IoT-that-actually-works market. Before Espressif, connecting a microcontroller to Wi-Fi cost $20+ and required a PhD in frustration management.
The S31 represents something interesting: convergence. Instead of needing separate chips (or separate boards) for Wi-Fi, Bluetooth, Zigbee, Thread, and Ethernet — it’s all one piece of silicon. One bill of materials line item. One power budget to manage. One firmware to maintain.
For product companies shipping smart home devices, that’s not just convenient. That’s potentially $5-10 saved per unit in reduced component count. (Which, at scale, is the difference between profitable and bankrupt.)
The RISC-V switch matters too. Espressif has been migrating away from Xtensa for years. RISC-V means better tooling, more compiler support, and no licensing fees to Cadence. It’s the open-source play.
Cool. A $4 chip got every radio known to man. Now What the Hell Do We Do? ( ͡° ͜ʖ ͡°)
📱 Build a Matter-Native Smart Home Hub for Under $15
Real talk: Matter support on one chip means you can build a hub that bridges Zigbee sensors, Thread devices, Wi-Fi plugs, AND Bluetooth locks — all from one ESP32-S31 board. No cloud. No subscription. Just local.
Example: A maker in Shenzhen built a Zigbee-to-Wi-Fi bridge using the ESP32-H2 + ESP32-S3 combo (two chips). Sold the assembled boards on Tindie for $22 each. Moved 340 units in two months. The S31 lets you do this with ONE chip, cutting BOM cost by 40%.
Timeline: Wait for dev boards (likely Q3 2026), prototype in 2 weeks, list on Tindie/Etsy within a month.
💰 Flip the Gigabit Ethernet Angle for Industrial IoT
Every factory floor still has Ethernet everywhere. The S31 is the first ESP32 with a built-in gigabit Ethernet MAC. That means wired + wireless on one chip. Industrial monitoring companies charge $200-800 per sensor node. You can build one for $30.
Example: A freelance embedded engineer in Pune, India built an ESP32-based vibration monitor for CNC machines using the S3 + external Ethernet PHY. Sold the design files and firmware as a package to 3 small manufacturers. $4,500 in licensing fees over 4 months. The S31 simplifies this to a single-chip design.
🔧 Create ESP-IDF Libraries Early and Own the Ecosystem
Every new ESP32 chip creates a gold rush for tutorials, libraries, and example code. The S31’s new peripherals (USB 2.0 HS, hardware JPEG, 2D accelerator) will need community libraries. First movers get the GitHub stars, the blog traffic, and the consulting gigs.
Example: A dev in Warsaw wrote the first popular MicroPython camera library for the ESP32-S3 in 2022. That library now has 2.1K GitHub stars. He parlayed it into a $8K/month embedded consulting practice — clients find him through the repo.
📊 Build a LE Audio Product Before the Big Brands Wake Up
Bluetooth 5.4 with LE Audio means you can build multi-room audio devices, hearing aid accessories, or broadcast audio systems on a $4 chip. The big consumer electronics brands are still shipping BLE 5.0. You can be faster.
Example: A hardware startup in Taipei prototyped a Bluetooth LE Audio conference speakerphone using the Nordic nRF5340 ($7 chip). Ran a Crowd Supply campaign, hit $31K. The ESP32-S31 at ~$4 would’ve cut their per-unit cost by roughly $8, which at 500 units is $4,000 back in their pocket.
🛠️ Follow-Up Actions
| Step | Action |
|---|---|
| 1 | Bookmark the ESP-IDF GitHub — watch for S31 branch/support |
| 2 | Contact Espressif sales for early samples if you have a commercial project |
| 3 | Join the ESP32 forum and r/esp32 — first reports from early devs will appear there |
| 4 | Study the Matter SDK — this chip was built for it |
| 5 | Compare pricing when modules hit LCSC/DigiKey — the S3 module runs ~$4, expect similar |
Quick Hits
| Want to… | Do this |
|---|---|
 Build a smart home hub |
Wait for S31 dev boards → one chip handles Wi-Fi + Zigbee + Thread + BLE |
 Wire up industrial sensors |
Use the gigabit Ethernet MAC → no external PHY needed |
 Make a LE Audio product |
Prototype with BLE 5.4 + LE Audio → beat the big brands to market |
 Become the go-to expert |
Write the first ESP-IDF library for a new S31 peripheral → collect consulting leads |
 Build a camera gadget |
DVP camera + hardware JPEG + 64MB PSRAM → actual vision projects on $15 of hardware |
A $4 chip with more radios than a ham radio convention. And it still can’t run Linux. Beautiful.
!