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....
Sep 15, 2021•47 min•Ep. 294
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...
Sep 09, 2021•1 hr 23 min•Ep. 293
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 ut...
Sep 01, 2021•1 hr 1 min•Ep. 292
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 act...
Aug 25, 2021•56 min•Ep. 291
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 ...
Aug 18, 2021•1 hr•Ep. 290
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...
Aug 12, 2021•51 min•Ep. 289
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 equip...
Aug 04, 2021•54 min•Ep. 288
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 ...
Jul 29, 2021•59 min•Ep. 287
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 repai...
Jul 22, 2021•1 hr 21 min•Ep. 286
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...
Jul 15, 2021•59 min•Ep. 285
MEP EP#284: Real Engineering for a Real Engineer When to Schedule Python for Engineers Intro Stream? This Saturday July 10 at 6PM central Twitch URL for the stream Overview of the Topics Setting up a python environment on Windows PC Python script talking to an embedded device over serial communication Not a how to write python/code stream Might get into Tkinter for GUI stuff Embedded Device will be Arduino SCPI to handle the coms List of items Arduino Windows PC PyCharm PinoTaur Production Updat...
Jul 07, 2021•51 min•Ep. 284
MEP EP#283: You Adapt. You Overcome. You Put in a Pull Request. Custom DIY Multimeter? Fun article about meter design Specs DC Voltage Range 1000V Accuracy Resolution Autorange? AC Voltage True RMS? DC/AC Current? Range 10A Resistance measurement 4 wire kelvin Communication USB 2x 16 Character Display for Status Powering the meter Isolated DC-DC converter Enclosure 19” rack 1U Isolated mounting holes Safety HY3131 Digilent has an arduino shield based on this Chip When to schedule python for engi...
Jun 30, 2021•1 hr 3 min•Ep. 283
MEP EP#282: When Print(); Just Works SMT Connector Considerations Switching from Though Hole connectors to Surface Mount connectors Price difference How many insertions? Via Stitching pads Plastic actuator update 420,000 presses and going strong 300 PPM Damn arduino Serial.println() Do Not Use Print For Debugging In Python Anymore Automatic verbose print statements for python! Easy disable Bipolar load switch with multiple enables Would rather not do this in discrete but probably going to have t...
Jun 23, 2021•1 hr•Ep. 282
MEP EP#281: Through Hole Manufacturing Through Hole Manufacturing Processes Hand Soldering Soldering “robot” Wave soldering Design Criteria Pallets Selective soldering Design Criteria Keepouts Lead Forming Pre purchase? Forming with a die? Using hand tools? PCB design Holes Non circular? Annular rings IPC stuff IPC-2221 Generic Standard on Printed Board Design IPC-2222 Sectional Design Standard for Rigid Organic Printed Boards IPC-2223 Sectional Design Standard for Flexible/Rigid-Flexible Printe...
Jun 17, 2021•59 min•Ep. 281
MEP EP#280: Don't Worry About It Adventures in plastic injection molding Beating the bubble Finding a new method of shooting the material to adjust for issues Change ejector pin depth Change material Light bleed Texturing Right to Repair is going global NPR business National Farmers Union Nebraska Legislature Bill 543 Getting a pro right to repair guest on the podcast? Louis Rossmann update Uncle's Brewery Update Setup the boxes Boiled water and got all the hoses cut Next Steps Mock brew day wit...
Jun 09, 2021•1 hr 3 min•Ep. 280
MEP EP#279: Avoiding The HR Pit of Doom, Resume and Interview Tricks for Engineers Engineering Resumes The main goal: To start a conversation The resume is intended to give a snapshot of you not to be your autobiography The person doing the interview probably has other tasks that they have to accomplish Your interview is important but it is likely not their main focus, keep this in mind Too much information is a bad thing - remember people hiring have to read lots of resumes The 1 page rule The ...
Jun 02, 2021•1 hr 21 min•Ep. 279
MEP EP#278: Design With Manufacturing - Altium and MacroFab Ted Pawela Altium's Chief Ecosystem Officer Head of Nexar , Altium's cloud business unit Holds a M.S. in Engineering Mechanics from Michigan State University, a B.S in. Oceanographic Technology from Florida Institute of Technology and an M.B.A. from IE Business School, Madrid, Spain Chris Church Is a founder and the Chief Product Officer at MacroFab Has been working in the software industry for over twenty years, with a focus on robotic...
May 26, 2021•1 hr 18 min•Ep. 278
MEP EP#277: Bunch of Nibbles Tasty Chips segment Harwin EZ-Cable Clips Mac-Eight CZ series Update - E-Z Hook Insulation Piercing Wire Clamp - 8507 Built a housing to isolate the wire clamps COM port snooper / sniffer? Ended up using ' Free Serial Analyzer ' Automating Testing Clock Drift Using an oscilloscope? SCPI or some other method? 115 pages of commands What is inside a scope probe? 10X? Rotary switch pcb - interesting bug? Pcb is 99% done - currently reviewing MF platform experience https:...
May 19, 2021•57 min•Ep. 277
MEP EP#276: Skippy Documentation Fake LM338 Voltage Regulators? X-RAY results Should we Xray legit LM137 and see if the XRAY matches? SCPI or Standard Commands for Programmable Instruments IEEE 488.2-1987 Send command strings over serial to configure and get results from test equipment Test equipment mostly adhere to this with some weird gotchas COM port snooper / sniffer? Is there good software out there that can sniff the buffers / communication string between Windows and a hardware device? Is...
May 12, 2021•1 hr 6 min•Ep. 276
MEP EP#275: Log Stepping Revision Control Log stepper Exercise in madness 24 position stepped attenuator 1db steps with step 0 being -infinite and step 24 being 0db attenuation Requires lots of non standard resistor values Constant total resistance Excel sheet Make before break operation Revision workflow How do you document and handle revisions for schematics and pcbs? Process Get new rev Go to testing Find issues and document Make new revision Repeat Venturing into hobby level SLA printing Ele...
May 05, 2021•57 min•Ep. 275
MEP EP#274: The Pinch Load Thermal Management Part two! Interesting thermal management designs and devices Copper “fingers” Thermal Jumpers Common DRC Problems Annular ring Copper to Board Edge Tolerances of the checks? Why? -0.1mil or -0.00254mm Record Player Deconstruction Tube Amp Schematic Possible Fake components? From the thermal discussion from last week's podcast LM338 or LM317... Opamp Stability Interesting issue with opamps and comparators with latest design Make sure to add extra comp...
Apr 28, 2021•55 min•Ep. 274
MEP EP#273: Beating the Heat Delta Pag Fan Controller Hack Override inverter mod was a success! PinoTaur is in PRODUCTION Gotta start putting together the website to host the documentation Pinotaur.com Supply chain issues! RGB Lighting connector Beating the Heat Talking about thermal management...
Apr 21, 2021•1 hr 6 min•Ep. 273
MEP EP#272: The Digital Mattress Right To Repair Ease of opening for repairs This sounds great but I have some thoughts Reason why phones are hard to open now Security screws only keep out people that probably shouldn’t be opening the device anyways Ultrasonic welding and potting? Access to manuals What if repair manuals don't exist for a product? Small and medium volume products don’t have the revenue or volume to make this kind of documentation Schematics, Circuit Diagrams, and Firmware Access...
Apr 14, 2021•1 hr 21 min•Ep. 272
MEP EP#271: The Right to Repair Right To Repair Dot Org The Right to Repair Electronics refers to government legislation that is intended to allow consumers the ability to repair and modify their own consumer electronic devices , where otherwise the manufacturer of such devices requires the consumer to use only their offered services. This already exists for Autos for the most part Motor Vehicle Owners' Right to Repair Act Ending the "unfair monopoly" of car manufacturers maintaining control ove...
Apr 07, 2021•1 hr 11 min•Ep. 271
MEP EP#270: Radio Frequency Eyeballs Cool XLR connector with a smart method of assembly NC3MD-H-BAG NC3FD-H-B XLR with two parts - one for mounting to the enclosure and the actual connector. Assemble separately - allows you to test the electronics on the board Insert and turn a small screw and lock the connector to the body Keysight scopes are now “dark mode” Jeff Keyzer comment on Twitter It is like the evolution of PC cases for test equipment Chipmakers are hustling to make auto chips--and say...
Apr 01, 2021•37 min•Ep. 270
MEP EP#269: Illuminati Moment Fan controller for Jeep MCU P/N: G80F960AP 8051 core Chinese Generic MCU Override signal passes through a diode then pulled up with a 10K to 5.0V Diode to prevent back feeding voltage if you slap 12V onto it Mosfet inverter as the fix! PinoTaur REV 4 has Arrived! Goes into final testing for production certification! RGB LED boards testing Mind the details - Cross talk Actually ran into this as a unique problem Those values in datasheets can creep up Beat head on tab...
Mar 24, 2021•56 min•Ep. 269
MEP EP#268: Avoid The Extremes Fan controller for Jeep Brushless fan temperature controller Nothing fancy but the “override” signal is ground triggered! Will have to invert the A/C compressor signal with a relay Controlling PCB cost What are the knobs that can be turned to adjust the cost of the PCB itself? The easy ones Size (not necessarily rectangle) Panelization Base material TG ratings - The glass transition temperature FR4 Trace/Space Minimum hole size Mask Color Surface finish Copper weig...
Mar 17, 2021•1 hr 4 min•Ep. 268
MEP EP#267: Honey, I Shrunk The Parts Tradeoffs on component sizes "World's Smallest" Claims Can Come With Trade-Offs Design and Production considerations when going small Different PCB Design Rule Checks PCB pricing Via in Pad Escaping Components Silkscreen Part placements Assembly documents Tooling Paste Jetter Stencil coatings STICKERS/Labels for products Find out what label printers your CM is using Consumable items Label Material Location! Location! Location! Printing Instructions and Infor...
Mar 10, 2021•55 min•Ep. 267
MEP EP#266: The Expert Design for Manufacturing – Beyond the Digital Domain Webinar that Chris Church (Co-Founder of MacroFab) will be co-hosting with Edwin Robledo of AutoDesk. Building a Program and Testing procedure for your first production run Take lots of pictures Keep it up to date and version controlled Hand off the procedure to a colleague and have them run through it Work with your CM MacroFab works closely to help flesh out procedures and fixture designs What is you acceptable fall ou...
Mar 03, 2021•55 min•Ep. 266
MEP EP#265: NuFuel and Gas Classic Resealing 12oz cans? FAIL! Worked till can shaken a bunch Improvements Working on finding a softer sealing surface Currently using a Shore 55A neoprene rubber sheet Increase seal pressure on can Carmakers wake up to new pecking order as chip crunch intensifies Follow up from last week's discussion on Auto industry shutting down production due to lack of electrical components. Both automakers and chip manufactures are pointing fingers Chip makers point at the au...
Feb 24, 2021•1 hr 12 min•Ep. 265
