Chris Svec of iRobot and Phillip Johnston of Embedded Artistry join Christopher and Elecia to talk about the hows and whys of estimating software schedules.. The article that started the discussion was Agile Otter’s Platitudes of Doom.  You can participate in these sorts of discussions on the Embedded Slack Channel by supporting Embedded on Patreon.  On Phillip’s Embedded Artistry Website you can find a library of courses, hundreds of free articles, and even more member's only content. Their current focus is developing two new courses: Designing Embedded Software for Change and Abstractions and Interfaces. There are also many great posts on planning and estimation.

Matthew Liberty shared good advice for lowering power. We talk about different ways to measure current (Matt has a nice write-up) and things software can do to decrease power consumption. Sleeping is critical, of course, as is choosing your clock speed and setting the GPIOs to good states. Everything is fine until you start getting into the microamps, then your multimeter measurements may start to fail you. (EEvblog explains why in his uCurrent intro.) Eventually, you may want to measure nanoamp sleep states along with amp-consuming wake states. Matt’s Joulescope is a tool to do just that (Kickstarter goes live Feb 19, 2019!), automatically moving between 9 orders of magnitude of dynamic range and graphing the results on your computer. Matthew’s consulting company is JetPerch. We mentioned Colin O’Flynn’s ChipWhisperer which uses differential power analysis for security attacks. We also talked about Jacob Beningo’s post on protecting your tools. Find Matt on Twitter as @mliberty1. Elecia is giving away a chapter of her O’Reilly book, Making Embedded Systems. It is Chapter 10: Reducing Power Consumption. Hit the contact link if you want a copy.

Miro Samek joins us to discuss designing systems, state machines, and teaching courses. Miro’s company is Quantum Leaps (state-machine.com) which provides commercial licensing for QP Real-Time Embedded Frameworks.  It is an open source project, the code can be found on github: github.com/QuantumLeaps/qpc  One of the key concepts is an Active Object which aids in real-time system development, especially in the areas of state machines and concurrency.  Miro’s (amazing) Modern Embedded System Programming series can be found on his YouTube channel.  You can also find Miro on Twitter: @mirosamek

Christopher and Elecia celebrate their 400th episode by discussing what has (and hasn’t) changed in embedded systems over the last 9 years

Jen Costillo joined us to talk about voice acting, reverse engineering, podcasting, and dance. Jen’s podcast is the Unnamed Reverse Engineering Podcast, found in all your usual podcast places. Jen and her co-host Alvaro were on an episode of Opposable Thumbs podcast. Find Jen on Twitter at @RebelbotJen (also @unnamed_show and @catmachinesSF). Rebelbot.com has her blog and Cat Machines Dance is her site devoted to dance (including the mentioned video about dancers and the pandemic). The Hardware Hacking Handbook: Breaking Embedded Security with Hardware Attacks by Jasper van Woudenberg and Colin O'Flynn  Jen is studying voice-overs at VoicetraxSF  Jen has been on the show many times in the past. Some of our favorites include 108: Nebarious about security and privacy 82: I Was a Chewbacca Person about movies that influenced their path to engineering 51: There Is No Crying in Strcpy about interviewing 25: Thunderdome for Antennas about RF and manufacturing consumer products 10: Hands Off, Baby about C keywords

Tom Anderson explains radio frequency electronics (RF). Elecia and Christopher try to keep up. We also took a detour into bass guitar electronics. One confusing jargon part is that radio power (in dBm) is discussed as though it is voltage. For example, 10 dBM is 2V peak-to-peak; there is an implied 50 ohm resistor in the P=V*V/R calculation. The the wiki for more about decibel-milliwatts. Tom talked about dollhouses, aka Smith charts (wiki). (We also talked about Bode plots (wiki).) Light travels about 1 foot in 1 nanosecond (11.8 inches, 30 cm). Admiral Grace Hopper is well known for giving out nanoseconds. The guitar company Tom mentioned working with is Alembic. Find Tom’s writing on Medium and the Tempo Automation blog. He is on Twitter as @tomacorp and was previously on Embedded 379: Monstrous Cable Corporation.

We spoke with Phillip Johnston (@mbeddedartistry) of Embedded Artistry about consulting, writing, and learning. 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?

Chris and Elecia ring in the new year with a discussion of projects, hobbies, origami, DMA, music, and the new-and-improved Embedded.fm newsletter... Pepto Bismol can be converted to metal bismuth (YouTube) which can be turned into lovely sculptures. Chris liked his new book, Art of NASA: The Illustrations That Sold the Missions by Piers Bizony.  Elecia liked hers, Curved Origami: Unlocking the Secrets of Curved Folding in Easy Steps by Ekaterina Lukasheva  Guitar Fart Pedal (Kickstarter) Elecia’s Making Embedded Systems course will have a second cohort starting in March 2022.  Sign up for the newsletter if you want an announcement (at the bottom of the Embedded.fm Subscribe page).

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. 

Uri Shaked shows us Wokwi, his board and processor simulator. We checked out Arduino code in GDB and then looked at his simulator for the Cortex-M0 Raspberry Pi Pico.  First, you should totally  look at Wokwi.com. As Christopher noted, signing up for an account shows you many other things. Then you can go look at the processors written in TypeScript in Uri’s Github repos: github.com/urish. Find Wokwi on Twitter (@WokwiMakes, Uri is @UriShaked). You can also find Wokwi on Facebook. Uri live-coded development of the Pico’s RP2040, it is on Wokwi’s YouTube channel. You can find out more about the RP2040 or the AVR core in the ATMega family by taking his free courses on Hackaday: hackaday.io/urishaked  (Scroll down for courses.) Uri’s homepage is urish.org. You can find The Salsa Beat Machine there as well as some of his other projects. He has a blog there as well as at Wokwi. Susie Hansen - La Salsa Nunca Se Acaba