The Amp Hour

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Sowing Discord Apr 13, 2020

Show notes

Today’s show is sponsored by Rohde & Schwarz. We hear in the ad today from James Lewis (@baldengineer) about how to use an oscilloscope and how probe capacitance can affect measurements. For more information about the scope discussed today, check out AskAnEngineer.us.

Seth Hillbrand did a KiCad stream working on Medtronic's ventilator files.
Will be interesting to see how the license for the released files changes once the pandemic is over.
FormLabs SLA printer
Spreadsheet of every project
Dave did a repair video after an inductor blew in a found laptop
Kits for parts, parts drawers
Alvaro (past guest, remote correspondent and co-host of the Unnamed Reverse Engineering Podcast) uses PartsBox.io and a barcode scanner to set up a home inventory system for electronic components.
Dave considered buying the inventory of an electronics hobbyist.
IPC standard pad sizes
Density heat map
Members of The Amp Hour Patreon now get access to an exclusive Discord server. We're looking for other ways we can give back to our Patrons.
3H meetups are going virtual as well. Have you always wanted to join a 3H? There is one a Chicago meetup coming up on Tuesday April 14th. Join the 3H discord if you'd like to connect any time.
The Myth of the 3 Capacitor Values
Eric Bogatin on the show
Application notes for FPGAs
Eric's Rules of Thumb articles
We were asking some questions posed from our Patrons on Discord
Microcap is free now
Mike Engelhardt on the show
After listening to our episode with John Day, an apps engineer was asking if there were other practical app notes that don't exist and should be made.
TI AN-1148
Keithley Low level measurement handbook
Microchip app note about LCDs

Thanks to peakpx for the sowing picture

An Interview with Kerry Scharfglass Apr 06, 2020

Show notes

Welcome, Kerry Scharfglass (@borgel)!

This episode is sponsored by Screaming Circuits, who are operating throughout the COVID-19 shutdown to serve medical customers (and normal customers too!). If you need priority service for a medical device related to Coronavirus, please let them know upon checkout. All other orders will be on a non-standard timeline guarantee (because of staffing, priority orders), but will have the same high quality assembly that Screaming Circuits is known for.

Kerry was using Upverter for layout and switched to KiCad.
He was designing a badge for DEF CON, which he did multiple years.
The Dragonfly Badge was based upon Neal Stephenson's Diamond Age
Synchronizing clock over IR helped each piece of hardware coordinate patterns.
Kerry has done two HDDG talks:
- From 1 to 100: Scaling and Selling a Personal Electronics Project'
- Design for Manufacturing
- There was another talk by Whitney Merrill about Badgelife that helped Chris understand people were building real hardware.
Kerry Supercon talk about "medium scale"
SnapEDA
Talk with Nadya, Ben, and Zach
Things learned from 'small scale hardware war games'
Photos of units, colorful diagrams
"All the different things you use profit for"
Moving from 4 layer to 6 layer
Kerry's first job out of school was at Lab126, the company that makes hardware for Amazon.
At the time, they had released the Kindle and KindleFire.
He was working on a prototype for what became the Echo.
A (wearable) ring for Echo
Wallwart that is cheap enough to throw into everything
OMAP3 with DSP core
Tracking COVID cases using phones
Wake word on device
Initial integration with Hue worked over UPnP
Built with Yocto
After Lab126, Kerry started working at Mindtribe. They were recently acquired by Accenture.
Dockless scooter
Speed to market as a design constraint
How did it impact the firmware side of things?
"If you can't communicate with the client about what you're doing, it doesn't matter what you're building at all"
Whiteboarding as a skill in front of clients
Mercilessly hack away at requirements
Chris has dealt in the past with consultants who are rude (and doesn't want to be like that).
Kerry is now the Lead firmware engineer at Span.io. They are making power panels that can work better with solar and battery systems.
Things that are different as a full time engineer vs a consultant: "I have all of the skin in the game instead of some of the skin"
Moving into management vs moving to smaller company
Storage + Solar
The Powerwall doesn't show up as a full system, it needs to be integrated by an electrician or similar.
Industry is different than commercial
"Designing for service"
One customer is the home owner, one is the installer
EEVblog videos about solar
Changing wifi connection by the installer
Altium to KiCad converter
Hackaday articles
- Inner workings of a PCB
- Embedded file systems (LittleFS)
Check out more about Span.io

Medical Kits, They're The Future Mar 30, 2020

Show notes

Chris stupidly did a workout while working from home during the COVID-19 shutdown
Chris has a new "lab" at home as well
O'Reilly shut down events business
Chris went to the Solid Conference in the past, run by Jon Bruner (who used to work at Formlabs but has moved on)
Conferences going virtual
Open Source Ventilator discussion on Hackaday
Regulation for medical
Dave getting stimulus from the Aussie gov't
Chris is getting a custom cable made
Custom LED sign
Product update
Solus glass
Chris finally went LeadFree with GC10
Greg Davill discussed this paste when he was on the show
Heat profiles were tough to find
Dave warned against mixing of thermal mass components
Vapor phase oven
Forgot boards in the oven
Dave made a video about LLC resonant converters, but it was a different topology (showing how many there are out there)
Cuk (chook?) power supply
Walt Jung
Contactless fluid measurement app note from ADI
Akiba on the show talking about ultrasonic montioring of water levels
Learning in Lockdown days
Dave is working on testing Akaline leakage (again!)
Fluid leaking happens from a low load
Batteries can develop a reverse charge!
VAT (and associated processing fees) on small packages coming into the EU will be changing

Thanks to crises_crs for the lego xray photo

An Interview with John Day Mar 22, 2020

Show notes

Welcome, John Day, Technical Fellow and FAE from Microchip!

John has worked at Microchip for 27 years! It was almost startup when he joined in 1993.
He previously had worked on IO subsystem modules at DEC and had interacted with FAEs.
He did some research on the company before joining, by checking out their databook
John's first computers were the C64 and the TRS80.
Microchip was a spin-off of General Instruments in 1989, with Steve Sanghi as the head of the company (still in charge!)
Focus was on low cost components, like ROM
We take In Circuit Emulators (ICE) and In Circuit Programmers (ICP) for granted these days, in the 80s and 90s you could only really use emulators.
With the lower costs, engineers could go to production on an EPROM. This made more devices "field programmable".
Why was the PIC was different when it came out?
- There really weren't C compilers
- Most programmers are not familiar with the ISA
- Used to be writing direct assembly code
- Didn't have a lot of peripherals
- Wouldn't have a peripheral for i2c/smbus or similar
- Timing would be really critical
- PIC was single cycle
The first part was the PIC16c64, it had no interrupts, 512 words.
Microchip was early movement into flash, the first component with it was the PIC16f877 in 1997
They were also the first to have in circuit debugging; John Andrews and John Day chatted about having this and did a proposal for the debug registers to the chip designers. The software group followed. This was for MPLAB 8.
ICD1 was developed outside of Microchip, but later pulled in house
It came up after talking to customers about their needs
The PIC32MZ was another good example of working with customers. They talked with Clint Cole and Keith Vogel of Digilent. They ran into an ADC non linearity that drove changes to the silicon.
PIC32EF
In order to issue and errata, engineers need to cut down source code to minimal size for isolation of the issue.
John gets to work with automotive, gaming, commercial, and a lot more types of customers.
Sometimes he finds himself writing code for customers, like special IP that is needed. This happened for a high volume part that needed better test coverage to find errors that happened once every million units. It turned out to be a brownout problem.
John used and likes his Saleae logic.
Microchip started an analog products group in late 90s, especially because a lot of the IP was developed for the microcontrollers.
They bought Microsemi / Actel 2 years ago.
FAEs at Microchip now have "specialist areas"
ATC chips are ultra secure chips that hold root keys
App Notes
- The LED Cube is a Harmony reference design, meant for PIC32, Harmony3
- In-Circuit Serial Programming (ICSP™) of Calibration Parameters
- D/A Conversion Using PWM and R-2R Ladders to Generate Sine and DTMF Waveforms
  - DTMF for Plain Old Telephone Service (POTS)
  - The R2R ladder is also used on OpenScope
- Piecewise Linear Interpolation on PIC12/14/16 Series Microcontrollers
  - Linearizing a sensor with low power components
App notes can take a while: the LED cube took over a year. This is because they're publishing them, in addition to their regular job.
People expect code generator / configurator tools these days, so the nature of app notes have changed.
John assigns himself personal projects to learn new technologies
Building Nixie tube clock to learn boost converters, ethernet stacks (this is shown in the photo above)
Aside from microcontrollers, John is a huge fan of Pinball
"You can always have space for a pinball machine". In fact, he fit a pinball machine in his college dorm room.
Gottleib Genie
Ran on Rockwell 4 bit micros - 3 of them
Batteries used to retain settings, but they would leak and destroy MPU
Ralph Fien in Germany took MAME project and made a pinball machine, which all ran on a RPi
3 PIC18s to talk to IO
There are drivers on separate boards, similar to TIP102s.
4 bit latches on the bus
Periphieral IO Expander (PIA)
NI-WUMPH
Mission Pinball Framework (MPF) allows you to write all your game rules in Python.
Ben Heck made a custom pinball machine
John's first machine was a 1973 Gottleib Kingpin, for which he did a restoration.
You can hear John on The Classic Pinball podcast for episodes 27 and 28.
John has had some interesting experiences as an FAE:
- He was offered a gig (in cash) to build a cable tv descrambler
- UPS design for a customer in a bad neighborhood
- Almost blowing himself up while building high voltage power supply during co-op
John is a fan of Dave's teardowns and learning from them

Man Behind The Curtain Mar 16, 2020

Show notes

This episode is sponsored by Screaming Circuits. As discussed in the ad this week, Duane Benson has written about the importance of good footprints and avoiding via-in-pad on the Screaming Circuits blog.

Coronavirus has a lot of people working from home. Dave says Chris should have finalized the "portalab" project talked about many years ago.
Chris travels with his Analog Discovery 2 (which can be bundled with Contextual Electronics), the Aneng 8008 (recommended by Dave), and an assortment of dev boards.
Schools are telling students not to come back to Uni for Coronavirus.
Dave needs to refresh his $50 DMM shootout for people working at home.
Clint Cole from Digilent was on the show talking education
Chris finally got a 121GW and likes it! But he needs to update the firmware.
Hot air + soldering iron is a good buy if you're going to be at home. If you're moving around a lot, perhaps a TS100 or TS80.
Dave was tempted to buy an Electric Ute (pickup truck). It was a DIY project built with love (video)
Chevy Volt discontinued in the US, but the Chevy Bolt is an interesting replacement with a long range. It may end up in Australia, but many of the EVs are expensive there.
Dave doesn't plan on building a DIY powerwall (battery storage for excess solar capacity) but Paul Kennett and Jehu Garcia (couldn't remember his name) both have multiple videos about this topic.
150K limits on business deductions in Australia
Dave's workspace is up for lease! Work near Dave...with him as your landlord!
Boosted Boards laying off people, because of tariffs. Phil from adafruit wrote about this and also how adafruit has been dealing with the tariffs and the COVID-19 shutdowns in China.
Discussion on the forum
10 day hospital build in China
Seeed Studio started the OPL a few years back. They since have introduced the "Shenzhen OPL", which isn't a method of making parts more genericized, but instead lists a lot of parts that might not be available outside of the China supply chain.
Dave thinks businesses will be so hard up for revenue, that the next EEVblog meetup will be at the Sydney Operahouse
The Open Hardware Summit was all virtual. You can watch the videos on their playlist of the event.
The CERN OHL v2 is now out. Watch Javier Serrano from CERN discuss it during his Open Hardware Summit talk.
Unsurprising headline: "Reclusive Engineer Stays In Lab"
Chris played "the man behind the curtain" when a last minute board incident meant that he needed to simulate parts of a system using an Analog Discovery 2 with some scripting.
A fun page of Bit Twiddling (bitwise operations) for writing tight C code.
Dave is a recursion fanboy, he used it in his formula solver program back in the day.
Check out this visualization of Moore's Law and how processors have tracked it pretty well.

An Interview with Adrian Tang Mar 09, 2020

Show notes

This episode is sponsored by Rohde & Schwarz. Check out their reviews of their new product line at AskAnEngineer.us, including a video review from friend of the show Shahriar from The Signal Path.

Welcome, Dr Adrian Tang of NASA’s Jet Propulsion Laboratory (JPL)!

Adrian is the only CMOS chip designer at JPL (though he has grad students)
He got his PhD at UCLA working on ultra high frequency devices. Check out some of his projects on his personal website.
JPL has instruments that can measure these high frequencies.
Terahertz spectroscopy
There's a noise floor in the universe, but gases tend to emit at certain frequencies in the 50-500 GHz region.
Resonance in the THz range
Pressure has to be low
Trying to process as much bandwidth as possible
Try to get 3GHz of bandwidth out of devices.
4000-8000 point FFT
Power budget might only be 50W on a satellite.
Was doing commercial CMOS previously
Horn antenna + lens
Tempest D mission
Using cosmic background as a cal point
What is the output data?
Time domain data
Using the LO to remove the movement of the spacecraft
Doppler properties
Herschel telescope
Reflector to focus it down into the feed is about a meter
Has to be accurate to lambda over 20
Goes into a receiver feed
Mixer needs an LO
IF comes out of the mixer at 3-4 GHz
Takes it through the IF chain
Amps and filters
Apply a window function
Polyphase filter
Compute the FFT
1 sample isn't enough to see something
Average over 1000s of samples
Rosetta orbiter was put out by ESA
The more spectrum, the more chance to discover something
RekTangLE balloon mission
Measuring NO2 at 570 GHz
Did have a failure
This was one of the first CMOS chip to do atmospheric measurement
Isotopes have different lines
Heavy water and regular water
Heavy water is naturally occurring
Everywhere you go, the ratio is comparable, in the solar system
Moreau on a jovian comet
How have things moving into CMOS?
Active and Passive Receivers
Northrop Grumman makes some of the only amplifiers that can operate up to 600 GHz
Past guest Tony Long talked about (relatively) high frequencies and works at NG
Passive is a mixer first instead of an amplifier first
Schottky mixer
Express sensitivity in terms of difference
Hot electron bolemetric mixers
Exotic semiconductor junctions
What has improved?
Windfreak
Packaging is not simple
Waveguide is the only thing that will work at 100G
They do a lot of the fab in house at JPL
Measuring snow in the Sierras using Ku band radar
SWE - Snow water equivalent
SpectreRF
Built in self test
Everything on chip is the best case
Using different process technologies
65 nm process technology cannot work with 180 GHz signals.
What is this stuff useful for?
Short range 60 Ghz
Ken Cooper
Threat detection, 680 GHz radar, 30 GHz bandwidth
Another balloon "whatsup" will go up soon. Read about it and other balloon launches (past and present) here.
Astros - 8 px, multi THz telescope
Ground penetrating radar
UAV snow sensor
Check out more of Adrian's work on sadcircuitdesigner.com
Or check out his papers on his "articles" page

Shine A Light Mar 02, 2020

Show notes

Today’s episode is sponsored by Screaming Circuits, who can place the newest and smallest pitch parts, even on low run, quick turn assembled boards (their specialty)

Dave will be taking his new BlackDiamond spot 325 headlamp when he goes canyoning
Lithium battery can be 4.8V out of the pack
Forum on mfg
Chris Church was on the Macrofab Engineering Podcast talking about the Coronavirus effects on manufacturing
Bill Gates in documentary about viruses
Zoom stock really taking off due to coronavirus
DO NOT USE THIS CHIP
NAS in the Trash (eevblog video)
Intel C2000 atom processor bricks devices
LPC clock 0
Errata on C2000
Episode next week will be with a designer who does 300 GHz + designs (?!)
Chip of the Week: The Tibbo Plus1. It's an all-in-one SOC that runs Yocto Linux.
Chris has been challenged with board clearances and is hoping KiCad v6 DRC improves some features.
Morse Blinkies as a Service: a web program by Ian Ross that generates circuits on demand...to make morse codes.
It uses SKiDL, which is a text based netlist plugin for KiCad written by former guest Dave Vandenbout. Dave gave a keynote about SKiDL at KiCon 2019
EEVblog JTAG video / Boundary Scan
Tag Connect
Making a toaster from scratch
How we record the amp hour

Thanks to Simon Scarfe for the picture of the headlamp scariness

An Interview with Paul Thompson Feb 24, 2020

Show notes

This week we are sponsored by Keysight. Amp Hour listeners get a bonus entry if they sign up for the upcoming Keysight Wave event using this link, which starts on March 2nd. You can also view some of the content discussed in the ad this week, such as the The ESD Checklist, 4 easy ways to blow up your test gear, and Can a cable electrically damage equipment? Welcome, Paul Thompson, CEO of Pakton Technology

Pakton make electric fence controllers
Dave found a Pakton controller in the dumpster
Paul thinks it was sent out for EMC testing and never came back
Transformer
SCR
MOV
Follow @JVAtechnologies on Twitter (the brand behind Pakton)

An Interview with Ben Krasnow, 8 years on Feb 17, 2020

Show notes

Today’s episode is sponsored by Screaming Circuits. Listen to the episode to hear about the monster through-hole pick and place machine they have on premises for their legacy customers. Check out this link to get an instant quote on your next board assembly.

Welcome back, Ben Krasnow!

We first talked to Ben 8 years ago.
YouTube has changed quite a bit since then, as has Ben's channel:
- It's now called "Applied Science" instead of the original bkraz333 (though that link is still the official one)
- It now has 600k viewers and many Patreon sponsors
When Chris asked about replicating the paper setup (like from a research paper), Ben says it's a recipe. It's easier to follow and get started.
An artist had exclusive license to use
Vantablack, which made Ben wonder if he could make some. (spoiler: he can)
Applied Science gets lots of great feedback from technical viewers, including some who have insider knowledge.
Since the last episode Ben was on he worked at
- Valve Software, with past guests
After Valve, Ben went to go work for GoogleX in 2014. They wouldn't tell him what he was working on!
At 6 years, this is his longest running gig.
Joined science team with 20 people, which has grown into Verily Life Sciences. He's able to talk about (some) things now.
Ben has been on Embedded.fm twice in the meantime:
- 119
- 184
Verily announced an accommodating contact lens, which helps with presbyopia
Though Ben didn't work on that project, he had previously made am LED contact lens
Verily have a micro-fab on site for making and prototyping such small devices.
Ben's lab is a bit more simple, he says it almost looks like his home lab.
Chris compared the research portions to Bell Labs
When the team hits a wall, they focus on finding and integrating new tech.
Chris asks if the development is a push or a pull. As in, does the customer request certain technology or do they "deliver" it to the market and test whether it will work?
Verily is working with a US centric view, especially given the high costs of the US medical system.
Being an inventor type person in healthcare includes figuring out what the market looks like
How much iteration?
Verily have made hundreds of certain devices to test whether they can be manufactured "at scale" and that they will work in large numbers.
Primarily they partner with other (medical) hardware makers and Verily licenses the tech to the OEM.
A common demo in the Verily lab is a little motor that uses combustion because battery technology isn't power dense enough for what they need
Ben often gets comments about safety on the YouTube channel
He likes to be application driven
Wikipedia op amps
Ben is a KiCad user, he likes the push and shove feature.
One of his most popular video shows vinyl and LP under a SEM. The tough part is pulling out the bitstream, which he currently does with a Teensy.
Rubber band fridge
Drill through EDM
Ben tried over 80 different methods to get PCB traces on a piece of plastic. This is a good example of the importance of starting from a paper or a patent.
Chris thinks that Ben is a great example of the behavior defined in Grit
Tim Ferriss talking about fame/money
Cookies DOE
Exceptionally hard and soft
Ben kept blowing up the controllers for the Apollo Electroluminescent display. Ben later gave a great talk about the experience at Supercon
Needed a source of radioactive material, which are apparently easily acquired in static brushes for LPs.
Want to hang out with Ben in person? He's usually at the Hackaday Supercon
Follow Ben on Twitter and be sure to subscribe to the Applied Science YouTube channel
Books mentioned in this episode:
- Elon Musk Biography
- Skunkworks

Why isn't this working? Feb 14, 2020

Show notes

A special mid-week extra episode! Plus it’s a crossover show with Embedded.fm! We discuss how both Chris Gammell and Chris White are working on projects to learn more about firmware.

They were kind enough to take notes, so go over to their site to check out the links attached to this episode. And if you haven’t already subscribed to Embedded…what are you waiting for?