To make the SUSI Smart Speaker more interactive and to improve the visual aesthetics, we configured SUSI Smart Speaker’s response with 3 RGB led lights. We have used a new piHat as an external hardware to configure the LEDs.
Now the new hardware specs of the SUSI Smart Speaker are:
- Raspberry Pi
- ReSpeaker PiHat 2 Mic Array
- External Speakers
Using an external PiHat not only added the RGB light functionality but also eliminated the need to use a USB microphone and configured a factory reset button
Configuring the PiHat as the default Audio driver
To Use the PiHat as the default input driver, we use the package called PulseAudio.
And we use the following command in the installation script.
| pacmd set-sink-port alsa_output.platform-soc_sound.analog-stereo analog-output-headphones |
Configuring PiHat’s GPIO Button with Factory Reset
There is an onboard User Button, which is connected to GPIO17. We use the python library RPi.GPIO to detect the user button. The python script is used in the following way
| GPIO.setmode(GPIO.BCM) GPIO.setup(17,GPIO.IN) i = 1 while True: if GPIO.input(17) == 1: time.sleep(0.1) pass elif GPIO.input(17) == 0 : start = time.time() while GPIO.input(17) == 0 : time.sleep(0.1) end = time.time() total = end – start if total >= 7 : subprocess.call([‘bash’,‘factory_reset.sh’]) # nosec #pylint-disable type: ignore else : mixer = alsaaudio.Mixer() value = mixer.getvolume()[0] if value != 0: mixer.setvolume(0) else: mixer.setvolume(50) print(total) time.sleep(0.1) |
This script checks on the button which is configured on GPIO port 17 on the PiHat. If the button is pressed for than 7 secs, the factory reset process takes place, else the device is muted.
Configuring PiHat’s LED with Speaker’s Response
We use a python library called SPIDEV to sync the LED lights with SUSI’s response. SPIDEV is usually used to send a response to the bus devices on the Raspberry Pi.
The first step was installing spidev
| sudo pip install spidev |
Now we create a class where we store all the methods where we send the signal to the bus port. We treat the LED lights as a circular array and then have a rotation of RGB lights
| class LED_COLOR: # Constants MAX_BRIGHTNESS = 0b11111 LED_START = 0b11100000 def __init__(self, num_led, global_brightness=MAX_BRIGHTNESS, order=‘rgb’, bus=0, device=1, max_speed_hz=8000000): self.num_led = num_led order = order.lower() self.rgb = RGB_MAP.get(order, RGB_MAP[‘rgb’]) if global_brightness > self.MAX_BRIGHTNESS: self.global_brightness = self.MAX_BRIGHTNESS else: self.global_brightness = global_brightness self.leds = [self.LED_START, 0, 0, 0] * self.num_led self.spi = spidev.SpiDev() self.spi.open(bus, device) if max_speed_hz: self.spi.max_speed_hz = max_speed_hz def clear_strip(self): for led in range(self.num_led): self.set_pixel(led, 0, 0, 0) self.show() def set_pixel(self, led_num, red, green, blue, bright_percent=100): if led_num < 0: return if led_num >= self.num_led: return brightness = int(ceil(bright_percent * self.global_brightness / 100.0)) ledstart = (brightness & 0b00011111) | self.LED_START start_index = 4 * led_num self.leds[start_index] = ledstart self.leds[start_index + self.rgb[0]] = red self.leds[start_index + self.rgb[1]] = green self.leds[start_index + self.rgb[2]] = blue def set_pixel_rgb(self, led_num, rgb_color, bright_percent=100): self.set_pixel(led_num, (rgb_color & 0xFF0000) >> 16, (rgb_color & 0x00FF00) >> 8, rgb_color & 0x0000FF, bright_percent) def rotate(self, positions=1): cutoff = 4 * (positions % self.num_led) self.leds = self.leds[cutoff:] + self.leds[:cutoff] def show(self): data = list(self.leds) while data: self.spi.xfer2(data[:32]) data = data[32:] self.clock_end_frame() def cleanup(self): self.spi.close() # Close SPI port def wheel(self, wheel_pos): “””Get a color from a color wheel; Green -> Red -> Blue -> Green””” if wheel_pos > 255: wheel_pos = 255 # Safeguard if wheel_pos < 85: # Green -> Red return self.combine_color(wheel_pos * 3, 255 – wheel_pos * 3, 0) if wheel_pos < 170: # Red -> Blue wheel_pos -= 85 return self.combine_color(255 – wheel_pos * 3, 0, wheel_pos * 3) wheel_pos -= 170 return self.combine_color(0, wheel_pos * 3, 255 – wheel_pos * 3)
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Now we use the threading to create non-blocking code which will allow SUSI to send response as well as change the LED’s simultaneously.
| class Lights: LIGHTS_N = 3 def __init__(self): self.next = threading.Event() self.queue = Queue.Queue() self.thread = threading.Thread(target=self._run) self.thread.daemon = True self.thread.start() def wakeup(self, direction=0): def f(): self._wakeup(direction) self.next.set() self.queue.put(f) def listen(self): self.next.set() self.queue.put(self._listen) def think(self): self.next.set() self.queue.put(self._think) def speak(self): self.next.set() self.queue.put(self._speak) def off(self): self.next.set() self.queue.put(self._off) |
This is how LED lights are configured with SUSI’s response
Resources
- http://wiki.seeedstudio.com/ReSpeaker_2_Mics_Pi_HAT/
- https://pypi.org/project/spidev/
- https://github.com/fossasia/susi_linux
Additional Resources
- More about the APA LEDs (the ones being used in the piHat): https://cpldcpu.wordpress.com/2014/08/27/apa102/
- More about PulseAudio: https://www.freedesktop.org/wiki/Software/PulseAudio/
- Threading used extensively in the above program: https://docs.python.org/3/library/threading.html