Circuit Break - A MacroFab Podcast

By MacroFab, Inc.

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 p... more

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FAQs about Circuit Break - A MacroFab Podcast:

How many episodes does Circuit Break - A MacroFab Podcast have?

The podcast currently has 448 episodes available.

Circuit Break - A MacroFab Podcast episodes:

September 15, 2021MEP EP#294: Twisted Pairs
MEP EP#294: Twisted Pairs
USB vs Ethernet for Test Equipment?
Ethernet comes with free isolation

No drivers required to get Ethernet working

USB is faster to get working depending on your network hacking skills

USB software stacks in test equipment are kinda hit or miss
How to make hardware work with Ethernet?
Still learning about this

Trying out Arduino -> Ethernet shields that use the Wiznet W5100

Managed to get a demo working with SCPI and the shield
Tag Connect : Edge-Connect
https://www.tag-connect.com/product-category/products/edge-connect

Spring loaded leaf springs in a connector that slides onto the side of a PCB

Looks like a great alternative to normal tag connect
Bias test connector - OTC (one time connect)
PEM smtsss-4mm-6et solderable spring standoffs

Use in conjunction with through hole pogo pins

Just add holes and target points on main pcb and plug the connector in for access to the nets
...more
47min
September 09, 2021MEP EP#293: Tom Anderson, the Gold Ear Sympathetic
MEP EP#293: Tom Anderson, the Gold Ear Sympathetic
Tom Anderson
An old-timer engineer working from HP/Agilent/Keysight

Currently still employed at Keysight

Volunteering at Alembic, where he designs electronics for bass guitars

Career includes:
Design of firmware

Digital

Analog

Microwave

Optical

Power supplies

Software

Information systems
Metrology and You
Do I need to worry about all of this? (as a hobbyist, is accuracy important?)-

Measure with micrometer...

Taking Measurements
voltage, current, resistance, inductance, capacitance, Q, frequency, time, noise, RF/microwave

Measurement Uncertainty
+/- 0.1dB specification - what can go wrong?

How do you make things more accurate?
System engineering - when the boards are put together, does the system work?

Testing the idea that multiple resistors are tighter tolerance than single
Are the values random?

Sources of errors - narrow things down to the path between a sensor and an ADC
Temperature

Noise, thermal

Noise, switching power supply, rectifier diodes

Noise, clock, data, address

DC shift - where does the ground current flow? Screws, contact resistance, and X-Acto blades.

Offset voltage and current

Connector Repeatability

Temperature
Repeatability/Skid

Controlling temperature (room air, coffee cup, fingers, oven proportional control)
...more
1h 23min
September 01, 2021MEP EP#292: Scott Hinson of Pecan Street Inc.
MEP EP#292: Scott Hinson of Pecan Street Inc.
Scott Hinson
The Chief Technology Officer at Pecan Street

Leads the Pecan Street Lab

Directs research efforts to study the grid and climate impacts for integrating renewable technologies, electric vehicles, and software enabled smart devices that will modernize and decarbonize the electric and transportation sectors
Pecan Street
What is Pecan Street?

Is it P-cawn or Pee-can?
Its pa-kawn ;)

How does Pecan Street go beyond the simple meters that the utility providers use

Where does the data come from and how do you get access to it?
Dataport

Hardware device challenges
Building codes

Monitoring energy usage also uses energy!

What are you looking forward to the most in the future?
...more
1h 1min
August 25, 2021MEP EP#291: Vaporized Copper Stiction
MEP EP#291: Vaporized Copper Stiction
Bias Test system update
Happy with the two A/D Converters. Got *all* channels running

Made a simple breakout board to be able to access all the pins easier

16 pin IDC cable is holding up to 450V seemingly ok - real test will be with all signals

Resistor measurement was adjusted slightly

Checked against 4 multimeter and getting values “in range”
Next steps
Finish a first version of the arduino code

Merge the skipi communication with my code

Solder into an actual amp to get real world values

Schedule next python thing
Jiva Materials
“The World’s First Fully Recyclable PCB Substrate”

https://www.jivamaterials.com/

PCB board that when soaked in hot water starts to delaminate
Jiva is in the process of ensuring that Soluboard® is compatible with aqueous PCB fabrication processes. Jiva is also engineering Soluboard® to be resistant to high humidity environments.

No technical specifications yet

Circuits/metals are applied in traditional ways (plating and etching)
Relay Dissection
Had a relay stick closed during some “experimenting”

Cut off the top to find out what happened
Fixing circuit boards
Methods

Reddit post/thread that spawned the converstation
...more
56min
August 18, 2021MEP EP#290: Avoiding Bean Counters
MEP EP#290: Avoiding Bean Counters
BGA vs. QFP - PCBA cost comparison
Inspired by Tim Jager on the slack channel

48 pin QFP vs 56 pin BGA

Escaping the package
Layer count

Increase in PCB tolerances

Blind and buried vias required?

Inspection costs
Leaded packages like QFPs can easily be optically inspected

BGAs typically require X-ray

Tooling
BGAs typically require small paste apertures and might require more expensive coatings and stencils

Depending on lead spacing you may not need a stencil at your CM for a QFP

Using the MF platform to predict pricing
Napkin math your PCB assembly cost the “easy” way

Come up with a rough Bill of Materials

Draw up a quick board outline that might be the size you require
Enclosures dictate PCB sizes more often then not

Upload to the platform
Can change the bill of materials on the fly to make pricing considerations at prototype to high volume

Ways to control pricing on your PCB Assembly
...more
1h 1min
August 12, 2021MEP EP#289: Snicker Bar Integrated Components
MEP EP#289: Snicker Bar Integrated Components
Minor correction from last week. IEC 60950-1 was withdrawn in December of 2020, and has been replaced by IEC 62368-1 (Product Safety testing standard for “Information Technology Equipment” and Audio Video Equipment)
Defcon 29
How was it?

Attendance

Favorite thing

Badge
Results?

Reception

Talks
TI soic oddities?
TL072

Large indicator mark

Laser marking has the TI logo but the line goes through the dimple

Very offset marking

Sharp cut body?
Tasty Chips
https://www.tastychips.nl/

SSI2140

Based on the original core of the SSM2040 (Solid State Micro Technology for Music )

Voltage Controlled Multi-Mode Filter
Four variable transconductance cells with i-v buffers

Q-compensation

Temperature compensated

http://www.soundsemiconductor.com/
Interesting reverse engineering tactics?
In regards to customer projects?

How often do you have to reverse engineer products or designs?
...more
52min
August 04, 2021MEP EP#288: We have clearance, Clarence
MEP EP#288: We have clearance, Clarence
PCB design rules for clearances
Stephen's favorite calculator

Clearance and creepage

According to the IEC (international electrotechnical commission) a global standards organization
Clearance - The shortest path between two conductive parts, or between a conductive part and the bounding surface of the equipment, measured through air

Creepage - The shortest path between two conductive parts, or between a conductive part and the bounding surface of the equipment, measured along the surface of the insulation

IEC/UL 60950-1 Safety standards - has more in depth information on spacing and how to handle mains

IPC2221 generic pcb design rules - Has simple information on spacing vs voltage

The creepage requirements depend on
insulation material group
Comparative Tracking Index (CTI) is used to measure the electrical breakdown (tracking) properties of an insulating material. Tracking is an electrical breakdown on the surface of an insulating material wherein an initial exposure to electrical arcing heat carbonizes the material. The carbonized areas are more conductive than the pristine insulator, increasing current flow, resulting in increased heat generation, and eventually the insulation becomes completely conductive.
I 600V

II 400 to 600V

IIIa 175 to 400V

IIIb 100 to 175V

pollution degree
Degree 1 - no pollution

Degree 2 - non-conductive contamination that might temporarily become conductive due to condensation

Degree 3 applies to conductive pollution, or to dry non-conductive one which could become conductive due to condensation

working voltage

Altitude and elevation - Multiply by 1.48

Appliance insulation class
Functional

Basic

Supplementary

Double Insulation - Double the creepage

Reinforced - Double the creepage

IPC2221 requirements - Actually tend to be larger
External

Internal

Coated
Stephen’s thoughts on the AND!XOR hardware puzzle
...more
55min
July 29, 2021MEP EP#287: Biased For Arduino
MEP EP#287: Biased For Arduino
Bias Test System
Got the first board built and installed on an arduino

First tests were a success

Arduino library - works “first” time
Adien Akhmad

2.5V reference voltage
MCP1501T-25E/CHY

0.1% initial accuracy

50ppm drift

I have measured a handful of these at work and have found the output to be within this range - 2.498

Arduinos and USB are noisy

Resistive measurements via constant current
Opamp driven constant current source

1mA output current measured @ 1.001mA with a 1k resistor

Output current is somewhat load dependent - higher at higher resistance values

Possibly should have gone with a parallel opamp config

Validation
Voltages seem to be reading well.

0 to 300V was within 1% of meter

Small “offset” reading
This is due to input buffer amp offset.
Datasheet calls out 125 as typical and 750 as max

I have seen the 100 to 400uV range

Will calibrate out

When doing a simple offset correction I can get 0.00000X readings

For resistive measurements there is a strange gain offset error

Verified the current and voltage but the readings to not match up

About 1.7% low for all readings

What is next
Finish validating the hardware with better standards and meters

Merge the scipi and ads1256 library

Make the gui

Profit
Gripes about arduino
When do you bite the bullet and fix a problem?
Pin header

Mounting holes

Solution….
Custom pin header

Custom plastic “sled”
Supply chain oddities
Surprisingly Linear Tech devices are in stock but not Analog Devices?

Working on that Linear Tech Automotive power supply design

LT8672
...more
59min
July 22, 2021MEP EP#286: FTC “Nixing The Fix” Report
MEP EP#286: FTC “Nixing The Fix” Report
FTC “Nixing The Fix” Report
The debate around repair restrictions illustrates the limitations of MMWA’s anti-tying provision in repair markets. While the anti-tying provision gives consumers the right to make repairs on their own or through an independent repair shop without voiding a product’s warranty, repair restrictions have made it difficult for consumers to exercise this right. Although manufacturers have offered numerous explanations for their repair restrictions, the majority are not supported by the record.
How manufacturers may limit repairs by consumers and repair shops, and how those limitations may increase costs, limit choice, and impact consumers’ rights under the Magnuson-Moss Warranty Act
The statute is remedial and is intended to protect consumers from deceptive warranty practices
Consumer products are not required to have warranties, but if one is given, it must comply with the Magnuson-Moss Act.

Defines definitions and disclosure standards

Bars manufacturers from using access to warranty coverage as a way of obstructing consumers’ ability to have their consumer products maintained or repaired using third-party replacement parts and independent repair shops.

A manufacturer with market power that has refused to provide consumers or aftermarket service providers with key inputs (such as parts, manuals, or diagnostic software and tools) may be subject to antitrust liability for maintaining its monopoly, if the effect of such conduct is to harm competition
What is market power?

Repair Restrictions
Physical
iFixit has a repair index for devices

Should manufacturers disclose how “repairable” the device is?

Reports indicate that consumers would rather have a long lasting device over a “sexy” device.

Restrictions on parts, repair manuals, software, tools

Designs making repair unsafe
manufacturers provided no data to support their argument that injuries are tied to repairs performed by consumers or independent repair shops.

Telematics

Quality of Service of the Repair Process
Dealerships suck in terms of service

Mainly covers safety and “proper repairs"

Right to Repair advocates state that OEMs do this to themselves by not providing proper documentation on repair practices

Application of patent rights / Trademarks

Disparagement of non-OEM parts

Software locks

EULAs

Liability and Reputational Harm
Talking points for right to repair
Timing of Repairs

Price of repairs

Environmental Harm

Small Businesses and Employment

What can the FTC actually do?
Revise its Interpretations of the MMWA to

Make clear that certain repair restrictions could violate the MMWA

Is this like the ATF “reinterpreting the laws”?

Self-regulation

Transparency of Repairability by OEMs/Industry
...more
1h 22min
July 15, 2021MEP EP#285: Let The Robots Do It
MEP EP#285: Let The Robots Do It
Finally real engineering… follow up
What is the most computational intensive work you have had to do on the job?
Mixed Integer Non Linear Optimization problem
Apopt solver

Pyomo

SK -2d polynomial matrix...thing

Email from a listener!
Our “assessment that it is uncommon for engineers to need this is quite biased since both of you work in manufacturing”

Clarification of point

Most of Stephen's time has been split manufacturing and design

Theory classes do reinforce your “gut check” and “rules of thumbs”

Python SCPI Test Development
Recap of Saturday

Stephen’s Bias Test Board

Issue with devices resetting/losing communication

Bias test board
Finding the right A/D kind of sucks
It is never just resolution

Lots of variables to juggle
Resolution

Speed

Cost

Accuracy

Package

Features

Not so features

PGA

Digital filtering

Caddock 1776-C681 resistive divider
0.05% tolerance

Convenient 1/n division

0 to 1000V down to 0 to 1V

Settled on ADS1256IDBTG4
All the bells and whistles

Opamp constant current driver to push 1mA
Resistance range = 100R to 2.2k so 100mV to 2.2V

Joe biden and right to repair
July 9 executive order includes wording for right to repair
To address persistent and recurrent practices that inhibit competition, the Chair of the FTC, in the Chair’s discretion, is also encouraged to consider working with the rest of the Commission to exercise the FTC’s statutory rulemaking authority, as appropriate and consistent with applicable law, in areas such as

Unfair anticompetitive restrictions on third-party repair or self-repair of items, such as the restrictions imposed by powerful manufacturers that prevent farmers from repairing their own equipment

Federal trade commission released “Nixing the Fix” May 2021
...more
1h

FAQs about Circuit Break - A MacroFab Podcast:

How many episodes does Circuit Break - A MacroFab Podcast have?

The podcast currently has 448 episodes available.

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