TinyML: Machine Learning on Raspberry Pi Pico with Tensorflow Lite Micro and Arducam (Featuring Person Detection)

The Future of Machine Learning Is Tiny

The future of machine learning is tiny.Tweet

From Pete Warden, technical lead of the mobile and embedded TensorFlow group in Google’s Brain team.

Machine learning, seen as a part of artificial intelligence, is the study of computer algorithms that improve automatically through experience. 

Tiny machine learning (tinyML) is the intersection of machine learning and embedded internet of things (IoT) devices. The field has the potential to revolutionize many industries.

Before we start, here is a brief introduction to this emerging field from HarvardX.

Tensorflow Lite Micro (tflmicro)

TensorFlow Lite for Microcontrollers is designed to run machine learning models on microcontrollers and other devices with only a few kilobytes of memory.

It supports microcontroller platforms like Arduino Nano 33 BLE Sense, ESP32, STM32F746 Discovery kit, and so on. Since the release of the $4 Raspberry Pi Pico, which has gained increasing popularity among makers, Arducam has been trying to bring what’s possible on other microcontroller platforms to Pico.

Getting started with Machine Learning with Pico

This article is a tutorial on using the machine learning framework Tensorflow Lite Micro on the Pico for Person Detection. If you are more interested in the camera part, check out our Raspberry Pi Pico Camera series.

Demo 1: Person Detection on RPi Pico

Demo 2: Person Detection on Arducam Pico4ML

Demo 3: Magic Wand w/ Pico4ML

Demo 4: Wake-Word Recognition w/ Pico4ML

Demo 5: Arducam HM01B0 Camera for Raspberry Pi Pico

Components and Supplies

Complete All-in-One Pico Person Detection Bundle

Tiny Machine Learning Person Detection Bundle for Raspberry Pi Pico

$39.99

Get A Bundle

Available now: Pico4ML, one dev board for all Tensorflow Light Micro Examples

RP2040 Dev Board w/ QVGA Camera, Microphone, LCD & More

🛒Buy Pico4ML now >

Components of Pico person detection project

See Getting Started with the Raspberry Pi Pico and the README in the pico-sdk for information on getting up and running.

Quick Pico Setup

If you are developing for Raspberry Pi Pico on Raspberry Pi 4B, or the Raspberry Pi 400, most of the installation steps in this Getting Started guide can be skipped by running the setup script. You can get this script by doing the following:

git clone https://github.com/raspberrypi/pico-setup.git

Then run:

 pico-setup/pico_setup.sh

The script will:

• Create a directory called pico
• Install required dependencies
• Download the pico-sdk, pico-examples, pico-extras, and pico-playground repositories
• Define PICO_SDK_PATH, PICO_EXAMPLES_PATH, PICO_EXTRAS_PATH, and PICO_PLAYGROUND_PATH in your ~/.bashrc
• Build the blink and hello_world examples in pico-examples/build/blink and pico-examples/build/hello_world
• Download and build picotool (see Appendix B). Copy it to /usr/local/bin. • Download and build picoprobe (see Appendix A).
• Download and compile OpenOCD (for debug support)
• Download and install Visual Studio Code
• Install the required Visual Studio Code extensions (see Chapter 6 for more details)
• Configure the Raspberry Pi UART for use with Raspberry Pi Pico

Once it has run, you will need to reboot your Raspberry Pi,

sudo reboot

Person Detection

Person Detection Diagram

• Download RPI-Pico-Cam

git clone https://github.com/ArduCAM/RPI-Pico-Cam.git

• Compile

cd RPI-Pico-Cam/tflmicro
mkdir build 
cd build 
cmake ..

make

Then you will create some files under RPI-Pico-Cam/tflmicro/build/examples/person_detection path

Test Person Detection

• Hardware connection

• Load and run person_detection The simplest method to load software onto a RP2040-based board is by mounting it as a USB Mass Storage Device. Doing this allows you to drag a file onto the board to program the flash. Go ahead and connect the Raspberry Pi Pico to your Raspberry Pi using a micro-USB cable, making sure that you hold down the BOOTSEL button to force it into USB Mass Storage Mode. 

If you are logged in via ssh for example, you may have to mount the mass storage device manually:

$ dmesg | tail
[ 371.973555] sd 0:0:0:0: [sda] Attached SCSI removable disk
$ sudo mkdir -p /mnt/pico
$ sudo mount /dev/sda1 /mnt/pico

If you can see the files in /mnt/pico then the USB Mass Storage Device has been mounted correctly:

$ ls /mnt/pico/
INDEX.HTM INFO_UF2.TXT

Copy your person_detection_int8.uf2 onto RP2040:

sudo cp examples/person_detection/person_detection_int8.uf2 /mnt/pico
sudo sync

View output

The person detection example outputs some information through usb, you can use minicom to view:

minicom -b 115200 -o -D /dev/ttyACM0

This person detection example also outputs image data and person detection results to the UART, and we provide a processing program to display them:

Learn More

• The TensorFlow website has information on training, tutorials, and other resources.
• The TinyML Book is a guide to using TensorFlow Lite Micro across a variety of different systems.
• TensorFlowLite Micro: Embedded Machine Learning on TinyML Systems has more details on the design and implementation of the framework.
• Visit, star, or fork Arducam Pico Cam GitHub Repo.

What’s your take on this? Leave your comments below!