sparkfun gator:particle Technical document

SparkFun gator:particle Hookup Guide
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Introduction
Do you have an experiment involving biometrics or particle detection?
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.
SparkFun gator:particle - micro:bit Accessory Board
 SEN-15271
Product Showcase: gator:boards - micro:bit Accessory BoardsProduct Showcase: gator:boards - micro:bit Accessory Boards

Required Materials
To get started, you'll need a micro:bit to control everything.
To easily use the gator board ecosystem, one of the gator:bit boards will help breakout the necessary pins. You will
also need alligator cables to connect the gator:bit to the gator:particle.
SparkFun Inventor's Kit for micro:bit
 KIT-14542
micro:bit Go Bundle
 DEV-14336
micro:bit Board
 DEV-14208

Suggested Reading
There isn't much to learning how to use the gator:particle sensor. However, you may find the following concepts
useful along the way.
SparkFun gator:bit v2.0 - micro:bit Carrier Board
 DEV-15162
Alligator Test Leads - Multicolored (10 Pack)
 PRT-12978
SparkFun gator:bit
 DEV-14484
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.

If you aren't familiar with the micro:bit, we recommend reading here for an overview.
micro:bit Ecosystem
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!
Product Showcase: micro:bit and SparkFun bitsProduct Showcase: micro:bit and SparkFun bits

We would also recommend taking a look at the following tutorials if you aren't familiar with them.
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
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!
Getting Started with MicroPython and the
SparkFun Inventor's Kit for micro:bit
Learn MicroPython with the 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: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.

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 connection pads and power indication LED.
MAX30102
The MAX30102 is a high-sensitivity pulse oximeter and heart-rate sensor that communicates over an I C bus. The
MAX30102 uses both red and IR LEDs along with a very sensitive photodetector for pulse oximetry (SpO ), heart-
rate (HR) monitoring, and particle (PM) detection. For the most part, users will only need to know I C addresses to
prevent address conflicts with other devices or sensors.
MAX30102: HR and SpO 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 SpO 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)
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2
2
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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 mm
I C 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 (SaO ), 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:
Accuracy of pulse oximeters in estimating heart rate at rest and during exercise
Pulse oximetry: Understanding its basic principles facilitates appreciation of its limitations PDF Download
Experiment: Exercise, Blood Pressure, and Oxygen Saturation Levels
Here are additional resources on how the MAX30102 functions for HR detection and pulse oximetry:
AN6410: Signal to Noise Ratio (PDF)
AN6433: Depth Penetration for Biosensors (PDF)
Maxim: Open Source Heart Rate Algorithm (Arduino)
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Heart Rate Monitor DemoHeart Rate Monitor Demo

Note: The MAX30102 can be used as a biosensor that for SpO 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:
Hands-on Activity: Particulate Matter: For Your Eyes Only
For more information on particulate matter and their detection, check out some of these resources:
Particulate Matter (PM) Basics
Optical Monitoring of Particulate Matter
Maxim: Using Optical Sensors to Detect Particles
Optical Particle Counters
Smoke Detectors
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.
I C Connection
I C is a communication protocol used to transfer data between master and slave 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).
I C connection pads.
Hardware Assembly
Connecting your gator:particle to the gator:bit (v2) is simple. The board can also be daisy-chained with other I C
boards. This can easily be done with alligator cables.
2
2
2
2
2

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.
If you have not previously used MakeCode, please check out the Quick Start Guide fro micro:bit.
If this is your first time using a micro:bit, please review our Getting Started with the micro:bit guide.
If this is your first time using the gato:bit (v2), please review our SparkFun gator:bit v2 Hookup Guide.
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!)
Hardware assembly of connections used in example. Click to enlarge.
Example of daisy chaining multiple I C gator boards. Click to enlarge.
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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.
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.)
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 extension .
Use the link to the GitHub repository for the pxt-package as the search term.
Use the search bar to find the extension you want to install. Click on image to enlarge.
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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. 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 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.
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.
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.
DOWNLOAD .HEX FILE FOR EXAMPLE
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.
serial redirect to USB
initialize gator:Particle sensor
on start
join Particle =
" " get red value Heart Rat "
serial write line
forever
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Example of readings from the sensor.
Troubleshooting Tips
Here are a few tips for troubleshooting this device.
Heart-Rate and SpO
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 SpO 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:
Schematic (PDF)
Eagle Files (ZIP)
MAX30102 Datasheet (PDF)
AN6410: Signal to Noise Ratio (PDF)
AN6433: Depth Penetration for Biosensors (PDF)
gator:particle PXT Package
GitHub Product Repo
micro:bit Landing Page
SFE Product Showcase
Interested in the micro:bit? Check out some of these other micro:bit products:
2
2

Need some inspiration for your next project? Check out some of these other micro:bit product tutorials:
SparkFun Inventor's Kit for micro:bit Lab Pack
 LAB-15229
SparkFun gator:bit v2.0 - micro:bit Carrier Board
 DEV-15162
micro:bit Educator Lab Pack
 LAB-15230
SparkFun Inventor's Kit for micro:bit
 KIT-14542
micro:arcade Kit Experiment Guide
We love games! We love writing games, building
games and yes, even building game consoles. So we
want to introduce to you the micro:arcade kit for the
micro:bit!
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The gator:soil is analog soil moisture sensor. This
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