Friday, February 19, 2021

A new program for Google Voice AIY

My earlier post, about a function that could send things to the Google AIY Raspberry Pi Assistant, and supposedly prevent more than one message being spoken at a time, was errmmm, wrong. That's a technical term, that we programmers use.

I wrote a test program for my Pi cluster, whereby each of the sixteen cores would announce its hostname and rank. It's not all that often you get the opportunity to use the word cacophony, but...

Basically, several processes could all think the Assistant was not busy, and they all sent messages in the time it took for the first message to start being spoken.

I spent a while looking at how to program mutual exclusivity for a resource, and was impressed by how complex such an apparently simple thing can get.

I decided that what was needed was a simple program, running on the Assistant, that would watch a directory, notice when a file to be spoken arrived, and speak the text in that file. Python makes it easy to deal with more than one file in the directory. Here's what I wrote...

# Program to run on PiAssistant, to watch for newly arrived text files in
# /home/pi/Messages that it should speak, and delete them once it has.
import os
import time
path = "/home/pi/Messages/"
while True:
    with os.scandir(path) as entries:
        for entry in entries:
            f = open(entry, "r")
            content =
            command = "python ~/AIY-projects-python/src/aiy/voice/ \"" + \
                      content + "\" --lang en-GB --volume 10 --pitch 60 --speed 90"

When it spots one of more files in the Messages directory, it reads the text, and sends it out to be spoken. It can supposedly only do one file at a time, but... Still the cacophony!    

#RaspberryPi #GoogleAIY #Python            

Tuesday, February 16, 2021

How not to make a Twitter poll.

A Question of Saffron

Something or other reminded me recently that I can't seem to detect the smell or taste of saffron. A lot of people love it, and write passionately about it. They've smelled it being brought to them even before the waiter came through the kitchen door. They say they've had it explode in their mouth. And I have missed out... 

I wondered whether it was just me, or a fairly common thing, to be unable to smell and taste saffron, so I made a Twitter poll.

It was worded very poorly. To be fair to myself, at the time, I didn't think about it at all carefully. The result was that it didn't work the way I had expected.

A lot of people thought this was a question about whether saffron is wonderful, whether it is over-priced, or any of several possible interpretations. What I should have actually asked was "Can you smell and taste saffron". Like this...

Of course, this isn't good enough, either, as it discriminates against people who want to say that they can't afford saffron, or have never heard of it. But the worst thing is, all we can tell from the result of the original poll is that about half the people who saw the poll, and answered it,

  • like the smell of saffron

and about half of them 

  • think it is too expensive.
which actually tells us nothing at all about how many people can detect the taste and smell of saffron, and how many cannot.


Polls. We see lots of them quoted, and they are mostly about politics, and are supposed to let us know how people think about things that matter rather a lot more than whether one can detect saffron.

And a lot of those polls are even less well designed than mine. Some are even designed to make people draw the wrong conclusion, and it's not easy to tell which ones those are, is it?

Tuesday, February 02, 2021

Using Google AIY voice.

Using Google AIY voice, part 94.

I wrote a useful function, so that any of my Raspberry Pi machines could send a string to the Google Assistant as a message to be spoken aloud, and it worked very well. Here it is...

# A function to send a string to PiAssistant for output as speech
import paramiko

ssh = paramiko.SSHClient()

server, username, password = ('PiAssistant', 'pi', 'your_password-goes_here')
def say_this_with_assistant(say):
    ssh.connect(server, username=username, password=password)
    command = "python ~/AIY-projects-python/src/aiy/voice/ \"" + say + "\" --lang en-GB --volume 10 --pitch 60"

say_this_with_assistant("Normal service will be resumed as soon as possible. ")

The snag occurs when two, or more, machines want to say something at the same time. The PiAssistant calmly multitasks, and says the strings at the same time, which sounds interesting, but tends to be incomprehensible. I hoped that voice/ would have some way of letting other programs know whether it was busy, but it doesn't. However, the low level Linux ps command can tell when voice/ is running, so I added a check for that as a Paramiko command, like this...

# A function to send a string to PiAssistant for output as speech when it's free
import paramiko
import time

ssh = paramiko.SSHClient()

def say_when_free(say):
    server, username, password = ('PiAssistant', 'pi', 'your_password-goes_here')
    ssh.connect(server, username=username, password=password)    

    command = "ps -ef | grep -v grep | grep \"voice.tts\" | wc -l"
    while True:
        ssh_stdin, ssh_stdout, ssh_stderr = ssh.exec_command(command)
        answer = str(
        if answer[2] == "0":
    command = "python ~/AIY-projects-python/src/aiy/voice/ \"" + say + "\" --lang en-GB --volume 10 --pitch 60"

say_when_free("I waited until I was allowed to say this. ")

I'm not going to claim  any of this as properly written Python, the best way to do what is required, or even particularly original, but it does currently seem to be the only description of how to do this that's on the internet.

Monday, January 11, 2021

Google Assistant updates. 

Once I had my Google Assistant running Raspbian Buster, and verified that it could not only answer spoken questions, but also speak text sent to it by other computers, I made a bad mistake.

As a rule, it's a good idea to keep a Raspberry Pi's operating system up to date. Not on this system, it turns out!

I found that doing so stops the microphone working. Other people have also found this, according to the internet, dating back to 2018.

It was simple enough to fix, once I knew that the update was the cause of the trouble. I just flashed the micro SD card again, and copied my configuration files back onto it. Just like that, it was all working again. The files you need to copy back on are assistant.json client_secrets.json and credentials.json, if you were wondering.

In order not to let the same unpleasantness happen again, I disabled the update programs apt and apt-get, using the commands

sudo chmod a-x /usr/bin/apt
sudo chmod a-x /usr/bin/apt-get

Monday, December 14, 2020

Huge struggle with Google Assistant

 Google Assistant

I really like this thing, it's a Raspberry Pi 3B+, with a Google AIY Voice HAT, and a nifty acrylic case instead of the original cardboard one.

I've had it for a while though, and it was still running Raspbian Jessie. Nothing wrong with that, but there are new versions of the AIY Voice software, that can do more things than the original software. I'd rather like my other Raspberry Pi systems to be able to use it as a voice input and output, for example. To do that requires Raspbian Buster...

So that I wouldn't lose all the setup information on the Micro SD card, I decided to upgrade in place. Bad idea!

The upgrade, two steps, via Raspbian Stretch, takes hours. Stretch booted OK, though, so I continued. Buster wouldn't boot up...

All that took over half a day, and it didn't work.

After a bit of head scratching, and a certain amount of exercising my extensive vocabulary of rude words, I did what anyone sensible would have done in the first place, and downloaded a ready-made image, from GitHub and flashed the micro SD card with Balena Etcher.

I had saved copies of the setup information files handy, which I copied in with WinSCP (freeware that's so great I paid for it!), rebooted the Pi, and suddenly it worked!