Schematic representation of a device
For CPU we selected STM32F407VE, which is based on the high-performance 32-bit ARM®Cortex®-M4 RISC core operating at a frequency of up to 168 MHz with 3 SPI ports, 2 I2C, 2 UART.
For ADC of course – ADS1299 from Texas Instruments (Why still not exist something newer? )
A power supply is important. For positive voltage, we used the following voltage regulators – t3042 Ultralow RMS Noise: 0.8µVRMS (10Hz to 100kHz) and Ultralow Spot Noise: 2nV / √Hz at 10kHz, for negative lt3094 Ultralow RMS Noise: 0.8µVRMS (10Hz to 100kHz) Ultralow Spot Noise : 2.2nV / √Hz at 10kHz.
Reference voltage for ADC external or internal (we did research, the result will public). TI recommendation – REF5045. We used – ADR4525.
Send data – by ESP32 (TCP-IP), Bluetooth, Radio and UART.
Diameter – 50 mm