The best-practice wind tunnel (above) vs a compact version (below)

Optimizing A Desktop, 3D Printed Wind Tunnel

You’ve heard of wind tunnels– get some airflow going over a thingy, put some some smoke on, and voila! Flow visualization. How hard could it be? Well, as always, the devil is in the details and [toast] is down in there with him with this Hot-Wheels sized wind tunnel video.

To get good, laminar flow inside of a wind tunnel, there are important ratios to be followed– the inlet and outlet diameters must relate to the interior size to get the correct slope on the contraction and exhaust cones. You need a flow straightener on both ends. All of it can be easily 3D printed, as [toast] shows, but you have to know those design rules and pay attention to, which [toast] does… this time. One of his “don’t do this” examples in this video is previous build of his where he did not follow all the rules, and the difference is clear.

Now, unless you’re hooked on flow visualizations —guilty— or are a Hot-Wheels aficionado, since that’s what this wind tunnel is sized for, you probably won’t rush to gumroad to buy [toast]’s STLs. On the other hand, if you pay attention to the lessons [toast] has learned in this video you can apply them to wind tunnels of whatever size and construction technique you need, be it cardboard or junk box plastic and get a more stable result.

Continue reading “Optimizing A Desktop, 3D Printed Wind Tunnel”

Smart Home? Make It Smart Quarters With This LCARS Dashboard

At the risk of starting a controversy: is there anyone who goes to the effort of setting up Home Assistant who wouldn’t really rather be living on the Enterprise-D? If such a person exists, it’s not [steve-gibbs5], who has not only put together a convincing LCARS dashboard on an Android tablet, but has also put together an easy-to-follow Instructable so you can too.

Continue reading “Smart Home? Make It Smart Quarters With This LCARS Dashboard”

M8SBC-486 Is An FPGA-Based “Kinda PC Compatible” 486 SBC

[Editor’s note: We got this one wrong! The computer uses an actual 486: the FPGA is running essentially as the chipset, interfacing the RAM and the ISA bus with the CPU. And since this went to press, [maniek-86] put out a nicer writeup of the project, which you should go check out, in addition to the GitHub link below.]

 

Given the technical specs of the FPGAs available to hobbyists these days, it really shouldn’t be a shock that you can implement a relatively-modern chipset on one, like one for a 486 system. In spite of knowing that in the technical sense, we were still caught off guard by [maniek-86]’s M8SBC project that does just that– the proas both CPU and BIOSducing a 486 FPGA chipset with a motherboard to boot.

Boot what? Linux 2.2.6, MS-DOS 6.22 or FreeDOS all work. It can run DOOM, of course, along with Wolfenstien 3D, Prince of Persia, and even the famous Second Reality demo– though that last without sound. [maniek-86]’s implementation is lacking direct memory access, so sound card support is right out. There are a few other bugs that are slowly being squished, too, according to the latest Reddit thread. Continue reading “M8SBC-486 Is An FPGA-Based “Kinda PC Compatible” 486 SBC”

The blower and a smaller motor than what's actually driving it.

Electric Snowblower Clears The Way With Hobby Parts

If you live in snow country and own a home, you either have a snowblower or wish you did. The alternatives are either an expensive and potentially unreliable plow service, or back-breaking (and heart-attack inducing) shoveling. [RCLifeOn] was one of those people in the second category, until he decided to do something about it: electrifying a scrap snowblower with a blown engine. 

The usual brushless DC motors and electronic speed controllers [RCLifeOn] has on hand to get his R/C life on with don’t quite have enough oomph to handle both functions of a snowblower. For those of you cursed to live in warmer climes, the modern snowblower is both self-propelled via its twin wheels, and generally has a two-stage powered snow-removal “blower” consisting of an auger to break up the snow and an impeller to blast it out of the machine and many meters off the driveway. On the traditional gas-powered models, these are both powered via belts off the same motor, but that wasn’t going to work.

He kept the belts, and simply used a pair of motors, each with their own ESCs that are controlled via oversized thumb wheels on the handles. The belts couple to the motors with 3D printed pulleys. Belt tension is achieved in the case of the wheels through a simple and sensible shimming arrangement. In the case of the blower motor, he uses a 3D printed adjustable mount to get the appropriate tension. To help it hold long-term (given the issues with creep in 3D prints) he’s got a bearing on a second mount opposite the motor.  It holds up for his demo, which consists of clearing a driveway of 10cm of snow and then plowing through a pile larger than the mouth of the machine. In other words: it works.

The build, as unfortunately common on YouTube, is shy on specific details– but in this case that’s fine. Even if he’d open-sourced everything and posted STEP or STL files, it wouldn’t save much time since you’d pretty well have to re-engineer the build to fit your own snowblower, if you were so inclined. As with many hacks of this nature, the point of sharing it is to show how easy it is and provide the inspiration. As the cartoons used to say, “knowing is half the battle.”

If one was to re-implement this hack, we could not encourage you strongly enough to put in the standard dead-man’s switch, a feature commercial snowblowers share with things like lawnmowers. As annoying as it is to hang onto with frozen fingers, that safety feature is there for a reason.

If your driveway is short, you can save on gas and fuel costs with an extension cord. Or you could just stay inside and do the job by remote control, but that comes with its own pitfalls.

Continue reading “Electric Snowblower Clears The Way With Hobby Parts”

The clock demo on display

Drive 1024×600 Pixels Via I2C With An ATtiny85

If you need to drive a big screen for a project, it’s fair to say your first thought isn’t going to be to use the ATtiny85. With just 512 bytes of RAM and 8 kilobytes of flash memory, the 8-bit micro seems a little cramped to drive, say, a 10″ screen. Yet that’s exactly what [ToSStudio] is doing with TinyTFT_LT7683: 1024 x 600 pixels of TFT goodness, over I2C no less.

With the right TFT controller, this little micro-controller can do magic.

The name kind of gives away the secret: it won’t work on just any TFT display. It’s using properties of the LT7683 display driver, though if you don’t have one of those, the RA8875 is also compatible. Those drivers can take more than just a pixel stream– a good thing, since you’d be hard pressed to get that many pixels streaming from an ATtiny. These are character/graphic display drivers, which means you can get them to draw both characters and graphics on the screen if you speak the lingo.

It’s still not blazing fast; the documentation suggests “static or moderately dynamic UIs” as the suggested use case, and a clock is of the pre-programmed examples. From that, we can surmise that you can get 1 FPS or better with this code. You’re limited both by the simple micro-controller and the bandwidth of the I2C bus, but within those limits this seems like a very powerful technique.

This isn’t the first ATtiny graphics library to blow our minds, but if you really want an impressive graphics demo from the little micro that could, you really need to race the beam.

Thanks to [Thomas Scherer] for the tip!

The modified hot glue gun, reassembled

Tired Of Burnt Fingers? Try PID Tuning The Hot Glue Gun

Hot glue guns are pretty simple beasts: there’s an on/off switch, a heating element, and a source of current, be it battery or wired. You turn it on, and the heater starts warming up; eventually you can start extruding the thermoplastic sticks we call “hot glue”. Since there’s no temperature control, the longer you run the gun, the warmer it gets until it is inevitably hotter than you actually want– either burning you or oozing thermoplastic out the tip. [Mellow_Labs] was sick of that after a marathon hot-glue session, and decided to improve on his hot glue gun with PID tuning in the video embedded below.

PID tuning is probably a familiar concept to most of you, particularly those who have 3D printers, where it’s used in exactly the same way [Mellow_Labs] puts it to work in the hot glue gun.  By varying the input (in this case the power to the heater) proportional both to the Parameter (in this case, temperature) as well as the Integral and Derivative of that value, you can have a much steadier control than more naive algorithms, like the simple “on/off” thermostat that leads to large temperature swings.

In this case [Mellow_Labs] is implementing the PID control using a thermistor that looks like it came from a 3D printer, and a MOSFET driven by an RP2040. Microcontroller gets its power via the hot glue gun’s battery fed through a buck converter. Since he has them, a small OLED screen displays temperature, which is set with a pair of push-buttons. Thus, one can set a temperature hot enough to melt the glue, but low enough to avoid oozing or third degree burns.

He does not share the code he’s running on the RP2040, but if you are inspired to replicate this project and don’t want to roll your own, there are plenty of example PID scripts out there, like the one in this lovely robot. No, PID isn’t reserved for thermostats– but if you are controlling heat, it’s not reserved for electric, either. Some intrepid soul put built a PID controller for a charcoal BBQ once. Continue reading “Tired Of Burnt Fingers? Try PID Tuning The Hot Glue Gun”

The clock and the rebuilt calculator from which its VFD was donated.

An RPN Calculator And A Bonus VFD Clock From Casio Revival

Have you heard the saying “the problem is the solution”? It seems to originate in the permaculture movement, but it can apply equally well to electronics. Take the problem [shiura] had: a Casio Mini CM-602 that had let out the magic smoke. The solution was a twofer: rebuild the Casio into a modern number cruncher with Reverse Polish Notation (RPN), and save the Vacuum Fluorescent Display (VFD) for a gorgeous WiFi clock.

[shiura]’s write-up includes a helpful guide for reverse engineering the pins on this sort of VFD, if you don’t happen to have the same model calculator (or VFD tube) they’re working with. If you’ve done this sort of thing, you know what to expect: power it up and kill power to the pins, one by one, to map out which segments or characters go out, thereby identifying the anodes and grid electrodes. The cathodes had already been ID’d from looking at the PCB. After that it’s just a matter of wiring the VFD to an ESP32 via a transistor array to get the voltages right, and voila! Clock. The code and case design files for this clock — including an editable .blend — are available via GitHub.

The calculator half of the project is an incredibly elegant hack that relies on the fact that the Casio’s CPU has the same pin pitch as modern micros: 2.54 mm, or 0.1″, so an RP2040 zero can sit in the footprint of the original CPU, scanning the keypads with its GPIO. Then an I2C display is separately wired up to replace the clockified VFD. Perhaps some driver circuitry for the VFD died, or [shiura] salvaged the display before deciding to save the calculator, because otherwise we see no reason why this brain transplant couldn’t be done while keeping the original display. Admittedly having two lines on the display instead of one make the “new” calculator a tad more usable. The code for that is also available on GitHub, and while the readme is in Japanese, machine translations have gotten pretty good and the code is quite readable on its own.

Longtime readers will likely be familiar with [shiura]’s work, with a number of finely crafted clocks having been featured from the Japanese maker, along with vintage pocket computer repairs. Bringing both together makes this twin hack particularly on-brand.

Continue reading “An RPN Calculator And A Bonus VFD Clock From Casio Revival”