Ecgrok

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

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