Grove Heart Rate Sensor

Introduction

In this section, is my story on why did I bought this sensor. If you not interesting then you can just skip it.

I'm planning to do some project to log heart rate value.

At first, I was thinking that I can get it from some activity tracker or smart watch. I actually have a Garmin vivoactive 3 so this seem to be a good plan. They have an api for third party application to be able to access their watch at realtime but you have to send them the request and wait for their approval sadly I didn't get any response 😔

So, I moved to plan B, let's use some maker friendly device. I'm googling around try to find a heart rate sensor, which can be connect to some microcontroller like Arduino or raspberry pi. Finally this sensor pop up in one of the local store in my hometown (fast delivery!!!).

Anyone living in Bangkok (well I assume they can delivery to any place in Thai) and interest to buy some "maker" stuff you can check them up. The store name is ThaiEasyElec.

A Bit About the Sensor

Grove Heart Rate Sensor, is actually not just a sensor. It is a SOM(System On Module). it has two major component.

1. Optical sensor with Green LED

This is the actual heart rate sensor. It send out the green light to our skin and measure back the reflect light. When heart is beating it create the variation in blood movement in the vessel and this variation affect the amount of light reflect back into our sensor thus indicate the heart rate.

2. STM32

a microcontroller unit that read the raw data from the sensor and calculate the heart rate out of it.

Read the datasheet

Well, before start please check the sensor wiki and datasheet to so if it is something meet with you usage or not. This is something I'm forgot to do and I regret about it. I actually want a sensor that I can read out a raw data out of it, something that I can see an actual heart rate graph. But this one the sensor calculate the heart rate for you and give out just a rpm value.

Hardware Setup

1. Grove Heart Rate Sensor

it's obvious right. the one I bought come with shell so it can be easily attach can be wear.

2. Beaglebone Green Wireless (BBGW)

I already have this board. The good thing about it is that it has a grove connector that can connect to our Grove Heart Rate Sensor. But actually you can you any hardware with i2c input

Running An Example Code

Next Step, we going to find an example code to see how to use it.

For BBGW, if you open a cloud ide (accessing cloud ide on you BBGW: http://192.168.7.2:3000/ide.html). There's actually an example code for this sensor. However, I couldn't make it run. Anyone who knows how to please help me 😂

Finally, I found a tutorial that is work for me here is the link.

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