HardLabs

Heart rate monitor

jkravanja·heart_rate_monitor

Heart rate monitor PCB layout, top view — open source Nordic nRF board by jkravanja

About the Heart rate monitor PCB

Heart rate monitor is an open source Nordic nRF PCB design by jkravanja, published on GitHub. It is a 2-layer board measuring 50 × 50 mm, with 72 components from 50 distinct parts.

Its main chip is the NRF51822, from the Nordic nRF family. Other key parts include the ANTENNA Johanson 2450AT18A100E, AFE4400, MMA8452Q and CAT24M01. By type, the board carries 29 capacitors, 15 resistors, 6 diodes, 5 ICs, 5 transistors and 3 crystals.

It belongs with the iot & wireless, wearables and sensors designs in this gallery.

From the project

Heart rate monitor designed in KiCad, using Nordic NRF51822 bluetooth module and TI AFE4400 heart rate module.

The repository contains a KiCad design of a 5x5 cm heart rate monitor breakout board. Some libraries were borrowed from Guan Yang's github projects (https://github.com/guanix/boards). Also, some design aspects of the circuit were inspired by HackManhattan Nordic nrf51822 beakout board (http://dangerousprototypes.com/2013/05/19/hackmanhattans-nordic-nrf51822-breakout-board/)

Heart rate monitor, from the project README
From the project README

Main components on the Heart rate monitor

NRF51822ANTENNA Johanson 2450AT18A100EAFE4400MMA8452QCAT24M01

Heart rate monitor bill of materials (BOM)

72 components, 50 distinct parts.

QtyPartRefs
1
NRF51822
IC1
1
ANTENNA Johanson 2450AT18A100E
U1
1
AFE4400
U2
1
MMA8452Q
U3
1
CAT24M01
U4
3
MOSFET_P
Q1, Q4, Q5
2
MOSFET_N
Q2, Q3
1
16.000MHZ
X1
1
32.768 kHz
X2
1
8 MHz
X3
1
CONN_5X2
P1
1
CONN_2
P2
1
CONN_3X2
P3
1
P***
1PIN
1
Balun Johanson 2450BM14A0002
B1
1
BATTERY
BT1
1
SWITCH-4
SW1
1
LED
D1
1
PHOTODIODE
D2
1
PHOTODIODE
D3
Show 30 more
QtyPartRefs
1
IR
D4
1
RED
D5
1
LED
D6
1
10uH
L4
1
15nH
L5
3
0.1 uF
C1, C2, C16
1
2.2nF
C3
2
4.7uF
C4, C7
4
20pF
C5, C6, C13, C14
4
0.1uF
C8, C11, C15, C19
1
1nF
C9
1
47nF
C10
2
1uF
C12, C20
2
33p
C17, C18
2
2.2uF
C21, C22
1
4.7 uF
C23
1
0.01 uF
C24
2
1 nF
C25, C29
1
220 nF
C26
2
1 uF
C27, C28
1
12K
R1
1
100R
R2
4
4.7k
R3, R7, R8, R9
1
10k
R4
1
10
R5
1
1k
R6
1
1 M
R10
2
100 k
R11, R12
1
3 k
R13
2
R
R14, R15

Heart rate monitor design files

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

Heart rate monitor: common questions

What microcontroller does the Heart rate monitor use?

The Heart rate monitor is built around the NRF51822, from the Nordic nRF family.

How big is the Heart rate monitor PCB?

The Heart rate monitor measures 50 × 50 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Heart rate monitor?

72 components, from 50 distinct parts. The full bill of materials is listed on this page.

Where can I download the Heart rate monitor design files?

From the jkravanja/heart_rate_monitor repository on GitHub, which has the KiCad layout; the links under Design files point to each one.

Can I use the Heart rate monitor design in my own project?

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

Can I test firmware for the Heart rate monitor 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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