Ecgrok

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The ecgrok-tiny is a very small, Open Hardware and open-source, experimental, DIY, USB-based 2-channel ECG.

The schematics and layouts are done from scratch in KiCad, and are released under the CC-BY-SA 4.0 license.

The microcontroller firmware is licensed under the GNU LGPLv3+ and uses libopencm3 (GNU LGPLv3+ as well).

Device

Note: Most of this is work in progress and might change at any time!

Item ecgrok-tiny
Goals
  • Tiny
  • Open Hardware
  • "Just for fun" project, doesn't have to be practical
  • Sacrifices a lot of things for reduced size
Author Uwe Hermann
Status in progress
Hardware license CC-BY-SA 4.0
Size 20 mm x 10 mm (WIP, might change)
Layout specs
  • Double-sided 2-layer PCB/layout
  • Components soldered on both sides
  • 1.6 mm PCB thickness
  • 5 mil traces, 6 mil trace clearance
  • 8 mil via drill hole diameter, 5 mil annular ring
ECG channels 2
Microcontroller ST STM32F042K6
ADC TI ADS1292
Input protection None whatsoever
Galvanic isolation None, using a USB isolator is highly recommended for safety reasons!
Crystal None(?)
USB USB 2.0 Full-Speed (12Mbit/s)
USB connector USB Micro-B SMD
ECG lead wire connector 3.5mm stereo audio jack
Passives Only 0402
LED 1x 0402 LED

Bill of materials

Note: All prices are for single quantities, most parts get a lot cheaper if you buy higher quantities.

Qty Device Footprint Size Value Refdes Digikey Mouser Aliexpress Comments
Required parts
1 ST STM32F042K6U6 UFQFPN32 5 mm x 5 mm IC1 2.29€ 2.21€ Microcontroller
1 TI ADS1292IRSMT 32-VQFN 4 mm x 4 mm IC2 9.06€ 9.58€ ADC
1 Switchcraft 35RASMT2BHNTRX custom 17 mm x 6 mm CONN1 0.78€ 0.72€ 3.5mm stereo audio jack
1 Amphenol FCI 10118192-0001LF custom 9.8 mm x 5.6 mm U1 0.36€ 0.36€ USB Micro-B SMD connector
Optional (but highly recommended!) parts
1 MT Technology Noname custom 3.28€ ECG electrode lead wires, 3.5mm headphone plug, 90° angle
1 PMSOEHT DF-00147 custom 16.96€ ECG electrode lead wires, 3.5mm headphone plug, straight (alternative)
1 CONTECMED ECG patches custom 8.44€ 20 ECG electrode patches
1 Deek-Robot 1E0185 custom 8.94€ USB isolator

FAQ

Resources