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Circuit Break - A MacroFab Podcast
Circuit Break - A MacroFab Podcast episodes
- MEP 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
47 min - MEP 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)
1 hr 23 min - MEP 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?
1 hr 1 min - MEP 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
56 min - MEP 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
1 hr 1 min - MEP 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?
52 min - MEP 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
55 min - MEP 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
59 min - MEP 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
1 hr 22 min - MEP 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
1 hr
About Circuit Break - A MacroFab Podcast
From the publisher's feed
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.
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