Circuit Break - A MacroFab Podcast

MEP EP#338: Feature Complete or Minimal Viable ProductsProject DiffProbe

Landed on the topology Stephen wants

High voltage dividers

Compensation capacitors
CMRR calibration (120dB rejection)
Offset correction

Buffers and Instrumentation Amplifiers
Differential Stage
10x and 100x attenuation means offsets have to be bang on

Opamps (3 of them)

Buffers

Low input bias current
Low offset
Bandwidth?

Differential amp

Low offset. Capable of driving 50 ohm load to the scope

Gain setting resistors

Vishay ACAS 0612 - Precision resistor network
4x0603 resistors to make a diff amplifier with a gain of 2
Relative tolerance of 0.05%
Worst case relative temp-coefficient 15ppm

Project Snackey

Firmware is “feature complete”
Display Commands
How the vending motors actually work

INA219 Current Sensor
Interrupts
Improved method for next revision?

The one byte Serial Buffer problem

NEOPIXEL (WS2812) vs APA102 (SK9822)
Blocking functions
DMA - Direct memory access
Importance of full system integration testing

Timer Lockouts for motors

Is there a better way?

Show Notes

MEP EP#338: Feature Complete or Minimal Viable Products

Project DiffProbe

  • Landed on the topology Stephen wants
    • High voltage dividers
      • Compensation capacitors
      • CMRR calibration (120dB rejection)
      • Offset correction
    • Buffers and Instrumentation Amplifiers
    • Differential Stage
    • 10x and 100x attenuation means offsets have to be bang on
  • Opamps (3 of them)
    • Buffers
      • Low input bias current
      • Low offset
      • Bandwidth?
    • Differential amp
      • Low offset. Capable of driving 50 ohm load to the scope
    • Gain setting resistors
      • Vishay ACAS 0612 - Precision resistor network
      • 4x0603 resistors to make a diff amplifier with a gain of 2
      • Relative tolerance of 0.05%
      • Worst case relative temp-coefficient 15ppm

Project Snackey

  • Firmware is “feature complete”
  • Display Commands
  • How the vending motors actually work
    • INA219 Current Sensor
    • Interrupts
    • Improved method for next revision?
  • The one byte Serial Buffer problem
    • NEOPIXEL (WS2812) vs APA102 (SK9822)
    • Blocking functions
    • DMA - Direct memory access
    • Importance of full system integration testing
  • Timer Lockouts for motors
    • Is there a better way?

Creators & Guests

Host
Parker Dillmann
A Founder @MacroFab.Builds Electronics, Cars, & Jeeps.
Host
Stephen Kraig
EE
Producer
Chris Martin

What is Circuit Break - A MacroFab Podcast?

Dive into the electrifying world of electrical engineering with Circuit Break, a MacroFab podcast hosted by Parker Dillmann and Stephen Kraig. This dynamic duo, armed with practical experience and a palpable passion for tech, explores the latest innovations, industry news, and practical challenges in the field. From DIY project hurdles to deep dives with industry experts, Parker and Stephen's real-world insights provide an engaging learning experience that bridges theory and practice for engineers at any stage of their career.

Whether you're a student eager to grasp what the job market seeks, or an engineer keen to stay ahead in the fast-paced tech world, Circuit Break is your go-to. The hosts, alongside a vibrant community of engineers, makers, and leaders, dissect product evolutions, demystify the journey of tech from lab to market, and reverse engineer the processes behind groundbreaking advancements. Their candid discussions not only enlighten but also inspire listeners to explore the limitless possibilities within electrical engineering.

Presented by MacroFab, a leader in electronics manufacturing services, Circuit Break connects listeners directly to the forefront of PCB design, assembly, and innovation. MacroFab's platform exemplifies the seamless integration of design and manufacturing, catering to a broad audience from hobbyists to professionals.

About the hosts: Parker, an expert in Embedded System Design and DSP, and Stephen, an aficionado of audio electronics and brewing tech, bring a wealth of knowledge and a unique perspective to the show. Their backgrounds in engineering and hands-on projects make each episode a blend of expertise, enthusiasm, and practical advice.

Join the conversation and community at our online engineering forum, where we delve deeper into each episode's content, gather your feedback, and explore the topics you're curious about. Subscribe to Circuit Break on your favorite podcast platform and become part of our journey through the fascinating world of electrical engineering.