ESP32

The ESP32 is a family of low-cost microcontrollers from Espressif Systems of Shanghai that combine one or two processor cores, memory, a Wi-Fi radio and a Bluetooth radio on one chip. The ESP32-S3 sits in both devices that Molecular Reality Corporation has called the MR1, the MR1 Molecular Streaming Device and the MR1 Nanopore Reader, where it receives the digitized current of a nanopore, sends it out over USB and serves a thinned-out copy of the trace over Wi-Fi to an oscilloscope in a web page.

Espressif presented the first ESP32 at a press conference in Shanghai on September 6, 2016, as the successor of the ESP8266.^[1] It has one or two Xtensa LX6 cores at up to 240 MHz, 520 KB of on-chip SRAM, and Bluetooth 4.2.^[2] The family has since grown to series with Xtensa cores, among them the single-core S2 and the dual-core S3, and series with RISC-V cores, among them the single-core C series, mostly at 160 MHz, and the dual-core P4 at 400 MHz.^[3]

The ESP32-S3 has two Xtensa LX7 cores at up to 240 MHz, 512 KB of SRAM, 2.4 GHz Wi-Fi (802.11 b/g/n), Bluetooth 5 (LE), 45 programmable pins and a full-speed USB controller, which runs at 12 Mbit/s.^[4] Its instruction set has extensions with 128-bit registers and vector operations for "specific AI and DSP (Digital Signal Processing) algorithms". Two 12-bit successive-approximation converters serve up to 20 analog pins, with a note in the datasheet that the channels of the second converter cannot be used while Wi-Fi is on. The measurement of the pore current does not use them.

The older MR1, the handheld, pairs the S3 with an LMP7721 amplifier, a MAX11169 converter of 16 bits and an MCP4822 converter that sets the voltage across the pore.^[5] The open design of the reader splits the work between the two cores. Core 1 runs a loop that samples an external converter of 16 or 18 bits 100,000 times a second by direct memory access and sends the samples out over USB. Core 0 runs Wi-Fi, a web server, the oscilloscope, which receives the trace decimated to 1,000 points a second, and the serial link to the pump module, which has its own microcontroller, an STM32G431.^[6]

A stream of 146-byte frames of 64 samples each, at 1,562.5 frames a second, is about 1.83 Mbit/s and fits within full-speed USB. The README of the repository nevertheless calls the interface "native high-speed USB CDC", and the data-acquisition specification lists both 12 Mbit/s and 480 Mbit/s, the latter being a speed the chip does not have.^[6] The module on the board differed between files. The schematic and the firmware headers named an ESP32-S3-MINI-1U, whose part number ending in N8 means 8 MB of flash and no extra RAM, while the bill of materials listed an ESP32-S3-WROOM-1-N16R8, with 16 MB of flash and 8 MB of PSRAM. A commit of October 21, 2026 replaced the second with the first.^[7][8]

A second bench of the company in San Mateo, California, streams from a rig built around an ESP32.^[5]

The first version of the company's essay on a nanopore world model proposed learning on the devices. The second lists "Federated on ESP32" among its corrections and says that the ESP32 in the company's devices "cannot backprop a ViT or Mamba", so it should run a frozen model while the fleet of devices, with the World Particle Project, supplies the training data.^[9] The memory explains the verdict. A model of 5 million parameters at one byte each takes 5 MB, ten times the 512 KB of SRAM on the S3, before any activations or gradients are stored.

The instructions of the company's character Maxine contain a line about the board: "Keltar talks about star-dust; I just need to figure out how to mitigate parasitic capacitance on this ESP32 board!"^[10] Capacitance at the input of the amplifier turns its voltage noise into current noise that grows with frequency, as described under Nanopore noise. In the reader the amplifier is a small board under the cartridge, apart from the board that carries the microcontroller and its radio.

• Transimpedance amplifier
• Analog front end
• Analog-to-digital converter
• Keltar