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The Yorick Project

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I like to decorate for Halloween, including various talking skeletons that I’ve set up over the years. For Christmas 2015, my wife gave me a great 3 axis talking skull with moving eyes so I could upgrade one of the skeletons from just a moving jaw skull. Then a friend suggested that there had to be other applications for the rest of the year. This got me thinking, and when I saw the Alexa Billy Bass I knew what I had to do, and the Yorick project was born. I’m pretty happy with the result:

Now, if you put this project together from scratch, it’s pretty expensive, due to the cost of the 3-axis talking skull, but if you are looking to re-purpose one you have, or a similar device, then you may want to develop a similar project. The key elements are the talking skull, a Raspberry Pi and the AlexaPi software for turning the Pi into an Alexa client device, the audio servo controller for turning the output sound into servo commands for the jaw, and the servo controller for controlling the nod, turn, tilt, and eye servos of the skull.

Block diagram for Yorick

Bench testing the set-up

The AlexaPi software provides output to two GPIO pins, intended to light up LEDs as the Pi hears the wakeup word, listens to the input, gets the response from the Amazon Alexa service, and then speaks the response. All the directions for AlexaPi are on the creator’s GitHub site. For this project, we also linked the same pins to input pins on the Maestro servocontroller. The Maestro I used allows pins to be used as output (primarily for servos, but also for other purposes) or as analog inputs. Other models also have digital input pins. By reading the status of the input pins, we know which state to be in, as there is a separate routine of head motions for inactive, wake, listen, get response, and speak response.

The servo sequences are developed using the GUI-based controller software provided by Pololu, and then custom control commands are added using their stack-based scripting language. The partial script is included at the end of the article. The short first section that is provided is the control code I wrote, the rest (not shown) are the automatically generated subroutines based on the sequences I defined using their GUI driven software.

The skull motions for each state are predefined and fixed (the routines are looped as needed for the typically longer lasting states (get response and speak response). The one key tip is to slow down the servos in order to look more realistic. The Maestro controller software lets you limit the speed and acceleration of each servo, and with the exception of the jaw servo, which had to have quick response to changing audio, I set both the speed and acceleration values to 20.

The audio servo driver board converts the audio put out by the Pi into servo commands for the jaw, while also passing the audio through to the powered speakers. Others have developed their own software do drive motor (rather than servo) based devices such as Billy Bass and Teddy Ruxpin, based on the amplitude of the sound. I’m sure the same could be done to drive the jaw servo by extracting the volume of the sound, but I already had an audio servo driver board that is otherwise unused except for Halloween, so I used that. (Update: I’ve since developed my own Raspberry Pi based audio servo controller and there’s also the Jawsduino project that uses an Arduino.)

3-axis talking skull with moving eyes

Raspberry Pi with Kinobo USB microphone

Audio servo controller board

Mini Maestro Servo Controller board

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I put it all in a project box, and covered the threaded rod supporting the skull with a short length of PVC pipe, painted black, to produce the final result:

Rather messy (mainly with the 5 servo cables), but it all fits in the box.

Hardware Components

  • 3-axis talking skull with moving eyes. Mine is from audioservocontroller.com
  • Powered speakers – The Raspberry Pi puts out very little volume from the audio jack, so you want amplified speakers, whether battery powered or from line current. I used an old pair of inexpensive computer speakers
  • Raspberry Pi 3 – Other models with WiFi should also work
  • Kinobo – USB 2.0 Mini Microphone – You need a microphone for input, and I was quite happy with the performance of this one, considering it only cost $5.25!
  • Pololu Mini Maestro Servo Controller – I used the 12 channel version, larger versions should also work.
  • Audio servo driver board – I used an ST-200 board from Cowlacious that I had for a Halloween project. That model has been replaced by the newer and improved ST-400 model, which should work fine. audioservocontroller.com also sells a similar board
  • Misc., including project box, LEDs (optional), resistors (optional, if LEDs used), breadboard (optional, if LEDs used), PVC pipe, and jumper wires.

Software Components

  • AlexaPi open source client software for Amazon’s Alexa service
  • Pololu’s Maestro Controller Software – I used the Windows version, but they have versions for Linux as well.
  • Custom script for the Maestro servo controller to control the skull. An excerpt to give you a feel for the scripting language is posted below. The full script I used is posted as a gist on Git Hub: https://gist.github.com/ViennaMike/b714fc2c9b7eaaaaff952175536a4942

 

begin     # Loop until input 9 goes high
  9 get_position # get the value of the red trigger, 0-255
  155 greater_than # test whether it is greater than 155 
  if      # Wakeup word detected, run wake movement sequence
    wake     
    750 delay
    1 # flag for getting out of loop
    begin
      dup
      while
      9 get_position
      10 get_position
      plus
      300 greater_than
      if     # If after wake, both inputs high, then getting reply
        think
      else
        9 get_position
        155 greater_than
        if     # if just input on 9 high, then speaking reply
          answer
        else
          10 get_position
          155 greater_than
          if   # if just input on 10 high, then listening to query
            listen
          else     # when both inputs at zero, back to rest mode
	    Rest
            1 minus
          endif
        endif
      endif 
    repeat
  endif
repeat

### Sequence subroutines: ###
# Sequence subroutines removed not included for brevity

National Maker Faire 2016

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I attended the National Maker Faire held over Father’s Day weekend at the University of the District of Columbia, and thought I’d share some observations and pictures. They’ve added the National Maker Faire to the list of flagship faires around the US, along with the original Bay Area and World Maker Faires. I’ve been to the World Maker Faire once, and from that and what I’ve heard of the Bay Area Faire, the National Faire is much smaller than either. You could certainly see it all in less than half a day. It’s also a bit random in its layout, as it makes use of several areas of campus buildings and grounds. Unlike the other two major faires, I would not travel from out of town to see this one. But for anyone on the greater DC area, I found it well worth my time.

It’s not new, but I hadn’t seen the Intel Arduino 101 board before. I’d have loved if it had WiFi but the built in real-time clock, bluetooth, accelerometer, and gyro make it quite interesting. Apparently the Curie system on a chip module it’s build around also has a 128-node neural network for machine-learning, but there is, at least as of now, no software released to access it.

Ability3D had a table promoting their planned 3d metal printer, with a kickstarter campaign planned for January 2017. They were showing a development prototype model (the final consumer product to be smaller). It prints with powdered metal. I believe they said they were targeting the several thousand dollar range for price, so not inexpensive for a home printer, but an order of magnitude cheaper than current metal powder printers.
Nova Labs, one of the local area makerspaces, was also there with some interesting demos and projects.

There was also a lock picking village put on by TOOOL, which was quite full when I went by. It was also nice to see a short waiting line for the “Learn to Solder” hands on booth. How often do you see people lining up to learn to solder? Unfortunately for some reason the drones only were being flown on Saturday, and there were no drone demos when I went on Sunday.

Below are a number of photos from the event:

Learn to Solder hands on exhibit

Learn to Solder hands on exhibit

Ability3D's booth. Developing a home metal powder 3D printer

Ability3D’s booth. Developing a home metal powder 3D printer

Cardboard pinball kits, with options to add arduino, electronics, servo, etc. There's going to be an upcoming kickstarter campaign.

Cardboard pinball kits, with options to add arduino, electronics, servo, etc. There’s going to be an upcoming kickstarter campaign.

Why Everyone Should Care About Strong Encryption

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One often hears statements along the lines of “I have nothing to hide, why should I care about encryption, government access, etc.” The fact is, though, that most of us either directly access services over the internet or do business with companies that store data on computers. And even if you fully trust your government, you certainly don’t trust criminals who want to break in and steal your data, your money or your identify. Strong encryption is essential for protecting this data. I suspect this may be obvious to any regular readers of this blog, but this may provide some useful information for discussion with your friends and colleagues who don’t think they have a stake in the game.

I”ll use password protection as an example. Anyone doing any sort of business or information sharing online uses passwords. Using weak passwords and/or reusing the same few at many sites is a very bad practice that leads to ID theft and hacked bank accounts. But it’s difficult or not impossible to remember dozens and dozens of strong random passwords. That’s why many of us use an online password manager that we trust (I happen to use LastPass, but there are several good ones).

A key element in trusting them is that, at LastPass puts it: “The user’s master password, and the keys used to encrypt and decrypt user data, are never sent to LastPass’ servers, and are never accessible by LastPass.” Only highly encrypted versions of my passwords go to LastPass, and my master password never does. So whether a hacker or the government breaks into LastPass, all they get is the encrypted data.

Even if you don’t use a password service, it’s basic good security practice for the companies you do business with to NOT store your password anywhere, but rather a secure hash of the password. This allows them to verify that YOU have correctly entered your password without actually knowing the password, but rather knowing a value that was algorithmicly derived from your password but that cannot reasonably be reverse-engineered to determine your password. If they don’t know your password, then it can’t be stolen from them.

Bills like Burr-Feinstein  propose to outlaw such services! The Senate bill, and similar proposals, would require that a company be able to decrypt the data they store for you, outlawing secure mechanisms that protect your data by never getting your unencrypted data AND never knowing your decryption key. Instead, weaker services that are vulnerable to hacks would be all that would be legally available.

You may not be a dissident or an investigative journalist, but you likely have bank and credit card accounts you’d like to keep as safe as possible. You need strong encryption.