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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-11 This separate project uses a 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
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. . . . . . . . . . . . . . . . . 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.
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. . . . . . . . . . . . . . . . . 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. . . . . . . . . . . . . . . . . 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:
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.
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. . . . . . . . . . . . . . . . . Another one bites the dust:
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.
. . . . . . . . . . . . . . . . AUTOPOIESIS "Self-making". 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:
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.
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. 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. . . . . . . . . . . . . . . . . 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. . . . . . . . . . . . . . . . . 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: 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:
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. 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. . . . . . . . . . . . . . . . . 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.
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.
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. 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.
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. 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.
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. 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).
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? 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. 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.
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.
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.
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?. . . . . . . . . . . . . . . . . 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.
See the Family Page for the whole story! . . . . . . . . . . . . . . . . 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. . . . . . . . . . . . . . . . .
We'll see. Lots of stuff to do and toys to play with right now. . . . . . . . . . . . . . . . .
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.
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: I've also made the project available on the Microcontrollers page and its own Cooler Controller page, which has more details. |