Robotics Development Framework

This platform has been created to allow modular development and experimentation of robotics in python / C++ using the Raspberry Pi and Arduino.

Coral TPU Accelerator

To use the Googla Coral USB Accelerator, first flash the Pi SD card with the image found in the AIY Maker Kit (Download as of 2022-08-05)

(I attempted to install the required software from the coral getting started guide but I was unable to get past an error relating to grpico "GLIBC_2.29' not found")

Alternatively, set Config.vision.tech to opencv for the original (slower) facial recognition. I am not updating this anymore so you may find some integration issues.

Installation

chmod 777 install.sh
./install.sh

Disable audio (see Neopixels section below)

Running

./startup.sh

To execute manual control via keyboard:

./manual_startup.sh

To execute startup including a preview of the video feed (not available via SSH):

./preview_startup.sh

###Testing

python3 -m pytest --cov=modules --cov-report term-missing

Run on Startup

Execute sudo vim /etc/rc/local and add the following lines before the exit 0 statement:

python3 /home/archie/companion-robot/shutdown_pi.py
/home/archie/companion-robot/startup.sh

Auto shutdown

GPIO 26 is wired to allow shutdown when brought to ground via a switch.

The script shutdown_pi.py manages this.

Guide: https://howchoo.com/g/mwnlytk3zmm/how-to-add-a-power-button-to-your-raspberry-pi

Features

Facial detection and tracking

Using the Raspberry Pi camera

Servo control

Control of up to 9 servos via an arduino serial connection

Battery monitor

Both external and software integrated via the arduino serial connection

Buzzer

A buzzer is connected to GPIO 27 to allow for tones to be played in absence of audio output (see Neopixel below). https://github.com/gumslone/raspi_buzzer_player.git

Motion Sensor

An RCWL-0516 microwave radar sensor is equipped on GPIO 13

Stereo MEMS Mics

GPIO 18, 19 and 20 allow stereo MEMS microphones as audio input

Mic 3V to Pi 3.3V
Mic GND to Pi GND
Mic SEL to Pi GND (this is used for channel selection, connect to either 3.3V or GND)
Mic BCLK to BCM 18 (pin 12)
Mic DOUT to BCM 20 (pin 38)
Mic LRCL to BCM 19 (pin 35)

https://learn.adafruit.com/adafruit-i2s-mems-microphone-breakout/raspberry-pi-wiring-test

cd ~
sudo pip3 install --upgrade adafruit-python-shell
wget https://raw.githubusercontent.com/adafruit/Raspberry-Pi-Installer-Scripts/master/i2smic.py
sudo python3 i2smic.py

####Test arecord -l arecord -D plughw:0 -c2 -r 48000 -f S32_LE -t wav -V stereo -v file_stereo.wav

Note: See below for additional configuration to support voice recognition

Speech Recognition

Trigger word for voice recognition (currently not used): https://snowboy.kitt.ai/

Speech recognition is enabled whenever a face is visible. Ensure that the device_index specified in modules/speechinput.py matches your microphone.

See scripts/speech.py to list input devices and test. See below for MEMS microphone configuration

MEMS Microphone configuration for speech recognition

By default the Adafruit I2S MEMS Microphone Breakout does not work with speech recognition.

To support voice recognition on the MEMS microphone(s) the following configuration changes are needed.

sudo apt-get install ladspa-sdk

Create /etc/asound.conf with the following content:

pcm.pluglp {
    type ladspa
    slave.pcm "plughw:0"
    path "/usr/lib/ladspa"
    capture_plugins [
   {   
      label hpf
      id 1042
   }
        {
                label amp_mono
                id 1048
                input {
                    controls [ 30 ]
                }
        }
    ]
}

pcm.lp {
    type plug
    slave.pcm pluglp
}

This enables the device 'lp' to be referenced in voice recognition. Shown with index 18 in the example below.

Sample rate should also be set to 16000

mic = sr.Microphone(device_index=18, sample_rate=16000)

References:

• MEMS Microphone Installation Guide

• Adafruit Support discussing issue

• Referenced documentation of fix

Serial communication with Arduino

In order to use the Raspberry Pi’s serial port, we need to disable getty (the program that displays login screen)

sudo raspi-config -> Interfacing Options -> Serial -> "Would you like a login shell to be accessible over serial" = 'No'. Restart

Connection via serial pins

Connect the Pi GPIO 14 & 15 (tx & rx) to the arduino tx & rx (tx -> rx in both directions!) via a logic level shifter, as the Pi is 3v3 and the arduino is (most likely) 5v.

####Upload to Arduino over serial pins To upload over serial pins, press the reset button on the Arduino at the point that the IDE starts 'uploading' (after compile), otherwise a sync error will display.

Neopixel

WS1820B support is included via the Pi GPIO pin 12. Unfortunately to support this you must disable audio on the Pi.

sudo vim /boot/config.txt
#dtparam=audio=on

This is also why the application must be executed with sudo

https://learn.adafruit.com/neopixels-on-raspberry-pi/python-usage

PCBs

Prefabricated PCBs are available for this project in the circuits folder. This allows the connection between the core components as described above.