The Amp Hour

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Natural Sciences
**The Amp Hour**

The Amp Hour is a weekly conversation about electronics and the people who design them.

Latest Episodes:

Fan Fanboys Sep 11, 2023

Show notes

Chris is out of stock on Tindie and will no longer be a seller (though he was barely one to start with). Props to all the sellers out there!
Media mail is a low cost post option in the US
Colin Mitchell allowed people to pay with stamps instead of money orders back in the day
There is always a struggle for hardware engineers to price a product at the value in the marketplace and not just the cost of parts
Teardown of DHO800
Heatsink testing (live during the show)
CFD
Controlled depth routing
We discussed Joe Grand's thin boombox last time, Dave watched a talk where he explained more of the process
Scotty from Strange Parts did an awesome tour of the JLC PCB Flex factory
Skewed expectations
Dave was wondering why during the production assembly of scope that they populated caps but not silicon
Intel is investing in ARM, RISC V (say what now?)
eBay U1273A meter
Old stock
30 year old tek chips

Moving Down The Stack with Scott Williams Sep 05, 2023

Show notes

Welcome back, Scott Williams of Xentronics!

Scott was on Episode 624 talking to Dave about the business of consulting, but they discussed Scott coming back on to get more into the technical side of things.
Chris listened to the episode and wondered if Scott would get more pulled into management of the day-to-day
There's a new program in Victoria (Australia) to enforce deposit/rebates on bottles and cans. This opened up an opportunity for an electronics project.
Bin management is another common IoT project
Industrial - Site Hive is a long-time customer in the construction space
Consumer goods
Scott said he's likely to reach for a Raspberry Pi CM4 for quick prototyping/POC
Wht about the high density Hirose connectors?
Does Xentronics "go down the stack" by using tools like Buildroot / Yocto?
Cameras make products much more difficult. Raspberry Pi cameras have a CSI interface but aren't "standard" per se.
When starting projects, Xentronics is likely to pull out ESP32 for WiFi, Nordic for Bluetooth, STM32 for generic processing
Bare metal vs RTOS? Normally they start in the RTOS space to add things later
Pre-made / prior art
Colin Karpfinger of Punch Through, a firm that largely focuses on Bluetooth
EMC resources/courses
- PCEA educational EMC
- Todd Hubing
- Keith Armstrong
- Ken Wyatt
- Wurth seminar - Scott never got the recording, but will try again and we'll update here/reddit if he gets it!

Garbage Ninjas Aug 28, 2023

Show notes

Chris joined the 2010s and got a step tracker, the Fitbit Inspire 3
There are commercially available teardown reports you can buy
One of the sensors on board is well supported in Zephyr. This influences how Chris chooses parts.
The RT500 (discussed by Aeden in episode 638) is supported in Zephyr and targets the smart watch industry
Kalman filters are pretty amazing
Dave blew out his other knee (!) and went to go see a Podiatry specialist to get his gait analyzed. He has "impressively flexible feet"
Dave did a teardown of the classic Boombox from Say Anything
Joe Grand made "The World's Flattest Boombox" to showcase a piezo speaker. It was a really cool PCB!
Joe Grand was also on The Amp Hour (twice!)
- Episode 60, one of our earliest guests
- Episode 575 in early 2022 when Joe was hacking on Trezor wallets
eBay
Garbage ninjas
Recycling electronics
uSupply video
Part number stuff
Chris has been putting a design through Macrofab. Chris and Parker were on episode 243.
Tempo automation has maybe (probably?) shut down. There was a weird email that Chris shared. After the show, Chris found a post about how they're down to 7 employees, so probably aren't manufacturing any boards...
Making a RISC V processor in 100 lines of Verilog!

Calibration & Repair with Ian Johnston Aug 22, 2023

Show notes

Dave and Ian Scott Johnston discuss the PDVS2mini DC Voltage Calibrator Source, production, China, CERN, ebay reselling, test gear, pick and place machines, assembly, automated test systems, and Youtube repair videos.

https://www.youtube.com/@UCtiK8QrcCrsjDXpKzB1PO1A https://www.ianjohnston.com/

Sad Violins for Superconductors Aug 13, 2023

Show notes

Chris is developing a booming "dad" voice, perhaps?
Memorizing modem sounds
The Amp Hour turned 13 years old (episode 1 went out Aug 12th, 2010)
The Fluke 87 is 35 years old
Everyday DMMs
Chris enjoyed Dave and Toby discussing the DMM a lineman uses
Bryman
Dave will be giving a talk at a University sooon...should he dress up like Bob Pease, the Czar of Bandgaps?
Dave made a video about one of the LK99 groups
What are the practical limits of superconductors?
Meissner effect is how superconductors levitate
Maglev trains
Trains on YouTube
Chris is working on a new board, the first time in a while
Abandoned scooters around Seattle have RPi4s in them
How did the 2n2222 get its name?
A new group of semiconductor companies (Bosch, Infineon, Nordic, NXP, and Qualcomm) join forces on RISC V
Former guest Mike Engelhardt releases a new spice version with Qorvo called QSPICE

Power Transmission with Toby Robb Jul 31, 2023

Show notes

Fellow Aussie Toby Robb joins Dave to discuss everything related to mains power generation and transmission and his role as a linesman.

Ask Toby a question here: https://www.eevblog.com/forum/amphour/im-linesman-and-electrical-fitter-in-powerline-distribution-in-australia-ama/

Links:

TransGrid’s substation design standard https://www.transgrid.com.au/media/zgogqoqg/1-1-substation-primary-design-standard-rev-2.pdf https://www.energy.nsw.gov.au/sites/default/files/2022-08/2019_10_NSW_ServiceAndInstallationRulesOfNSW_underlined.pdf

Software Defined Power Supplies with Werner Johansson Jul 25, 2023

Show notes

Welcome Werner Johansson of Qoitech!

Chris and Werner met when Werner gave a talk at HDDG in 2017
The talk focused on Xmega parts, which have a 2 Msps ADC
Qoitech is a Sony spinoff, where Werner was working on testing batteries on the cellphones.He had previously also worked on automation during linux mainline work.
Serial port control is an important thing when doing automated testing
CDB assist
PSOC5-LP has a CPLD in it
The Otii Arc was the first product from Qoitech, it's a 2 quandrant power supply. They started in 2015/2016.
Chris asked if Werner had previously had used the Keithley 2306
Field testing is an imporant area for the Otii product line. "Measuremenets on the go" are easier with the extruded case form factor.
No computer will give you USB PD output power of more than 15W. Test equipment would benefit from a full 200W
Analyzer (Twinkie?)
A hub might be possible
USB Extended Power Range (EPR) will allow 240W
Are you sure you should plug that into your computer? Reminder about the OMG cable discussed on the show with MG
New EPR at 48V has specific shape for arcing
When designing a power supply for tattoo machine, it could only weigh half the weight of the cable (64g)
Software defined buck boost was discussed on CNLohr episode
Digital control is easier to get stable than analog because of programmable delays in the pipeline. You need to measure how long it takes to get the output to "show up"
Audio project real time jam sessions
The new product from Qoitech (that Chris got to see at Embedded World in 2023) is the Otii Ace
PJRC convinced Werner to check out the NXP RT106x family (instead of RT105x)
Otii is working on battery stuff
Arc has been out since 2017, but was limited output voltages 500 mv - 5V
Ace came out recently and goes up to 25V at 5A
3 isolation domains in Ace - chassis, banana jacks, expansion ports
Want resistor on low side for coloumb counter
Can stack Aces up to 200V
Dealing with RFI when different domains
Increased sample rate
8 simultaneous sampled ADCs
Turns readings into audio signals for RT1060, which allows data to stream easier
There is one reference voltage driving everything in the design, they send frequency spike across gaps to all isolated sections using RF isolators
Hard time getting the RT1060 parts during shortage
Battery stuff
Stepping through the battery internal resistance
Edging into the world of SMUs
Building a curve
Replaying battery data
Battery emulation
Continuous integration testing
Syncing to firmware
Battery aging
Devices running on coin cells
Cycling and automated testing and see it degrade over time
Thinking of batteries as impedance devices
Batteries having a passivation layer
"Low power" means different things to different people
Teardown of battery emulator
Low power is less than 200W
Qoitech equipment has been used in testing and production, including "in-the-loop" testing
"Generational degrade" when using previous versions of the product to validate new versions of the product. Instead they have a NIST traceable DMM in the loop
Chris mentions ever calibration shop has a Fluke calibrator. Apparently the HP 8753 wasn't available in EU because of RoHS.
To learn more about Werner and the Qoitech team, check out the Otii Ace page

Daaaamn We're Duuuummmb Jul 17, 2023

Show notes

Dave has been traveling around Australia with family. He made a video about an old solar thermal facility.
Chris also has been traveling, he gave a talk at the Embedded Open Source Summit about doing embedded training.
Solar thermal efficiencies
What is the efficiency of a mirror?
What is the efficiency of a transformer?
Power engineering class
Nic Bingham giving a talk about high pressure electronics
Chris was inspired from CNLohr's episode where he talked about building a switcher. He recently bought a bunch of CH32V003 parts.
WSJ article about Chiplets (Archive)
Chiplets have been mentioned on the show a bunch before
- Ming Zhang
- Craig Bishop
Dave reviews the Analog Discovery 3. This is Chris's daily driver at this point, especially when on the move.
While searching for something during the episode, Chris stumbled onto an old reddit post from 9 years ago about how they decide where to build fabs.
Chris and Dave both felt dumb while watching Shahriar's Starlink teardown
Kathy Loves Physics will be doing videos about Maxwell's equations

Building AR Headsets with Aedan Cullen Jul 09, 2023

Show notes

Welcome, Aedan Cullen!

Chris first learned of Aedan from his 2022 Hackaday talk about building an AR system
AR is "Augmented Reality", but that term is different depending on the company / headset (think "magic leap" vs "google glass")
Got into AR because of robotics, he had be doing software around SLAM and CV
Interacting with objects in 3D space
The first board he was working with was the Jetson TK1
Magic Leap's "Lightpack" had a Tegra in it
Apple's new Vision Pro is more like VR with passthrough (and creepy eyes!)
Being able to wear an AR unit all day
Resolution matters
What is it worth spending power on in a headset?
The previous rev used the AllWinner D1 RISCV and can support one camera
Which way should you point a camera on a pair of glasses?
MIPI DSI outputs and DSP processing
Lots of SIPs available for high density designs
Octavo makes SIPs out of other companies' silicon.
Jason and Robert from BeagleBoard talked about Octavo when they were on the show
ECX337 from Sony needs 10V
Torex power modules helped save space too by being stacked on top of the inductor
Sony uses LVDS (FPDlink) and not MIPI
Offloaded processing to a phone or computer
Power
Wi-Fi vs bluetooth
New goal is to minimize power during processing, now it'll be efficiency around WiFi and Display
With OLEDs you can selectively turn on pixels
Goal for the battery is 8 hours for "all day"
What is Aedan's "requirements space" and what's driving it?
Cost has become a concern for new boards
Using an assembly house to have one known-good assembly board
What's on the new board?
- The new display has MIPI DSI
  - The display doesn't support 2 lane DSI out of the box
  - Displays are sometimes configurable in terms of how many lanes with registers
  - What do the lanes refer to? Each pair ("Data lane") is a differential pair
  - Most displays will do 4 lanes (8 conductors) at 1Gbps
  - "Giganibbles per second"
  - Silicon backplane with OLED on top
  - ViewTrix
- The processor is the NXP iMX RT500
  - "This is design is made for Garmin"
  - Aedan is coding it in Zephyr
  - Drivers are in MCUexpresso
  - DCnano display driver in Zephyr
  - no GPU driver in Zephyr
  - 2D GPU in the chip
- WiFi module is the same as the past rev, the Si Labs WFM200S
  - Sending compressed data over the WiFi link
- Mechanical
  - Tweaking displays and 3D printed mounts
  - Prism
  - Flex cables
  - XReal / NReal
  - Using your brain as the combiner
Zach from Voidstar
Aedan just went to the Augmented World Expo in May. "No one was wearing an AR display around the conference"
Vision for the future
Follow Aedan online
- GitHub
- Twitter

CH32V003...fun! with CNLohr Jun 25, 2023

Show notes

Welcome to the show, CNLohr of the YouTube channel of the same name!

CNLohr has been working on projects and a library for the ch32v003, the $0.10 RISC V part
Dave has made a video about that part, using the official toolchain from MounRiver
How far will you take the chip?
Moving from knowing the arm instruction set to the RISC V instruction set
The benefits of knowing assembly
The CH32V003 is a RISC V part in the low end space made by WCH. CN thinks it's about eqiuvalent to an AVR
You can buy a dev board on Tindie (this is the one Dave and Chris have)
Compiler tooling is done for you
AVR GCC
While discussing Espressif entering the market the way in which they did, CN said, "There's only going to be one of these in all of computing"
Community reversing esp8266 using a virtual machine that had a leaked toolchain on it.
Compared to cc2500 / mediatek / realtek
ESP8266 without an RTOS "nonOS SDK"
lwip and wifi stack
Community port of FreeRTOS onto the ESP8266
CN worked on the "NoSDK 8266"
It didn't have the WiFi enabled which meant timing wasn't critical and he could overclock it to 380 MHz
Minecraft on a microscope slide
Ethernet on an AVR
Other people in this space
igor plug
lwusb is massive (relative to the space on the CH32V003)
What about the support burden of writing things yourself?
Chris made a comparision to college
USB on CH32v003
CNLohr already had hardware on hand for decoding and debugging the USB stack
He livestreamed the development!
Chris said he was not sure he could livestream, but CN said that the audience acts like rubber ducks and pair programming
ESPUSB
vusb on avr
Does communicty work like this have an influence on the market?
Padouk 3-8 cent micro
Grainuum library (later figured out it was written by past guest xobs!)
lufa / tinyusb
What are the physical requirements to implement USB without a transceiver? Only real thing is you need a pullup on the USB D- line
You also need to change pins from intput to output in the window of responding
Can make HID devices, but everything is low speed USB (1.5 Mbps)
CN built the Nixie tube controller
On GitHub there are examples on how to use various aspects of the part
The chip has DMA
During the chip shortages, CN was browsing lcsc and found a 10:1 transformer and wondered if he could make a flyback with it
Single wire debug
Check out the CH332V003fun library on github
Getting started
The next few months CN will be working on getting everything to be really good for the library
There will also be support for other (larger, more expensive) parts
Join the Discord! (cnlohr)
Follow CNLohr on YouTube

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