I'm doing some light steam bending here in the kitchen.
somewhere in this tube are a couple of oak boards and cut to shape. I'm going to clamp them down to the kitchen counter over a small form when I pull them out.
Obviously I don't do a lot of woodworking. Actually, it's pretty obvious that nowadays I don't do a lot of anything for the blog. It's not to say that I'm not keeping myself busy but the old days just aren't what they used to be. I'll chalk it up to having two beautiful little kids. They're awesome, but until they're about 5 or 6, there's not a whole heck of a lot you can get up to with them. The amazing thing now though, is that these pieces are for a little sailboat that we took out today. I'm teaching my kids how to sail. It's awesome. And that's something. Not to mention they're little builders too, and storytellers and performers. We have a good time together but we're not doing much CNC routing or programming. But there's time.
So this isn't an F-16 style afterburner, but rather a shadowgraph of air coming out of my air compressor (through the blow gun) made with nothing more than a single white LED as a point light source and my phone (and a wall, where the shadows are cast) There's a way more fancy and sensitive way to get these kinds of visualizations, called Schlieren photography which involves parabolic mirrors and a knife edge, but unfortunately my personal parabolic mirror happens to be in a telescope 3000+ miles away, so we'll have to just settle on Ikea lights and tape for the moment.
You can clearly see the standing waves as the air comes out. The pressure is only about 85 PSI, but you can see the shape and spacing change as I vary the flow. This sort of valve is not great at fine control, but you get the idea.
Mach diamonds, or shock diamonds are "a formation of standing wave patterns that appear in the supersonic exhaust plume" - thank you Wikipedia.
I'm mostly impressed that my air compressor goes supersonic .
Electric ATV - First run (spoiler alert, we have since fitted a jackshaft) and the results are a big bummer. Turns out, all of the low end torque that the electric motor had wasn’t enough for running in the equivalent of 4th gear. Not exactly a failure, but there was a slight smell of hot brushes and varnish after this run.
Do yourself a favor and play this at double speed. This is the first impressions of the 4-wheeler conversion, complete with my usual mumbling and cussing. And excuse the shop (garage) - It’s wearing a lot of hats these days and is jam packed with outgrown baby related claptrap. I’m kinda looking for actual shop space at the moment. The current state of the project has moved far past this point, with some discoveries that seem pretty obvious in hindsight. But I am undeterred, and the next steps are well underway.
After a long break, I think the Kontraptionist Lab is going to get back to work. There’s just too many signs stacking up, and they all say GO. So I’m going to start by converting this terrible little ATV over to an EV for my kids. Also, some client work came in - an old project, but a really awesome one. Stay tuned for more. We’re back, and acquiring tools! Sure, the mix of projects is going to be a bit different, and the frequency of posting will probably never reach their historical highs again, but it’s all going to be fantastic. And also in Los Angeles now. I can’t wait!
I’m putting my Renesola solar hacking project on Github for all to criticize.
https://github.com/DrFrankReade/ReneSola_MRG
Hopefully all those poor saps that got burned when the company vanished can now once again start talking to their hardware and getting stats and troubleshooting. And one day maybe I’ll python-ize it.
Adventures in home solar hacking!
I was on craigslist the other day, and found a real great deal on these solar microinverters. $50 a pop for a 250 watt capacity device is a great deal in most cases.
In case you’re wondering, a micro-inverter is a little box that attaches to the back of a solar panel and boosts the voltage and matches the frequency and phase of it’s output to match your home’s power, and pushes power back in to the grid, literally spinning your electrical meter backwards. You basically just plug them in and it goes. These things can go $200 a pop, and to find them for $50 is magical. This is the basics of a grid tie solar inverter. It first offsets whatever load you have in your house, literally stopping your electrical meter in it’s tracks and whatever is left over will spin the meter backwards and then gets exported out to your immediate neighbors, and if they can’t soak up the extra power, out to the greater grid it goes. So I hopped in to the car and met a dude at a storage unit and bought a pair of these microinverters from some no-name Chinese company called Renesola, hooked them to a couple of $100 panels the dude also had for sale (230 watts each!) plus another $20 in extra chingaderas to connect everything to the house, and I was off and running.
Hookup: The diagrams were shit, like most crappy Chinese no-name products, pixelated and printed too small, but they were sort of legible and the pictures made sense. L and N go to each hot leg of the 220, which should give anybody with half a brain some serious pause without a picture. N is basically ground in US electrical systems, though not technically, But the picture called for hooking it to a hot 220 leg, so fuck it. There were fuses and breakers and they were only $50. Then there was the PE wire. I had to look that up. PROTECTIVE EARTH. That’s what PE stands for. We call that one GROUND.
Now, let me be really frank here - The first setup was a little bootleg, coming in through the air conditioner power box. There were wire nuts involved. The inverters hook to 220, and the A/C is handy. Things like disconnects and maybe even fuses have since been added, so don’t do anything stupid at home (for very long or unattended)
Sure enough, the mechanical meter spun backwards. I don’t know what will happen with a digital meter - Maybe they’ll immediately call the fun police on you, who knows, but my meter is ancient and just fine.
So here comes the fun part. I wanted better performance monitoring, and some liquidator across town had a bundle of these monitoring boxes called the “ReneSola MRG Micro Replus Gateway ” that would talk to each inverter with “Power Line Communication” like the old X-10 devices, it basically superimposes data during the zero crossing (when the sine wave of your AC power is zero volts) and anything plugged in can talk during those very brief times. There are lots of different protocols for this, and Renesola does NOT use any of them. They use some rando chip called the Miartech MI200E, which appears to only be available on alibaba. Datasheets (in Chinese) can be found with a fair degree of hunting, but they’re probably of little use.
So I got this stupid box, which is a Linux box with a touch screen, 220V power input, USB and ethernet ports, that tries to connect to “The Cloud” which is some server in China that’s only referred to by it’s IP address, and it’s long gone. You can’t change it, and it’s pretty well locked down, despite the USB port and old versions of lightHTTPd running on it. I’ll post the results from a nmap session at some point. BUT, I don’t feel entirely comfortable with it on my network, but it’s not doing anything weird, plus I gave it a bad gateway address, so it’s probably going to have to work pretty hard to get on the internet.
You’d figure that with an Ethernet port, you could log in to it and get some web page for looking at statistics, but no. You get 404 errors. It’s got an SSH port open, but I wasn’t able to figure out the credentials. So, useless, but after some digging, and then backing up the device to a thumb drive, I discovered that it made a big old tarball with a directoy structure that started with root. So there was that. It started with root>Gateway>data>0>day.dat and a bunch of other files. And it just so happened to perfectly mirror the structure of the onboard web server. So putting in http://10.41.61.21/data/0/min.dat would download a file (on your own LAN of course) of minute-by-minute data that was literally every minute since midnight of that day. It looked like this, human readable and space delimited. And all day, it just appends more data to the end of the file, and overwrites every day at midnight.
So there’s Date,Time, kW, MPPT/DC voltage, AC voltage, AC amps, AC frequency, temperature, total kWh, RSSI maybe, mystery and mystery.
The graphs look great in Google Sheets when you import this data, so it’s working.
So my plan is to put this data in to an open source system called Homeassistant - which is a Raspberry Pi (usually) powered home automation hub, which as far as I can tell, is superior in every way to anything else out there. You can connect ANYTHING to it. Cameras, cars, every kind of smart device, thermostat, lock, TV, projector, server, web service, sensor, smart speaker, alarm system, zigbee, z-wave, you name it and you can voice control it. I run Homeassistant at my house and it’s fantastic. BUT IT NEEDS MORE DATA!
So now I need to learn python, and write my own integration and parse these files.
Now here’s the thing about Renesola. They’re GONE. That 20 year warranty? Gone with them. Check out their listing on the NYSE. So long.
And what I’m writing here is literally the only data out there that you’ll ever see on these devices unless some brave ex-Renesola IT soul should come forward with better information and keep these things useful for a few more years.
SO on to this HTTP directory structure. As follows:
.
├── data
│ ├── 0
│ ├── 1
│ ├── 2
│ and so on and so on
│ ├── 254
│ └── 255
├── ddata
├── mdata
├── total
└── ydata
In the numeric folders in “data”, you have files called day_base.dat day.dat hour_base.dat hour.dat min.dat min_tx.dat (with min.dat and min_tx appearing literally identical) Maybe other files are redundant too...
ddata, mdata and ydata have files called module0.dat thru module255.dat
and then in the total folder there’s two plain, extensionless files called
dayEnergy and energy
which is linux time, first line is the system total, followed by each panel on each line. Energy is the same data, but without timestamps.
As for these moduleX.dat files, I can’t really say. It’s linux time, followed by zeros, and terminating with some unprintable characters that I haven’t figured out. The backup I took was from the first day of operation, so maybe this isn’t fleshed out yet, and will probably look a lot different a few days in. Oddly, I can’t seem to make another backup, so I’m lucky to have picked this one up. More to follow I guess, as I perhaps write a Homeassistant integration.
"It's a thin line between pair programming and back-seat driving." #Multitasking Wanna join the carny family? http://twobitcircus.com/careers/ pic.twitter.com/6eqCzx4YQI
We made a cloud that rains tequila at Two Bit! This apparently is how the Mexican government thinks they’re going to convince Germans to vacation in Mexico. It looks good enough that it just might work. It uses ultrasonic atomizers bigger than anything you’ve ever seen - Like, the size of a cheesecake, and a COUPLE of them. The one in your home humidifier is about the size of a dime. We did several iterations of this, and lemme tell you... the shop smelled pretty boozy for a while, triggering mostly bad memories for our staff, and to make matters worse, it’s not like we used the fancy stuff for testing either.
See the cute article on IFLScience! (image above courtesy of)
There are many ways to cut metal. This way is called the Dry Cut Metal Saw which is exactly what it is. A big saw blade with carbide teeth that cuts through steel with no coolant or lubricant. It’s loud. Really loud, and it throws showers of hot burning metal shavings everywhere. It’s the less offensive sibling to abrasive saw cutting, although the metal shavings it makes are much larger, so they carry more heat, so they do a much better job of burning areas of carelessly exposed skin, and are also very effective at getting caught in socks and pockets. What it doesn’t do is fill the air with resin, aluminum oxide and fiberglass dust, which the abrasive saw does quite well. Let’s be clear. I do NOT like this saw. I also don’t like abrasive cutting either, but for really hard materials, sometimes an abrasive blade is the only way to go. For the most part, I’d much rather just use a nice horizontal band saw with coolant. It’s way more humane to the people around it, and they produce better cuts too. BUT when you’re in the middle of a parking lot, sometimes you just have to suck it up.
Today, I’m making blanks that will be machined and tapped to hold shoulder bolts and bronze bushings for a VR experience platform. Photos of that part of the job to follow.
CNC milled and programmed some stuff up for a project for JPL up in Pasadena. It’s a prototype for a moving sign post that points to celestial objects and tracks satellites in real-time. Pretty snazzy. It uses a simple Arduino (for now anyway) to control all the movement and a Teensy that’s eavesdropping on the serial line to cherry-pick out specially formatted comment strings in the movement instructions to change the text and color.... all crammed in to a 4″ pipe AND waterproof. Note that in this version, there’s no pipe covering the guts, and no custom circuit board has been attached, so nothing is weather tight yet. A fun project. I promise more in the near future.
It’s called Cymatics. A fun gadget to demonstrate standing waves and to drive everybody crazy with in the shop. It’s a speaker enclosure with a thin membrane, topped with some gross powdered drink mix because it was the only convenient powder we had that wasn’t hazardous. This was a prototype for a client job, intended to demonstrate that a 30 foot one of these would be so outrageously annoying that it would be rendered impractical. Ernst Chladni had his plates, I have my Saran Wrap.
Decided I finally needed to get my life together and get a nice boombox.
This one features two giant JBL speakers, an 800W Behringer mixer / amp / processor / whatever, all powered by a nice 1KW pure sinewave inverter, juiced by a hefty 24V electric lawnmower battery that I converted from god awful lead-acid batteries to lovely lithium iron phosphate (originally intended for electric car conversion)
This thing loitering around the shop this afternoon - Makes the whole place shake!
According to the wikipedia:
The Bell UH-1Y Venom is a twin-engine, medium-sized utility helicopter, built by Bell Helicopter as part of the United States Marine Corps' H-1 upgrade program. The helicopter is also called Yankee for its variant letter, Y
