Circuit Break - A MacroFab Podcast

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 Syys 20211h

MEP EP#291: Vaporized Copper StictionBias 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

25 Elo 202155min

MEP EP#290: Avoiding Bean CountersBGA 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

18 Elo 20211h

MEP EP#289: Snicker Bar Integrated ComponentsMinor 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?

12 Elo 202151min

MEP EP#288: We have clearance, ClarencePCB 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

4 Elo 202154min

MEP EP#287: Biased For ArduinoBias 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

29 Heinä 202158min

MEP EP#286: FTC “Nixing The Fix” ReportFTC “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

22 Heinä 20211h 21min

MEP EP#285: Let The Robots Do ItFinally 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

15 Heinä 202159min