HardLabs

WatchEMS

humancomputerintegration·watchEMS·hardware/pcb/wrist_ems_12_electrodes.kicad_pcb

WatchEMS PCB layout, top view — open source Nordic nRF board by humancomputerintegration

About the WatchEMS PCB

WatchEMS is an open source Nordic nRF PCB design by humancomputerintegration, published on GitHub. It is a 2-layer board measuring 105.4 × 25.4 mm, with 131 components from 63 distinct parts.

Its main chip is the XIAO-nRF52840-Sense-14P-2.54-21X17.8MM)_onlyPins, from the Nordic nRF family. Other key parts include the TLP188(TPL,E, DAC8830ID, OPA4205APWT, LT3757AEMSE and 74AHCT595. By type, the board carries 50 resistors, 34 ICs, 23 capacitors, 13 connectors, 5 transistors and 2 diodes.

From the project

This repository contains the source code used in the research publication "Can a Smartwatch Move Your Fingers?" from the Human-Computer Integration Lab at the University of Chicago.

This repository contains the source code used in the research publication "Can a Smartwatch Move Your Fingers?" from the Human-Computer Integration Lab at the University of Chicago.

When using or building upon this device in an academic publication, please consider citing as follows:

ACM Reference Format: Akifumi Takahashi, Yudai Tanaka, Archit Tamhane, Alan Shen, Shan-Yuan Teng, and Pedro Lopes. 2024. Can a Smartwatch Move Your Fingers? Compact and Practical Electrical Muscle Stimulation in a Smartwatch. In The 37th Annual ACM Symposium on User Interface Software and Technology (UIST ’24)…

Main components on the WatchEMS

TLP188(TPL,EDAC8830IDOPA4205APWTLT3757AEMSE74AHCT595TPS62A01DRLRTPS613222ADBV

WatchEMS bill of materials (BOM)

131 components, 63 distinct parts — part numbers from the project's BOM.

QtyPartRefs
24
TLP188(TPL,E
TLP188_TPL,E
IC1, IC2, IC3, IC4, IC5, IC6, IC7, IC8 +16
1
DAC8830ID
IC25
1
OPA4205APWT
IC26
1
LT3757AEMSE
MCP73812T-420I-OT
U1
1
SeeeduinoXIAO_onlyPinHeader
U2
3
74AHCT595
U3, U4, U5
1
74AHCT595
LT3757AEMSE
U6
1
TPS62A01DRLR
XPS62A01DRLR
U7
1
TPS613222ADBV
U8
1
RSR030N06HZGTL
RSR030N06TL
Q1
3
MMBTA92LT1G
Q2, Q4, Q5
1
DMN30H4D0L
Q3
1
CONN_01X07_PIN
Conn_01x02_Pin
J1
3
CONN_01X04_PIN
Conn_01x07_Pin
J2, J4, J7
5
CONN_01X07_PIN
Conn_01x07_Pin
J3, J5, J6, J11, J12
2
CONN_01X07_PIN
Conn_01x04_Pin
J8, J9
1
CONN_01X04_PIN
Conn_01x04_Pin
J10
1
Conn_01x07_Pin
J13
1
Jumper_2_Open
JP3
1
ATB322515-0110-T000
T1
Show 43 more
QtyPartRefs
1
RF081MM2STR
D1
1
NSVR1020MW2T1G
D2
1
DFE252012F-4R7M=P2
4.7uH
L1
1
DFE252012F-1R0M=P2
1uH
L2
1
68NF
1nF
C1
3
68NF
47uF
C2, C3, C4
1
220PF
0.1uF
C5
1
10NF
22nF
C6
1
0.1UF
100pF
C7
1
22NF
47uF
C8
1
1NF
10nF
C9
1
220pF
C10
4
100nF
C11, C12, C13, C14
2
100nF
C15, C16
1
10uF
C17
1
1nF
C18
2
4.7uF
C19, C20
1
120pF
C21
2
47uF
C22, C23
1
100K
100k
R1
3
100k
R2, R29, R49
1
47K
10k
R3
21
330
R4, R5, R9, R10, R11, R12, R13, R14 +13
1
6.8K
330
R6
1
0.02
330
R7
1
16K
330
R8
1
130k(100kHz)
R28
1
240k
R30
1
6.8k
R31
2
22
R32, R34
1
UCR03EWPFSR020
0.02
R33
4
499k
R35, R36, R37, R50
1
16k
R38
1
300k
R39
1
200k
R40
1
1k
R41
1
1k3
R42
1
10K
100
R43
1
1M
R44
1
30k
R45
1
100
R46
1
100
22
R47
1
453k
R48

WatchEMS design files

The KiCad project lives in the humancomputerintegration/watchEMS repository on GitHub; these links point at the commit this page was built from.

WatchEMS: common questions

What microcontroller does the WatchEMS use?

The WatchEMS is built around the XIAO-nRF52840-Sense-14P-2.54-21X17.8MM)_onlyPins, from the Nordic nRF family.

How big is the WatchEMS PCB?

The WatchEMS measures 105.4 × 25.4 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the WatchEMS?

131 components, from 63 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.

Where can I download the WatchEMS design files?

From the humancomputerintegration/watchEMS repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.

Can I use the WatchEMS design in my own project?

The repository has no license, so all rights stay with humancomputerintegration. Use it as a reference, and ask the author before reusing the design.

Can I test firmware for the WatchEMS without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug Nordic nRF firmware against it before you order a PCB.

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