SparkFun gator:particle Hookup Guide

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Introduction

Do you have an experiment involving biometrics or particle detection?

SparkFun gator:particle - micro:bit Accessory Board

SparkFun gator:particle - micro:bit Accessory Board

SEN-15271
$10.95

The gator:particle is an amazing tool that uses a high-sensitivity pulse oximeter and heart-rate sensor, the MAX30102. Similar to the SparkFun Particle Sensor, with the MAX30105 high-sensitivity optical sensor, the gator:particle can also be used for particle detection. The primary difference between these boards is that the SparkFun Particle Sensor also uses a green LED that requires more power than the micro:bit can provide. This tutorial will show you how to get started using the gator:particle sensor with the gator:bit (v2) in the micro:bit development environment.

Required Materials

To get started, you'll need a micro:bit to control everything. Each of the products below includes a micro:bit, but the kit and bundle also include some additional accessories that you may want as well.

micro:bit Go Bundle

micro:bit Go Bundle

DEV-14336
$16.50
18
SparkFun Inventor's Kit for micro:bit

SparkFun Inventor's Kit for micro:bit

KIT-15228
$49.95
2

micro:bit Board

DEV-14208
10

To easily use the gator board ecosystem, a gator:bit (v2) will help breakout the necessary pins and you will also need alligator and/or banana cables to connect the gator:bit to the gator:particle.

Alligator Test Leads - Multicolored (10 Pack)

Alligator Test Leads - Multicolored (10 Pack)

PRT-12978
$3.25
4
SparkFun gator:bit v2.0 - micro:bit Carrier Board

SparkFun gator:bit v2.0 - micro:bit Carrier Board

DEV-15162
$19.95
1
Banana to Banana Cable - Right Angle

Banana to Banana Cable - Right Angle

CAB-15368
$4.95

(*These banana cables have a special diameter on the attachment points designed specifically for use with the micro:bit ecosystem. They may or may not be compatible with the banana cables used on your test equipment.)

You may already have some of these materials, so feel free to modify your cart as necessary.

Suggested Reading

The gator:particle sensor is pretty straight forward to use in application. However, you may find the following concepts useful along the way.

Light

Light is a useful tool for the electrical engineer. Understanding how light relates to electronics is a fundamental skill for many projects.

Logic Levels

Learn the difference between 3.3V and 5V devices and logic levels.

I2C

An introduction to I2C, one of the main embedded communications protocols in use today.

MAX30105 Particle and Pulse Ox Sensor Hookup Guide

The SparkFun MAX30105 Particle Sensor is a flexible and powerful sensor enabling sensing of distance, heart rate, particle detection, even the blinking of an eye. Get ready. Set. Shine!

If you aren't familiar with the micro:bit, we recommend reading here for an overview.

We would also recommend taking a look at the following tutorials if you aren't familiar with them.

Getting Started with the micro:bit

The BBC micro:bit is a compact, powerful programming tool that requires no software installation. Read on to learn how to use it YOUR way!

How to Load MicroPython on a Microcontroller Board

This tutorial will show you how to load the MicroPython interpreter onto a variety of development boards.

SparkFun gator:bit v2 Hookup Guide

The gator:bit v2 is a breakout board for the BBC micro:bit. The gator:bit exposes almost every pin on the micro:bit to clippable pad with circuit protection. It also has as built-in addressable LEDs and a built-in buzzer.

Hardware Overview

The gator:particle consists of 4 pads for power and data.

Contacts Direction Description
GND N/A Ground: Reference voltage and ground loop.
3.3V In Power: Provides 3.3V to board.
SDA Bi-directional Data: Data and commands are transmitted between the sensor and microcontroller.
SCL In Clock: The microcontroller provides the timing needed to communicate on the data line.

Power

The specified operating voltage for the MAX30102 is between 1.7V - 2V. For use with the gator:bit (v2) and micro:bit, you should provide 3.3V through the 3V3 and GND pads to keep the logic levels consistent; the 3.3V input is then regulated to 1.8V for the MAX30102.

Power Connections and LED
Power connection pads and power indication LED.

MAX30102

The MAX30102 is a high-sensitivity pulse oximeter and heart-rate sensor that communicates over an I2C bus. The MAX30102 uses both red and IR LEDs along with a very sensitive photodetector for pulse oximetry (SpO2), heart-rate (HR) monitoring, and particle (PM) detection. For the most part, users will only need to know I2C addresses to prevent address conflicts with other devices or sensors.

MAX30102 IC
MAX30102: HR and SpO2 sensor.

Here are some of the characteristics of the MAX30102 sensor from the datasheet:

Characteristic Range
Operating Voltage 1.8V to 2V
Supply Current Heart Rate and SpO2 Mode: 600 to 1200 µA
IR Only Mode: 600 to 1200 µA
Operating Temperature -40°C to 85°C
(ΣΔ) ADC Resolution: 15 to 18-bits (programmable)
Sampling Rate: 50 - 3200 sps (programmable)
IR LED LED Wavelength: 870 to 900 nm (avg. 880 nm)
Forward Voltage: 1.4V
Radiant Power: 6.5 mW
LED Driver Current: 0 to 50 mA (programmable)
Red LED LED Wavelength: 650 to 670 nm (avg. 660 nm)
Forward Voltage: 2.1V
Radiant Power: 9.8 mW
LED Driver Current: 0 to 50 mA (programmable)
Photodetector Spectral Range of Sensitivity: 600 to 900 nm
Radiant Sensitive Area: 1.36 mm2
I2C Address 0xAE - Write Address
0xAF - Read Address

What are Heart-Rate and Oxygen Saturation?

Heart-rate is the speed at which your heart pumps blood through your body. Pulse oximetry is a noninvasive method of determining saturation of oxygen in your blood. However, this is a peripheral measurement is not always a direct reflection of the arterial oxygen saturation (SaO2), but two are correlated enough for clinical purposes. There are a multitude of applications for these measurements; especially, in the medical field.

Here are some examples of studies using HR monitoring and pulse oximetry:

Here are additional resources on how the MAX30102 functions for HR detection and pulse oximetry:

Note: The MAX30102 can be used as a biosensor that for SpO2 and HR measurements on finger tips or earlobes. The sensor does need good contact with constant pressure against the epidermis for accurate results.

What are Particulates?

Particulate matter is the accumulation of matter (solid or liquid) in Earth's atmosphere. These particles vary in size, composition, and distribution. Their effects range from individual health on a microscopic scale to regional climate on a macroscopic scale. Particulate matter is also used in the food industry. Apiarist traditionally use bee smokers when harvesting honey. Smoking is also a method of flavoring and preserving meats and other products.

Here is a link to some experiments involving PM:

For more information on particulate matter and their detection, check out some of these resources:

Note: Particle detection is another application of the MAX30102. The sensor relies on the reflection and scattering of the red and IR light from particles to detect their presence.

I2C Connection

I2C is a communication protocol used to transfer data between controller and peripheral devices. It is a 2-wire connection consisting of SDA (data) and SCL (clock). The protocol is pretty well defined so it can be shared with multiple devices. This is beneficial for daisy chaining multiple devices together on a single bus. The primary thing users will need to watch out for is address conflicts (you can't have devices with the same address).

I2C Connection
I2C connection pads.

Hardware Assembly

Connecting your gator:particle to the gator:bit (v2) is simple. The board can also be daisy-chained with other I2C boards. This can easily be done with alligator cables or these special banana cables.

Hardware Assembly
Hardware assembly of connections used in example. Click to enlarge.
Daisy Chain
Example of daisy chaining multiple I2C gator boards. Click to enlarge.
Gator:UV GND 3V3 SDA SCL
Gator:Bit GND 3.3V OUT P20 (SDA) P19 (SCL)

Adding the MakeCode Extension

Note: This tutorial assumes you are familiar with MakeCode, the gato:bit (v2), and the micro:bit board.

The easiest way to get started using the gator:particle is to use Microsoft MakeCode, a web-based block editor. This tutorial assumes you are familiar with the with MakeCode, the gato:bit (v2), and the micro:bit development board. If this is your first time check out this guides linked in the suggested reading section (above).

Installing Extensions

To get started with using MakeCode with the miccro:bit, head over to the MakeCode for micro:bit website by Microsoft. Then, click the New Project button to start a new project and open the Editor. (*Yes, all you only need to get start coding is a computer with internet access, an up-to-date web browser, and an available USB port!)

MakeCode Website
Click the New Project button to start a new project and open the Editor. Click on image to enlarge.

Once you have the editor up, click on the the Advanced block in the block library to reveal the drop down menu.

Editor
Click on the the Advanced block in the block library to reveal the drop down menu. Click on image to enlarge.

Finally, click on the Extensions block. This should bring up the extensions page. (*Alternatively, you could also click on the extensions link from the settings menu.)

Advanced Block
Click on the the Extensions block to open the extensions page. Click on image to enlarge.

There are two methods for finding the gator:particle extension:

  • Search for the name used on the extension3.
  • Use the link to the GitHub repository for the pxt-package as the search term.

Extensions Page
Use the search bar to find the extension you want to install. Click on image to enlarge.

Note: Unfortunately, it does take time to get an extension approved by the micro:bit Educational Foundation before it can be searchable by name. Part of the requirements for the approval process involves a live product page. Therefore, at the time of the launch of this product, the extension has not been approved yet and the only method of adding the extension is to use the link to the GitHub repository of the pxt-package. We will update this tutorial as soon as the extension has been approved.

Search for the PXT-Package

Search for the gator:particle extension using the GitHub repository link to the pxt-package:

https://github.com/sparkfun/pxt-gator-particle

Search for Extension
Search for Extension. Then, click on the box to add it to the block library. Click on image to enlarge.

Then, click on the box for the extension to add it to the block library. The gator:particle extension should now appear in the block library.

Extension in Block Library
Extension in the block library; click on the block to open menu options. Click on image to enlarge.

To verify that you have added the extension, click on the gator:particle block to make sure that your drop down menu options match the image below.

Menu Options
Available blocks for the gator:particle extension. Click on image to enlarge.

MakeCode Example

Now that you have added the gator:particle extension to the Editor, lets start with some example code. Plug the micro:bit into your computer using an USB micro-B cable after you have assembled your hardware with the instructions from the previous section. The micro:bit should appear on your computer as a removable storage device.

USB Drive
The micro:bit showing up as a USB drive on a Windows computer. Click to enlarge.

To upload new code, this is where you will be copying the downloaded .hex file to later.

Block Functions

initialize gator:particle sensor
This block should be pretty self explanatory, it sets the sensor up to be used. You should use this within the on start block.

get _____ value
This is a value block as indicated by the block's shape. The output is an integer value from 0 to 262,143 for the sensor's detection of the specified wavelength. There is a drop down menu with selectable options for the sensor reading for the block. Below is a description of the available menu options:

  • red- An 18-bit integer value for sensor detection in the IR wavelength (0 and 262,143).
  • infrared- An 18-bit integer value for sensor detection in the IR wavelength (0 and 262,143).
  • With the default LED intensity, I was only able to see a maximum of approximately 120,000. To get higher values, the LED intensity needs to be turned up.

detect heartbeat in _____
This is a value block as indicated by the block's shape. There is a drop down menu with selectable options for the output value of the block. Below is a description of the available menu options:

  • BPM- Outputs a single heart-rate measurement in beats per minute (BPM).
  • AVG- Outputs the average of the last four heart-rate readings in BPM.

Set LED mode to read _____
This block should allows users to designate the LED modes. There are only two opions:

  • red- Only the red LED is used or on.
  • red & infrared- Both the red and IR LEDs are on.
  • There is no option to use only the IR LED.

Change strength of _____ to _____
This block should allows users to control the brightness or intensity of the LEDs.

  1. LED- Users designate which LED to control.
    • red
    • infrared
  2. Strength- Users specify the intensity of the LED. Enter an integer.
    • 0 to 255

Basic Read

Below, is a simple example of how to take simple measurements from the sensor. To use this example, there are multiple options for accessing the .hex file:

  • Replicate the block functions from the display below to copy the example project. Then download the .hex file.
  • Expand the display widow to pull up the example project. Then download the .hex file.
  • Use this link to pull up the example project. Then download the .hex file.
  • Download the .hex file from the button below or the link on the bottom of the display.

The output is redirected over the serial port to avoid conflicts on pins P0 and P1, which are also used for serial communication. To read the sensor values, pull up your favorite serial terminal emulator. Then, connect to the serial port that the micro:bit is on; the default baud rate is 115200 bps. Below, is an example of the sensor output for the example code.

Sample Readings
Example of readings from the sensor.

Troubleshooting Tips

Here are a few tips for troubleshooting this device.

Heart-Rate and SpO2

Make sure that you are making good contact and have constant pressure on the sensor. For the best results, use your finger tip. A special open-source algorithm is used to determine the Heart-Rate and SpO2 measurements. The algorithm is relatively accurate, but is primarily meant for demonstration purposes and should not be used in critical applications for monitoring a person's health.

If you still have questions or issues with this product, please create a post on our forum under the Gator Products topic.

Additionally, if you are an educator and you have class or application based questions, please create a post on our forum under the Educational Products topic.

Resources and Going Further

For more product information, check out the resources below:

Interested in the micro:bit? Check out some of these other micro:bit products:

micro:bit v2 Club Kit - Go Bundle 10-Pack

micro:bit v2 Club Kit - Go Bundle 10-Pack

KIT-17290
$159.95
micro:bit v2 Board

micro:bit v2 Board

DEV-17287
$14.95
2
micro:bit Educator Lab Pack

micro:bit Educator Lab Pack

LAB-15230
$299.95
SparkFun micro:climate kit for micro:bit - v3.0

SparkFun micro:climate kit for micro:bit - v3.0

KIT-16274
$99.95

Need some inspiration for your next project? Check out some of these other micro:bit product tutorials:

SparkFun Inventor's Kit for micro:bit Experiment Guide

This guide contains all the information you will need to explore the twelve circuits of the SparkFun Inventors Kit for micro:bit.

How to Load MicroPython on a Microcontroller Board

This tutorial will show you how to load the MicroPython interpreter onto a variety of development boards.

SparkFun gator:soil Hookup Guide

The gator:soil is analog soil moisture sensor. This tutorial will get you started using the gator:soil with the micro:bit platform.

How to Create a MakeCode Package for Micro:Bit

Learn how to develop code blocks for the Micro:bit in Microsoft MakeCode!