Electric vehicle charging and cat safety

Circuit Break Podcast #162

Electric Vehicle Charging and Cat Safety

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March 6, 2019, Episode #162

Christopher Howell of OpenEVSE discusses open source electric vehicle charging stations and J1772.

Christopher Howell

  • OpenEVSE started in February 2011 with a simple experiment to try to generate the J1772 pilot signal on an Arduino
  • One experiment lead to another to another until a prototype J1772 compatible controller was born
  • With lots of feedback and interest a few boards were offered to other hardware hackers
  • What started as 6 boards built in the first batch turned into many thousands…
  • Today, OpenEVSE powers charging stations from many manufactures all over the world.


  • What is OpenEVSE? Does EVSE stand for something?
  • What is the story behind you getting into Electric Vehicle Chargers?
  •  Design
    • Generating the SAE J1772 pilot signal from an Arduino. Why Arduino?
    • What kind of regulations do you have to deal with?
    • What approvals or markings does your product have?
    • Are the kits approved?
  • Kits
    • Have you seen much interest in these? I would think most people just want a working final product.
    • Safety concerns?
  • Compatibility with vehicles?
  • Going the other way? Battery management?
  • John Cutler from twitter asks:
    • Allowing load sharing for multiple EVSEs sharing a circuit and/or supporting the Hydra style setup?
      • Day based scheduling (i.e. weekdays vs weekends).
      • Smaller, more portable and/or inexpensive models?
      • RaspberryPi based versions?
  • Guy Thomas grtyvr from our Slack Channel asks:
    • What is the current state of vehicle charging grid? And what can we do to influence decision makers to move faster on adoption?
    • Super-capacitors for buses/trains:  is there progress in that area?
    • Inductive charging for the bus/trains.  Is that a thing?
  • Which EV do you drive? Which do you recommend?
  • Github Repo


KiCon 2019 is a user conference for the popular open source CAD program KiCad. Happening April 26th and 27th 2019 in Chicago IL, this is the first and largest gathering of hardware developers using KiCad. Talks at the conference will span hardware design, revision control, scripting, manufacturing considerations, proper library management and getting  started developing the underlying tools. All announced talks have been listed on the conference site.

MacroFab will be at SXSW. We are teaming up with Particle.io to put together a Hardware Happy Hour. It will take place this Friday March 8th from 4PM until 8PM at the Jester King Brewery. Join us for food and beer and network with fellow Hardware Engineers to kick off your SXSW weekend.

Visit our Public Slack Channel and join the conversation in between episodes!

Christopher Howell of OpenEVSE recording the podcast! An OpenEVSE charger is on the wall behind him.

Christopher Howell of OpenEVSE recording the podcast! An OpenEVSE charger is on the wall behind him.

About the Hosts

Parker Dillmann
  Parker Dillmann

Parker is an Electrical Engineer with backgrounds in Embedded System Design and Digital Signal Processing. He got his start in 2005 by hacking Nintendo consoles into portable gaming units. The following year he designed and produced an Atari 2600 video mod to allow the Atari to display a crisp, RF fuzz free picture on newer TVs. Over a thousand Atari video mods where produced by Parker from 2006 to 2011 and the mod is still made by other enthusiasts in the Atari community.

In 2006, Parker enrolled at The University of Texas at Austin as a Petroleum Engineer. After realizing electronics was his passion he switched majors in 2007 to Electrical and Computer Engineering. Following his previous background in making the Atari 2600 video mod, Parker decided to take more board layout classes and circuit design classes. Other areas of study include robotics, microcontroller theory and design, FPGA development with VHDL and Verilog, and image and signal processing with DSPs. In 2010, Parker won a Ti sponsored Launchpad programming and design contest that was held by the IEEE CS chapter at the University. Parker graduated with a BS in Electrical and Computer Engineering in the Spring of 2012.

In the Summer of 2012, Parker was hired on as an Electrical Engineer at Dynamic Perception to design and prototype new electronic products. Here, Parker learned about full product development cycles and honed his board layout skills. Seeing the difficulties in managing operations and FCC/CE compliance testing, Parker thought there had to be a better way for small electronic companies to get their product out in customer's hands.

Parker also runs the blog, longhornengineer.com, where he posts his personal projects, technical guides, and appnotes about board layout design and components.

Stephen Kraig
  Stephen Kraig

Stephen Kraig is a component engineer working in the aerospace industry. He has applied his electrical engineering knowledge in a variety of contexts previously, including oil and gas, contract manufacturing, audio electronic repair, and synthesizer design. A graduate of Texas A&M, Stephen has lived his adult life in the Houston, TX, and Denver, CO, areas.

Stephen has never said no to a project. From building guitar amps (starting when he was 17) to designing and building his own CNC table to fine-tuning the mineral composition of the water he uses to brew beer, he thrives on testing, experimentation, and problem-solving. Tune into the podcast to learn more about the wacky stuff Stephen gets up to.

Special thanks to whixr over at Tymkrs for the intro and outro!