What's New...

January 9 2023: A few months ago, I caved and bought an expensive kit to build a 60% scale PDP-11 replica: the PiDP-11PiDP-11. It was designed to use a Raspberry Pi running SIMH. However, the developer, Oscar Vermeulen, indicates that it is possible to use a FPGA module to emulate the PDP-11 in hardware.

This separate project uses a CYC1000CYC1000 module, which has an Intel/Altera Cyclone 10 FPGA with 25K logic elements and a nice USB programming port. And the development tools are free. And appear to run under Linux. What a fun toy!

I would much prefer to have a PDP-11 running as an emulation than as a simulation with boring old ARM instructions actually being executed. It's the next best thing to having a LSI-11 executing actual PDP-11 instructions.

Unfortunately, it seems that the demand for semiconductors that so hugely outstrips the present supply has made the CYC1000 unavailable. In discussions with the Arrow tech rep, it seems there is a 26-week lead time. He tells me that FPGAs are so dear that people were (are?) buying dev kits and removing the chips. But he assures me that the CYC1000 design is still viable, and I should be able to get on the 26-week waiting list. He is also going to look around for other FPGA modules that

  • Have at least 25K logic elements
  • Are programmable using free vendor-provided tools (hopfully that will run under Linux)
  • Have a module pinout like the CYC1000's MKR-compatible pinout that I could make a Raspberry Pi footprint adapter
  • Not so big that it won't fit in the available space in the PiDP-11's housing

I'm thinking that even if he finds some, they won't be any more available than the CYC1000, for the same reason.

So maybe I'll build the PiDP-11 I've already bought and received with one of my Raspberry Pi units and get SIMH running and put RT-11 or BSD Unix on it while I'm waiting for the ice to break on the Intel FPGA dam.

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Someone else has put a CYC1000 in a PiDP-11

December 10 2022: I got a notice from Digikey for a "training" (marketing) on-line lecture for the Arduino Portenta X8. I've got a few Arduinos, and we've used them in integration equipment, but I'd always thought of Arduinos as relativey cheap, limited, not really professional products, but "Portenta"... it was worth signing up for a one-hour video lecture by the Italian product manager.

Portenta X8It's a grown-up Arduino. Seems Arduino has multiple divisions, and what we're all familiar with is the low-end "Classic" series (UNO and the Mega and such). Seems there is a relatively new MKR series with a ARM Cortex-M0 (SAMD21). The big thing about the "Classic" boards is the more-or-less consistent expansion connectors (stackable headers), mimicked by many other vendors in order to share in the Arduino "shield" ecosystem. The MKR departs from this standard. But Arduino has a "Pro" division, and the Portenta X8 is the flagship. It doesn't have stackable headers at all, but two high-density mezzanine-style connectors on the back. The Portenta X8 has a NXP main quad-core microprocessor and a ST dual-core microcontroller, and oodles of I/O and peripheral power. The main port is USB-C. It runs a Yocto embedded Linux, and the applications run in Docker containers. It's targeted at the IoT market (what isn't, anymore) and so WiFi and Bluetooth are built in. Arduino is getting into the IoT world and has their own Cloud service (of course).

Pretty cool. Like a hopped-up Beagleboard. The connectors are a bit of a letdown; to get anything off, you have to have a carrier or breakout board (which Arduino has). The big downer is price: $239. And the breakout board is another $55. Interesting, but that's a pricey toy.

The Arduino "Pro" family also has the Portenta H7 with a dual-core ST microcontroller. Not Linux-capable, but more powerful than a Cortext-M0. It has a MKR-compatible stackable-header feature and also the Portenta high-density connectors on the back. So it's essentially a crossover. It's $114.

So... interesting, but I think I'll skip the Arduino Pro line for now. I might look into the MKR series, which actually has a growing portfolio of shields (and there's a MKR2UNO transition shield to allow the use of "Classic" shields). A basic MKR WiFi 1010 with Wifi and Bluetooth is around $40. That's more manageable.

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While poking around DigiKey, I discovered that they are carrying the Seeed Studio XIAO devices, such as the SAMD21, RP2040, ESP32-C3, and nRF52840 based tiny computers. That use Seeed's interface and are not obviously reprogrammable. Still... $6...

September 22 2022: I've started a new project at work for Bluetooth Low Energy (BLE) that uses a Fanstel BT840 module based on the Nordic nRF52840 device. I'd done a nRF52832 project maybe a year ago, got familiar with Nordic's Software Development Kit (SDK), and was expecting to reuse some code from that project. Lo and behold, Nordic has completely revamped their SDK to make the Zephyr Real Time Operating System (RTOS) the central feature. Can't reuse any code from old projects. But after going through the tutorial and seeing how I can pick and choose features from the Zephyr library, it's not so bad. Better in many ways than the mish-mash that the older Nordic SDK was.

About the same time, I had signed up for a Digi-Key on-line training event about "Embedded Systems". It was a brief thing, but I got a Digikey link to an "official" ARM education course on developing for ARM hardware. Digikey of course has a kit for the lab exercises based on the STM32 Cortex-M4 device. The course features the Mbed RTOS which is the "official" RTOS of the ARM organization.

Also about the same time, I signed up for Silicon Labs "Works With" conference, looked at their interesting BGM21/22/24 families, their development system (Simplicity Studio) can run under Linux, and it seems they officially support Mbed OS. At least, that's what I picked up in some lecture I watched (on-demand; I could not participate in the sessions as they happened during the working day). When I go to the Silicon Labs site and search for mBed or RTOS, I get a bit about mBed. On the other hand, when I look at Resources -> RTOS, I see "FreeRTOS" (that's good), "Amazon FreeRTOS", "Micrium OS", and "Asure RTOS", but nothing about Mbed. If Mbed is the "official" ARM RTOS, I'm a bit surprised they don't emphasize it more.

Mbed is just one of many RTOSes that are targetted at ARM. Besides Zephyr and the ones that Silicon Labs support:

There are lots more (presumably the list on Wikipedia will be kept current); these are the ones that are most interesting to me at this time.

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The labs at the conference, at least the MAT-301 "Design for Matter with the MG24" (the EFR32MG24 is perhaps the most interesting device, as it seems to support all the RF protocols except WiFi) have hardware requirements, which apparently got shipped gratis to people who registered far enough in advance. The components for the lab include a Raspberry Pi 4 (fair enough, except they're out of stock everywhere) and two radio modules. The lab manual specify the BRD2703A or the EFR32MG21 USB Stick, but says that the BRD4186C or BRD4187C can be used. The "hardware requirements" document in the lib Github repository includes a bunch of MG12 boards (not so interesting), explicitly states that the BRD2703A is not yet available (the USB stick gadget is apparently not available yet either), and mentions the xG24-DK2601B, which is available (for $79 at Digi-Key and Mouser).

The radio modules must be used with a WSTK mainboard such as the SLWSTK6006A. But the SLWSTK6006A is a "starter kit", includes THREE WSKT mainboards and a number of BGM21 modules (I don't want BGM21 modules) - For $479. Owie-ow-ow. There doesn't seem to be a way to get just a mainboard. Maybe the mainboard in the Pro Kit is the same as the WSTK, but it doesn't say (no part numbers). The User Guide says the radio board plugs into the Wireless Starter Kit Mainboard (BRD4001A) or the Wireless Pro Kit Mainboard (BRD4002A). So they're not the same. The User Guide also says that the drawings, including the schemos, are available on the "kit page" on the main site page, but there is no such thing. Oh, wait, silabs.com -> Resources -> Technical Library -> Schematics and Layout Files; search for "WSTK" and there's the BRD400A and BRD4002A. Looking at the schemos, no, they're not the same, but they may be close enough for the lab. BRD4002A is more complex and has an analog joystick and a USB-C connector, versus BRD4001A that has a USB mini-B connector.

The $79 xG24-DK2601B is based on a EFR32MG24 chip, but all the devices listed on the EFR32MG24 page list only the $179 Pro Kit as a dev kit.

Let's just say I'm not thrilled by the quality or consistency of Silicon Lab's website.

So what is so special about this MG24 dev kit that it's so pricey?


Wow. Two microphones. An IMU. Light, pressure, temperature, and humidity sensors. Even a Hall-effect sensor. What a busy board! Lots of playing with this one!

(The class using the STM32 eval board is pretty interesting, but I'm already wound up with the ESP32 things which I already have, and I need to learn another dev system like I need a hole in my head. However... I notice there are some wireless STM32 devices that support BLE 5.2 and WiFi and Thread and Zigbee, just like the SiLab MG24...)

September 5 2022: This past weekend was the Tucson ComiCon. They've been shut down for the Wuhan virus panic for the last two years, so this year was a restart. I think it showed in the sort of guests that came and the paucity of panel topics.

We came for all three days, and were exposed to unexpected implications of the Convention Center:

  • Parking is insufficient. There was a ridiculous line from Granada trying to get to the southwest surface lot. I took Jerri in that way to drop her off at the main lobby but was unable to merge into the line for the lot, so I went back out. There is a new parking garage behind the Music Hall, but it was apparently already full and blocked off. There is also a new parking structure on the northwest corner next to the hotel. There was a long line for that one, too. I'm not sure that the parking structure added as many spots as were lost to the new hotel and traffic routing. Plus, the cathedral across the street was selling parking spots. Everything was full. I guess this indicates how popular the ComiCon was, and that's a good thing (seems the Sugar Skulls were playing at the TCC on Sunday, not sure how much parking demand was due to their game). So I had to park at some distance away and walk over.
  • TCC management has new burdensome "security" restrictions. Only transparent bags and backpacks. Purses have to be of the small sort. We didn't know all this before arriving, so I had to walk all the way back to where I parked the car with Jerri's now-illegal purse. But no metal detectors. No inspecting costumes (beyond the usual "peace bonding" for verifying prop guns are not real). I don't know how the TCC management has convinced themselves that these "precautions" are going to prevent even mildly determined assailants. Mosty, they just make things difficult for legit attendees.

At any rate, the Con was lightly attended on Friday but Saturday and Sunday were flooded. Nice to see. Lots of cosplayers. But I missed the "steampunk" panel on Friday while I was walking the purse back to the car (and Jerri told me later that there was no "steampunk" panel on the boards of any of the (six) panel rooms, so they must have cancelled it). None of the other panels or spotlights were interesting - except one.

Jim ShooterJim Shooter started in comics at age 13, and at mid-70s he's still at it. He was Editor-in-Chief at Marvel in the late 70s when the comic industry was imploding, and managed to turn Marvel Comics around and into the powerhouse it is today. Of course, I didn't know any of this until the interesting septuagenarian was telling his story at the spotlight. We went back the following day for the "History of Marvel" panel. Yes, mostly his recollections of his time at Marvel (but like he says, his presence there overlaps with most of this history of Marvel), but he explained how the comic book industry was born from the collapse of the newspaper comic strip phenomenon in the '50s, and how Stan Lee, Jack Kirby, and Steve Ditko were instrumental in the early days of Marvel Comics. It was so impressive how good his memory was of the artists, editors, and managers of the comic industry in the "Bronze Age". It was also illuminating when he explained how clueless Marvel executives were, and how frequently he was called "upstairs" to advise people who had "never opened a comic book".

jimshooter.com. Not kept up to date, but there's a wealth of insight, history, art theory, and opinion by a comic industry titan.

Well worth the admission to ComiCon.

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Another one bites the dust:

Bill Johnson's Big Apple Sign Bill Johnson was a radio personality in Phoenix in the fabulous '50s (some background here). Part of his legacy was a small local chain of "Big Apple" steakhouses. The original was on Van Buren Street, quite a ways east of downtown, and we dined there maybe twice after the others had closed and the writing was on the wall for the last one. It was in a scary industrial area and only lightly patronized, so it was no surprise when it closed.

Bill Johnson's BBQ Sauce Then I happened to notice "Bill Johonson's BBQ Sauce" on the shelf at Fry's. I switched over and got to enjoy the last relic of an Arizona legend. And it was pretty decent sauce.

But I was buying sauce a few weeks ago and it wasn't on the shelf. Not even a spot for it. I checked at Albertson's and Safeway; similarly absent. A hint on some site after a web-search suggests that the family has decided to discontinue it.

Big Bob Gibson's SignHow sad. Back to Big Bob Gibson's Award-Winning BBQ Sauce (from Decatur, Alabama).

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I came across some really illuminating articles about abiogenesis - the problems with the naturalistic development of life from non-life.

There are five (scientifically-observed) attributes or requirements for a living organism:

  1. Perfectly-pure, single-molecule-specific bio-chemistry. This is the foundation of the autopoiesis stack. This includes homochirality (all the bio-chemical molecules with "handedness" - two possible arrangement of the atoms - are all the same with no exceptions) but goes beyond it. A 100% pure concentration of these molecules is not possible given ordinary chemical reactions.
  2. Specially structured bio-molecules. There is a large variety of complex organic molecules in a working cell, such as proteins and enzymes, each one constructed exactly as required to function. The probability of even one of these molecules forming with this required structure by purely natural (i.e., random) processes is essentially zero.
  3. Functionally integrated assemblages of highly-specified molecules. The living cell is composed of a large number of molecular machines that perform specific functions - generating chemical energy, transporting components to parts of the cell, parsing the contents of DNA and RNA, etc. Highly-specific molecules formed of highly-specific components must be integrated in highly-specific structures for these machines to operate as required.
  4. Comprehensively regulated information-driven processes. The micro-machines must be networked with metabolic pathways and cycles to accomplish the purpose of the cell operating, reproducing, and performing its own function as part of a tissue. The movement and operation of all these machines is orchestrated by the information encoded into the DNA.
  5. Inversely-causal meta-informational strategies. This is the pinnacle, the actual autopoiesis. The cause for all this interoperating network of micro-machines is the purpose of the cell, to survive and reproduce, and this exists after the effect which is the micro-machine network. So, inverse causality. There has to be information about the information that builds and operates the machinery in order to preserve and direct this functional information. So, meta-information.

Each level of the autopoiesis stack relies on the previous level and cannot arise from it by properties inherent in the previous level, by natural laws, or by any reasonable probability.

I find this fascinating integrated account of the scientific impossibility of abiogenesis much more compelling than the separate concepts (such as homochirality) by themselves.

June 30 2022:Finally finished writing up our travelog for the November 2021 California Lighthouse Tour.

April 6 2022:I've recently come across something very interesting: The GreenArrays GA144A12.

  • 144 (yes; 12-squared) individual processors!
  • Each processor is a F18A: 18-bit word, a few words of RAM, a few words of ROM, and control over some I/O pins.
  • Asynchronous! That is, no clock. So, since they're small, they're extremely fast, with cycle times on the order of picoseconds
  • Also as a consequence, ultra-low power.

I'm reminded of the two PRU processors on TI Sitara devices as present on Beaglebones (I've just finished a Marcus Engineering job involving Beaglebones and PRUs). Except that the PRUs are slaved to the ARM master processor. More like the Parallax Propeller with eight "cogs" that interact through a central "hub" of shared memory and access control features. But this is 144.

The GA144x device is apparently intimately connected with the Forth language. Since GreenArrays was co-founded by Forth-father Chuck Moore, this is unsurprising, and clearly the F18A processor was designed to be optimized for Forth. The IDE for the device is "arrayForth", and it's free... but runs on Windows. Well, I can get Wine if I want to; apparently its track record for running under Wine is pretty good.

It seems GreenArrays doesn't really have any distributors for the product, so they sell it themselves - $20 each in a ten-pack. So $200 to get started with bare chips. GreenArrays also has an eval board, but it's $495. ouch. schmartboard with GA144A12I also see that SchmartBoard has a package deal of their 88-QFN surface-mount adapter with a GA144A12 for $34, so that is a much more attractive way to get single pieces. Assuming SchmartBoard can get them; looking at the comments, it seems that delivery has been a problem. My concern is this adapter. Per the engineering, the through-hole pins are on 0.1" centers but with staggered columns at 0.05". I should have known a 88-pin anything was not going to plug into a solderless breadboard. So I would have to lay out a circuit board to plug it into. Too bad it doesn't plug into a standard socket (and maybe it does, but the lit doesn't mention it).

The eval board is interesting in that it has USB ports providing serial connections for a terminal (and presumably the arrayForth IDE), external RAM, and a SPI EEPROM - and it appears that the GA144X is interfacing with all of this. With no on-board peripherals, just some of the 144 F18A processors twiddling their I/O pins in concert! Almost worth $495 just to see it.

Almost. It's very intriguing, but I need another processor diversion like I need a hole in the head.

Even more enticing when people write fascinating promo stories.

The other interesting thing is that this isn't a new development. Seems they brought the GA144x to market in 2011. The latest thing on their news site is from 2019. All the comments about it on all the boards seem to be from between 2014 and 2017. And still no distributors. So I don't know if this is really a thing or a very-interesting "also-ran" thing.

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I messed with Forth very briefly on the TI-99/4A. Stack processing, "reverse Polish logic". That's hard to get used to. But it's very compact and efficient, and it has been used "bare metal" on especially embedded controllers, acting as an Operating System. Seems there has been (maybe is) activity to get Forth running "bare metal" on Raspberry Pis. My impression of Forth was colored by what was then apparently the primary/only/preferred way of getting programs to run under Forth - the "screen" or "block". The little I've picked up about the state-of-the-art is that the "block" is receding and the use of regular files is taking over. Much more attractive.

List of Forth environments for various platforms. I knew about Forth on the TI. Seems there's a GNU Forth, but it apparently isn't an install option for Slackware.

List of Forth systems for various processors and controllers, including for RISC-V, with activity of just a couple months ago: Forth is still clearly a going thing.

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Another resource: List of open-source FPGA cores for various platforms. There's one 9900 project on the list, and I'm pretty sure there are more than one out there. Also some PDP-11 projects. And... a F18A core from GreenArrays. With a FPGA dev board, maybe you could make your own GA144A12!

February 19 2022:NE555It is the 50th anniversary of the fabulous 555 timer.

I've had several of these, some I pulled off salvaged circuit boards, but I'm sorry to say I never actually played with any. At the time, the big attraction was for a long-term (hours, days) timer, but the inaccuracies of using a RC charging stack wasn't that appealing. But the device is capable of so much more. There are all kinds of resources for learning how to use it and inspiration for applications. Just a casual search turns up:

January 16 2022: Before going on our December trip to Oklahoma, I needed to shut down the cooler and fit the heater for service. This involves getting an air filter. So I just got one off the shelf at Ace Hardware and brought it home, but just before I installed it, after taking the wrapping off, I saw this:

Filter with ModuleThere is a module attached near the middle of the filter, and the wrapper indicates that you can connect with Bluetooth on your phone to get status on the filter.

The orange module is made of fairly thick plastic with no evident vents, and was glued onto the mesh of the filter. No wires emerge from the case. After cutting/breaking the plastic away, I found a small approx 1in square circuit card.

Module CCA top viewModule CCA back view

Other than a crystal and a few Rs and Cs (and of course the dominating CR2032 battery holder), the only comoponent is that module, which more than likely includes a Nordic Bluetooth device and whatever peripherals determine air quality. I really can't figure this one out, because the device is encapsulated in the orange plastic housing and there's no airflow through the housing (unless it's coming in through the little slot where the battery activation tab comes out), and there wasn't any obvious electrical connection through the housing. All those gold dots are test points, and the pattern of six dots with the three through-holes is clearly a Tag-Connect attachment for the programmer. Maybe the series of gold stripes on the back is a capacitive sensor that would be minutely affected by particulates in the air outside the housing.

I'm sorry, but this is stupid. Some electronic gadget that somehow determines how dirty your filter is and tells you over Bluetooth. A filter that you are going to replace anyways when rigging your furnace in the fall. This amounts to a waste of a lithium battery and more gold and heavy metal going into the landfill. I'm sure I paid more for this "technology". I'm going to be more careful in the future.

And it's not hackable. The only thing I got out of this was the battery.

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I was cleaning up my Arizona page and my Electronics page to fix the state of downtown restaurants and electronics surplus places. It seems that Halted Specialties has sold out to Excess Solutions, and Excess Solutions needs to fix their website so that it's actually useful. It also seems that the End of an Era has arrived, and Weird Stuff has shut down, the legendary Silicon Valley surplus and salvage warehouse. Another victim of Google, indirectly, since Google has been buying real estate in the Valley to the extent that property values are too high for a small business to operate. I'm also very sad that Apache Reclamation in Phoenix has shut down, apparently because the long-time owner has retired and nobody wanted to take it up from him. Adios, great surplus hacker dealers! I'm so glad Elliott Electronic Supply is still with us, and has this past year opened up their very significant surplus/salvage operation. Not as big as Apache, and rather heavy on the aviation parts, but a joy to wander around in all the same!

November 29 2021: I've just posted my thoughts about marriage, sexuality, and "church culture".

October 21 2021: Jerri and I went on a vacation trip to Texas to see the Big Bend National Park, the Alamo, the Texas Capitol, the ICR Discovery Center in Dallas, and the lighthouses of the Texas coast. The travelogue is now available.

September 6 2021: My dad and stepmother live on their own in a senior mobile estate place. AKA, "trailer park", except their house is a manufactured house, not a mobile home. Since they live on their own, they bought into an emergency assistance service, MobileHelp, which includes some electronic gadgets that they can use to summon help if they get in a bad way. The service has recently sent them an upgrade kit, to replace the electronics that they got five or six years ago. Since they didn't need the old stuff anymore, Mom offered me the junk to use or recycle (since I know how to recycle electronic junk, now: Suburban Miners).

Of course, I had to take it apart to see if there was any potential for reuse. When I was a teen, I would scout the neighborhood, especially the alleys behind the television repair shops, and take all the discarded electronic junk I could find home and dismantle it. I've still got a fair bit of old TV stuff, some of it useful (like carbon composition resistors) and some of it not (like tuner dials and knobs). I still do this now, but the options are much thinner, with all the surface-mount stuff. So, let's see about this MobileHelp junk.

MobileHelp CBS2-01 Base UnitThe base unit is a largish counter-top set with two large buttons, a smaller button, an LCD display, and a speaker. There's a five-volt three-amp wall-wart (nice) permanently attached, and a USB Mini-B connector on the back.

Base Unit CCA Top ViewThe insides are very intriguing. There's a big wireless module upper left with a serious antenna, another antenna module upper right, and a big IC lower right-of-center (underneath the LCD display).

My first thought is, this is a beautiful bit of work, I wonder if it could be repurposed? I'll bet that USB port in the back will serve as a reprogramming interface. The unit part number is CBS2-01. An internet search turns up a useful FCC site with photos and a user manual and some other stuff, but of course not a schematic. In older times, you could go to services like SAMS Photofacts with at least some hope of finding some technical data. In today's world, everything is proprietary unless it is explicitly and intentionally made Open Source. Which of course MobileHelp is not. This pretty much puts the kabosh on repurposing it. With a considerable expenditure of time and money, I might be able to reverse-engineer this thing sufficiently to understand how the sections talk to each other... but my time and money is better spent elsewhere. I do not want to make this MobileHelp thing a new time-sucking hobby project. So we're back to stripping it down.

Base Unit CCA Back ViewBack view of the circuit card assembly. So far, I can definitely reuse the wall-wart, the 8-ohm speaker, and the LiPo battery pack.

Base Unit Main ProcessorBase Unit Bluetooth Processor

The big chip at the lower right-of-center is a Microchip PIC32MX470F512L-1/TL. That's serious processing power. Probably the USB port goes here, since a lot of 32MX parts have USB peripherals, and the MX470 is one of them. But there's no point in even trying to desolder even a 64-pin ball-grid or leadless-chip package; it probably wouldn't survive, and I probably could not reattach it to a board I designed - it would be cheaper/faster/more certain to buy a new 32MX470 if I were doing something like that. And more likely, to just play with a 32MX470, better yet to buy an eval board from Microchip. So there's just no point in trying. On the other hand, I might be able to remove and reuse that Winbond 25Q64FVIG Flash EEPROM below it...

The device connects locally via Bluetooth, and the wireless processor for this capability is a Texas Instruments CC2540F256 - which is apparently no longer supported by TI.

Base Unit GSM ModuleBase Unit SIM

The MobileHelp system is essentially an embedded cell-phone that calls their service if you summon them. This u-blox SARA-U290, and its companion soldered-on SIM, is the cellphone as well as likely the GPS receiver that locates itself and transmits that information to the service. Again, I would be unlikely to successfully remove the module and reuse it, versus the sure-thing of getting an eval board from u-blox. But not of the SARA-U290, which is already end-of-life. Another problem with trying to reuse scrap components or even repurposing hardware platforms when you can get the technical information - there are likely to be too many unsupported or obsolete parts.

Base Unit Temperature SensorOn the other hand, this TO-92 package of a standard Microchip MCP9700AE temperature-to-voltage converter is easily removed and reused.

Remote DeviceThe second tier of the service are these summoning remotes. My dad has a little belt pouch that looks like it's for a small flip-style cellphone, but it's actually his MobileHelp remote.

Remote Model 1 GutsThere are two remotes in the junk bestowal, and they appear to be two different models. I think this one is older. This is the back side of the board, opposite the 8-ohm speaker.

Remote Model 1 Main ProcessorRemote Model 1 GSM Module

The main processor is a Microchip PIC24FJ128-GB106. On the front side of the board is the main GSP cellphone module, a u-blox LISA-U120. u-blox does not even acknowledge the U120 model any more.

Remote Model 1 GSM ProcessorRemote Model 1 RF Section

For some reason, in addition to the big GSM module on the front, there's a smaller u-blox MAX-7C-0-000 on the back. This device, which is still available, is specialized as a GPS/GLONASS location receiver. I can't imagine why the big module couldn't do that. Right next to it is a SIM chip. Also on the back is some short-range RF module, probably not Bluetooth since the receiver is a superheterodyne Micrel MICRF211AYQS... which is not recommended for new designs. I was startled to learn that Micrel, long a major RF devices player, was acquired by Microchip. Note the cute printed-circuit antenna.

Remote Model 2 GutsHere is the top of the board of the other model. Both have very reusable LiPo battery packs and 8-ohm speakers.

Remote Model 2 Main ProcessorRemote Model 2 GSM Module

The main processor and main GSM module are on the front of the board. A PIC32MX470F512L-1/TL and a u-blox SARA-U260 - same as the base unit. Common parts are a good way to reduce inventory, which can lower costs. Probably a PIC32 is overkill for this application.

Remote Model 2 GSM ProcessorRemote Model 2 RF Section

On the back, the locator GPS receiver is a u-blox MAX-M8C-0-02, and the RF receiver is a Micrel (Microchip) MICRF219AAY (fully supported).

Remote Charging StandBoth models of remote device have a common package, which plugs into this charging stand. The wall-wart has a USB B-Mini on the end.

Charging Stand GutsCharging Stand Processor

I was shocked to see how much circuitry there is inside a charging cradle. This is way more then what just regulates a voltage to apply to the remote device in the cradle. That's a PIC18LF4550-1/PT. The fact that this PIC18 part also has a USB peripheral makes me think that the USB does more than just supply 5V to the cradle. I also note the five-pin header right next to the PIC - looks just like a programming header. Now, this board may be amenable to hacking... except, what would you do with a charging cradle?

Wristband DevicesLanyard Devices

The third part of the MobileHelp ecology are the local summoning devices. There are two kinds: a wrist strap device, and a lanyard (around the neck) device. These devices must just communicate with either the base station or the remote device, since there are no GSM cellphone modules or GPS receivers inside.

Device AssemblyDevice Assembly Guts

Both wrist strap and lanyard devices have the same guts, this tiny module with a membrane switch (under the white tape) and a lithium battery. There's only one active device on the board; it has a Microchip logo and an indecipherable part number, "1840T39A". It's a fourteen-pin chip, so it can't be a PIC12F1840 eight-pin microcontroller. There are obviously antennae connected to it, the printed-trace on the back and the "flex" strip soldered to the board. Unless these are both parts of the same antenna. I'm guessing the "1840" is a custom part made for MobileHelp that includes wireless capabilities.

Device BatteryNot much recoverable from the module. However, the battery had to be removed to see the insides of the module. Its non-rechargeable, so the wrist-strap and lanyard devices are one-time products. It appears to be a CR2032 with solder tabs. There's still 3V on these guys. I might be able to use them.

After looking at all this electronic junk, I can strip off a few things like batteries and speakers and a temperature sensor, but the rest will get a one-way ride to Suburban Miners. And all the plastic goes into the trash.

August 30 2021: The last installment in my series of thoughts about "church culture": What Fellowship Really Looks Like.

August 29 2021: The third installment in my series of thoughts about "church culture": Sunday School Could Be Better.

SVRBC LogoWhile I was doing research for this Sunday School article, I happened to come across the website for Silicon Valley Reformed Baptist Church. After getting over the astonishment that there would be an orthodox church in the San Jose valley, let alone a Reformed one, I noticed that their logo is a cross formed of... printed circuit board traces! How appropriate for Silicon Valley! How Christian Geekly!

August 27 2021: The next installment in my series of thoughts about "church culture": An Analysis of the Sermon.

August 22 2021: Too many toys.

I visited my friends at Marcus Engineering, and the part-time super-tech/self-employed lighting developer/hobbyist was telling me about his new preferred embedded control platform - the Espressif ESP32. Dual-core, gobs of peripherals, and... best of all... WiFi and Bluetooth. I had to look into this.

The top three models are the ESP32-D0WD-V3, the ESP32-C3, and the ESP32-S3.

  • ESP32-D0WD-V3 is the go-to product in full-rate production. Dual Tensilica Xtensa LX6 processing cores running at 240MHz, 520K RAM, 18 channels 12-bit ADC, two channels 8-bit DAC, 32 bits GPIO, 10 touch inputs, 3 UARTs, 4 SPI peripherals, an SDIO Host and SDIO Slave peripheral, two I2C, two I2S, an Ethernet MAC, a Hall-Effect sensor, and some other stuff. Like I say, gobs of peripheral I/O. The Bluetooth radio conforms to version 4.2 of the spec.
  • ESP32-C3 is also in full-rate production. Instead of dual Tensilical processors, it has one RISC-V processing core. That is extremely interesting to me, considering as the next TOW computing systems are going to be RISC-V. Not as fast (160MHz) and not as much memory (400K SRAM), but this may not compare well across different processor types (albeit both RISC). Not as much I/O: six channels 12-bit ADC, no DAC, 22 bits of GPIO, no touch, two UARTs, three SPI peripherals, no SDIO host or slave, one channel of I2C, one channel of I2S, no Hall-Effect, no Ethernet, and less of the other stuff. The Bluetooth radio conforms to the more recent and capable version 5.0 of the spec (5.3 is the most recent at this time). So, more interesting for the RISC-V and the enhanced Bluetooth, less interesting for the reduced peripheral I/O.
  • ESP32-S3 is not in production yet, but is sampling. Dual Xtensa LX7 cores at 240MHz, 512K SRAM. Different/more I/O set: 20 channels of 12-bit ADC, 45 (!) bits of GPIO, 14 touch inputs, two SDIO host interfaces, no SDIO slave interface (not sure what the use-case is for a wireless module having a SDIO slave interface), no Hall-Effect sensor, and it swaps the Ethernet MAC for a (probably more useful USB port. Like the S3, it conforms to Bluetooth 5.0. So, more interesting for the advanced Bluetooth and I/O set, less interesting for not being RISC-V.

ESP32-WROOM-32EYou don't really want to deal with the chips themselves. Bluetooth devices, and 802.11 WiFi devices, come in modules that have already gone through FCC and hopefully a broad array of international certifications. The workhorse module for ESP32-DOWD-V3 is the ESP32-WROOM-32E. It's got an on-board 4MB flash memory for program storage and an on-board 40MHz crystal, so all it needs is 3.3V power. All the I/O pins come to the castellated contacts on the surfaces. The module is intended to be surface-mount soldered to the user's PCB. Less than $3 from Mouser. Pretty Darn Amazing.

The ESP32-C3 is incorporated into the ESP32-C3-WROOM-02. Looks the same as the ESP32-WROOM-32E, but of course the pinout is different. Less than $2 from Mouser. Even More Darn Amazing!

It's not very convenient to mess around with surface-mount modules, so Espressif incorporated the ESP32-WROOM-32E into the ESP32-DevKitC-32E, a teeny circuit board with a USB-to-serial port for loading programs, a 3.3V regulator, and pins on 0.1" centers to plug into a breadboard. $10 from Mouser. That's still pretty good. Similar to the $4 Raspberry Pi Pico, but with different I/O and WiFi and Bluetooth.


Similarly, the ESP32-C3 is on a ESP32-C3-DevKitM-1. $8 from Mouser.

The ESP32-S3 will be placed on the ESP32-S3-WROOM-1 module and the module on a ESP32-S3-DevKitC-1, but they're not on the market yet.

I'm not in a hurry. I could get one (or two) of the ESP32-D0WD-V3 boards for the dual core and extensive I/O and one (or two) of the ESP32-C3 boards for the RISC-V and the Bluetooth 5.0, and play with them, get them to talk to each other, learn the tools. The price of the goodies is nothing compared to the time to learn how to use them and enjoy making them work.

Too many toys...

August 02 2021: The next installment: Is "Worship" Music Really Worship?.

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My dad had a few old Horatio Hornblower books by C.S. Forester. The story of fighting ships and the English civilization in that period was fascinating; I subsequently got the rest of the books in the series. I know there are people who fawn over the P. O'Brien series of Jack Aubrey and Stephen Maturin, but I doubt any similar story is going to top my first encounter with the genre.

I also read Richard Dana's classic Two Years Before the Mast, which was biography, an account of his experiences on a commercial ship to colonial California. Not fiction.

From whatever source, I've encountered Fitch Waterman Taylor, who was a commercial seaman and then a chaplain in the fledgling United States Navy. Taylor wrote out some of his experiences in books like Broad Pennant and A Voyage round the World. Biography, not fiction. After 200 years, the copyright on his works has long since expired and the books are long out of print, but fortunately they are considered Public Domain. I've discovered that scans of the books are available at Online Books Library. You just have to read the 664-page PDF of the image scans of the books on your computer!

July 31 2021: After a long hiatus, I've posted some long-simmering thoughts about Church Culture versus Christianity.

July 30 2021: Gearing up to put some more of my "Thoughts" about Christianity and the church on the long-neglected page. Prior to that, I've cleaned up and updated a number (well, all) of the Christian pages:

July 28 2021: This year, under the impression that the City had cancelled the firework show over "A" Mountain, Jerri and I took a weekend trip to Colorado.

  • Loveland and its sculpture gardens
  • Fort Collins' historic trolley
  • Fireworks over Lake Windsor

See the Family Page for the whole story!

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Once again, the concept of setting up a passenger train route between Tucson and Phoenix is back on the table.

I know I would ride it. Imagine packing an overnight bag (imagine Jerri being able to operate out of an overnight bag) and zipping up to the Big City for a day or two, catching the Metro at Sky Harbor and going to the usual haunts on Central. It would be better if the train were fixed to carry your automobile, but Amtrak doesn't do that.

I'm sure we couldn't do much more than an overnight bag. Looks like the Amtrak station at Sky Harbor doesn't deal with checked bags. Although interestingly enough, both Tucson and Flagstaff do, but I guess Tucson and Flagstaff are on big-name routes and the Capital City is not.

Also interesting, Phoenix is listed as a destination on the Sunset Limited line, but the train doesn't actually go through Phoenix, but rather the smallish town of Maricopa, 30 miles south of Phoenix and way off I-10. Obviously, Maricopa was more of a thing than "Pumpkinville" when the Southern Pacific built the line around 1880. Also, Phoenix is served by the Santa Fe line, same as Flagstaff, so you would think it would be easier to run a passenger route on BNSF tracks; however, the Amtrak page for Phoenix says the connection to the Flagstaff station is by van. I guess if Phoenix-Tucson is a hard sell, how much more Phoenix-Flagstaff?

I may be waiting a while, though. Amtrak being a federal government monopoly, it seems Congress has to allocate the funds. I suppose the way the current Congress is throwing money around with wild abandon, it isn't too much of a stretch to hope for this. And then it would be at least three years afer that to make it happen. Considering the pace of roadwork in Pima County, building a railroad would almost certainly be more than that.

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RasPadAs I was clearing out old stuff on this "What's New" page, I noticed a few Raspberry Pi-based notepad systems. It would seem one of them, the RasPad has made it out of the Kickstarter phase pretty well and has a product ready to ship. It's a kit, not a finished item, and the kit appears to lack the actual Pi board itself, but it looks like you can put whatever Pi model you want (so it's likely upgradeable as RasbPi produceds new models). I can't say I'm thrilled with the thickness, or the wedge shape, but I guess that would make it a convenient "digital picture frame" (although I'm still holding out hope for a successful passive color display technology rather than the ubiquitous "shine the blue light into your eyes" active display). Quite a few complaints about the noisy fan, too; I find it a bit disconcerting that a tablet or notepad even has a fan. The $219 price is okay.

We'll see. Lots of stuff to do and toys to play with right now.

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Raspberry Pi PicoAlso, while looking at the Raspberry Pi site, I noticed that in addition to the Linux-based single-board computers for which they are famously successful, they have introduced a custom-designed integrated circuit, the RP2040, a dual-core ARM-based microcontroller, and a platform to showcase it, the Pico. It's similar to the Microchip Curiosity dev boards I've been playing with in that it can present itself to a host computer as a USB Mass Storage device, and you can just copy the executable file to it, and upon reset, the file gets burned into program flash and executed. Lots of I/O and integrated ARM-style peripherals. And... It's $4.00!!.

The U.S. vendors, Sparkfun and Adafruit are out of stock, so it's clearly a hit. Both companies have also released versions of their own microcontroller platforms using the RP2040. Looks like this one is a winner.

July 18 2021: I have recently finished a quick-turn project: a thermostat controller for the evaporative cooler I've now had installed on my backyard workshop. 95% junkbox parts.

Cooler Controller boardPart of doing this projecxt was to brush up on the current gEDA and PCB (geda-project.org) and try out DK Red, the budget printed circuit board service provided by Digi-Key.

Finished project, mounted on the wall above my bench (so I can see the temperature) and connected to the high-voltage wiring with 3/4" conduit:

Finished controller, interiorFinished controller, exterior

I've also made the project available on the Microcontrollers page and its own Cooler Controller page, which has more details.