This week we talk about CircuitPython (@CircuitPython) with @adafruit’s Kattni Rembor (@kattni) and Scott Shawcroft (@tannewt).  The suggested first board is CircuitPlayground Express with LEDs, sensors, and buttons. CircuitPython is also available for many other boards including the BLE Feather (NRF52832). For a basic introduction take a look at What is CircuitPython and see some example scripts. To dig a little deeper, check out the many resources in Awesome CircuitPython. The whole thing is open source so you can see their code. If you are thinking about contributing (or just want some fun chats), get in touch on the CircuitPython channel of the Adafruit Discord server: adafru.it/discord Many of the language’s design choices favor ease-of-use over ready-for-production. Imagine teaching an intro to programming class without worrying what computers will be used or how to get compilers installed on everyone’s machines before time runs out.  One final note: Kattni did a project that gave us the show title: Piano in the Key of Lime. After we finished recording, Chris asked her why she didn’t add a kiwi fruit to her mix… Kattni explained she had limes and they were small. Chris only wanted a different fruit so she could rename it Piano in the Kiwi of Lime. It is always sad when we stop recording too early.

Mike Harrison (@mikelectricstuf) challenged us to a PIC fight on Twitter. Surprisingly, no blood was shed and we mostly talked about LEDs and art installations. Mike’s YouTube Channel and his website electricstuff.co.uk His professional hire-him-to-work-on-your-neat-stuff site is whitewing.co.uk For driving LEDs, Mike likes the TI TLC5971: 12-Channel, 16-Bit ES-PWM RGB LED Driver with 3.3V Linear Regulator. Mike will be at 2019 Hackaday SuperCon!

Limor Fried of Adafruit spoke with us about engineering, education, and business.  Some new boards we talked about include the PyGamer and PyBadge (which also has a lower cost version). TinyUSB, an open and tiny USB stack from Hathach. In addition to the many excellent tutorials there are some interesting business related posts on Adafruit Learn: How to Build a Hardware Startup and How to Start a Hackerspace Want to get more involved with the extensive, wonderful, and supportive Adafruit community? Join their Discord chat server or Show and Tell on Wednesdays 7:30pm (ET) followed by Ask an Engineer at 8pm. 

Christopher (@stoneymonster) and Elecia (@logicalelegance) babble about their current projects involving ants, guitars, machine learning, and party planning. A video of Christopher’s ants Some tweet threads about our tour of Santa Cruz Guitar Company. Arrival (also: very old wood) Wood is awesome Adding science to precision craft Elecia has been reading  Hands-On Machine Learning with Scikit-Learn, Keras, and TensorFlow by Aurélien Géron. While the 2nd edition preview is on O’Reilly’s electronic library (formerly Safari Online), it will be available via Amazon on July 5th. Or pick up the first edition. Phillip Johnston of Embedded Artistry (290: Rule of Thumbs) is looking for blog posts, exchanging editing and exposure for posts that make sense on the site. Contact him with a topic idea before jumping in. For the Embedded blog, related to the show with Phillip, Elecia wrote a post about learning to give feedback. Listener Brian asked about a CS degree for going into firmware. We mentioned our show with Dennis Jackson (211: 4 Weeks, 3 Days). Listener Craig asked about PICs. We suggested taking a look at Jay Carlson’s Amazing $1 Microcontroller. We talked to Jay in 226: Camp AVR vs. Camp Microchip. Listener Happyday asked about UL testing. We added FCC testing then asked if any of you could help us. Hit the contact link on Embedded.fm. Embedded has a Patreon. There are new sponsorship levels! Nothing has changed though.

Karl Auerbach of InterWorking Labs spoke with us about how the internet works. We talked about domain name services (DNS being the primary one), registries and registrars, domain thieves, and the History of the Internet project. Karl runs his own (non-DNS) domain name service on his site www.cavebear.com. The site also includes notes from his time on the ICANN board (such as this one where they talk about redemption periods).

We spoke with Phillip Johnston (@mbeddedartistry) of Embedded Artistry about embedded consulting, writing about software, and ways to improve development. In the Embedded Artistry welcome page, there is a list of Phillip’s favorite articles as well as his most popular articles. Some of Phillip’s favorites include: Embedded Rules of Thumb Improving SW with 5 LW Processes Learning from the Boeing 737 MAX saga We also talked about code reviews and some best practices. The Embedded Artistry newsletter is a good way to keep up with embedded topics. You can subscribe to it at embeddedartistry.com/newsletter What are condition variables?

Alicia Gibb (@pipix) joined Elecia to talk about open source hardware, the OSHW association (@ohsummit), using trademarks for quality control, and light-up LEGO blocks. Alicia is the editor and author of Building Open Source Hardware: DIY Manufacturing for Hackers and Makers. It is a handy resource for any manufacturing. Alicia is the director of the Blow Things Up Lab, part of the Atlas Institute at the University of Colorado Boulder. Light up LEGO blocks are available at Build Upons. The LilyPad Arduino has many sewable electronics components. You can find more talks and hacks on Alicia’s personal site, aliciagibb.com.

Christopher (@stoneymonster) and Elecia (@logicalelegance) discuss embedded systems education and project documentation. Elecia wrote about her love of notebooks on the https://www.embedded.fm/blog-index. yEd, for when you don’t have Visio. Asciiflow.com, for when you don’t have yEd (or you want to put diagrams in your comments) We talked about many different documents and tried to note design vs implementation, product vs engineering vs user, and why we wanted them. We didn’t mention mechanical things because, ya know, software engineers. Some documentation we mentioned: Product documentation Schematics with block diagrams and comments. Also a GPIO to function spreadsheet. UI flow when the system has a screens (Balsamiq for wireframe testing UIs) SW spec and design doc: what do we plan to build and what are the tricky parts SW configuration and SW developer docs: how to rebuild the computer that can build the code from scratch, also notes on debugging methodology User manual: Usually not written by SW but may need SW’s patient input Code comments: Functions and files get 5Ws: who, what, why, when, where, and how. Who should call this? What will its effect be? (“What will it do” but not in line by line detail!) How does it work? Why does it work this way? When should it be called? Where are its parameters? (“What” works here too but “where” is nice to remind you to check your memory assumptions.) Repository checkin comments Style guide (Such as Google’s or PEP) Manufacturing docs and tests docs   Adafruit and Sparkfun both write good documentation, writing to users about how to use their code. Elecia likes Adafruit’s sensor library as a good set of code to review (including how much is in their docs vs their code).

Crossing machine intelligence, robotics, and medicine, Patrick Pilarski (@patrickpilarski) is working on smart prosthetic limbs. Build your own learning robot references: Weka Data Mining Software in Java for getting to know your data, OpenIA Gym for understanding reinforcement learning algorithms, Robotis Servos for the robot (AX is the lower priced line), and five lines of code: Patrick even made us a file (with comments and everything!). Once done, you can enter the Cybathlon. (Or check out a look at Cybathlon 2016 coverage.) Machine Man by Max Barry Snow Country by Bokushi Suzuki Aimee Mullins and her many amazing legs (TED Talk) Patrick is a professor at University of Alberta, though a lot more than that: he is the Canada Research Chair in Machine Intelligence for Rehabilitation at the University of Alberta, and Assistant Professor in the Division of Physical Medicine and Rehabilitation, and a principal investigator with both the Alberta Machine Intelligence Institute  (Amii) and the Reinforcement Learning and Artificial Intelligence Laboratory (RLAI). See his TED talk: Intelligent Artificial Limbs.

Kate Compton (@GalaxyKate) spoke with us about casual creators, Twitter bots done cheap and quick, and the creativity that is within each of us. Kate’s website is galaxykate.com. Her Phd dissertation defense is interesting, see it on youtube.com. She is joining UCSC’s CROSS to do more work on casual creators and open source software. (We talked to Carlos Maltzan, the head of CROSS in 285: A Chicken Getting to the Other Side.) Tracery is an open source story generator using a specific grammar. One example is at Kate’s BrightSpiral.com which creates a whole story every time you refresh. You can use Tracery to make Twitter bots via CheapBotsDoneQuick.com. They are often text (@infinite_scream, @str_voyage, @DUNSONnDRAGGAN) or emoji based (@choochoobot, @infinitedeserts). However, Tracery and CBDQ  can be used to create SVG images (such as @softlandscapes). Elecia’s text bot is @pajamaswithfeet. It tweets (usually) kind things you can (sometimes) say to other people (or yourself).