Author: Bryan Cockfield

835 Articles

Super 8 Camera Brought Back To Life

September 30, 2021 by 27 Comments

The Super 8 camera, while a groundbreaking video recorder in its time, is borderline unusable now. Even if you can get film for it (and afford its often enormous price), it still only records on 8mm film which isn’t exactly the best quality of film around, not to mention that a good percentage of these cameras couldn’t even record audio. They were largely made obsolete by camcorders in the late ’80s and early ’90s, although some are still used for niche artistic purposes. If you’d rather not foot the bill for the film, though, you can still put one of these to work with the help of a Raspberry Pi.

[befinitiv] has a knack for repurposing antique analog equipment like this while preserving its aesthetic. While the bulk of the space inside of this camera would normally be used for housing film, this makes a perfect spot to place a Raspberry Pi Zero, a rechargeable battery, and a power converter circuit all in a 3D printed enclosure that snaps into the camera just as a film roll would have. It uses the Pi camera module but still makes use of the camera’s built in optics which include a zoom function. [befinitiv] also incorporated the original record button so that from the outside this looks like a completely unmodified Super 8 camera.

The camera can connect to a WiFi network and can stream live video to a computer, or it can record video files to an internal SD card. As a bonus, thanks to the power converter circuit, it is also capable of charging a cell phone. [befinitiv] notes that many of the aesthetic properties of 8 mm film seem to be preserved when using this method, and he has several theories as to why but no definitive answer. If you’d like to take a look at some of his other projects like this, check out this analog camera that is now able to take digital pictures. Continue reading “Super 8 Camera Brought Back To Life” →

Erasable Pen Ink Adds Colors To 3D Prints

September 28, 2021 by 8 Comments

Changing colors during a 3D print is notoriously difficult. Either you need multiple heads ready to go during the print which increases operating and maintenance costs for your printer, or you need to stop the print to switch the filament and then hope that everything matches up when the print is resumed. There are some workarounds to this problem, but not many of them are as smooth an effortless as this one which uses erasable pen ink to add colors to the filament on the fly.

Erasable pen ink is a thermochromic material that doesn’t get removed from paper when erased like graphite from a pencil. Instead the heat from the friction of erasing causes it to become transparent. By using this property for a 3D print, the colors in the print can be manipulated simply by changing the temperature of the hot end. Of course the team at [Autodrop3d] had quite a learning curve when experimenting with this method, as they had to run the extruder at a much lower temperature than normal to have control over the ink’s color, had to run the print much slower than normal, and were using a very sticky low-temperature plastic for the print.

With all of these modifications to the print setup, there are bound to be some limitations in material and speed, but the results of the project speak for themselves. This allows for stock 3D printers to use this method with no hardware modifications, and the color changes can be done entirely in software. While everyone catches up with this new technology, there are some other benefits to a 3D printer with multiple print heads, though, and some clever ways of doing the switching without too much interruption.

Continue reading “Erasable Pen Ink Adds Colors To 3D Prints” →

FPGA Retrocomputer: Return To Moncky

September 26, 2021 by 5 Comments

Part of the reason that retrocomputers are still so popular despite their obsolescence is that it’s possible to understand the entire inner workings of a computer like this, from the transistors all the way up to the software. Comparatively, it will likely be a long time (if ever) before anyone is building a modern computer from discrete components. To illustrate this point, plenty of 8-bit computers are available to either restore from original 80s hardware or to build from kits. And if you’d like to get even deeper into the weeds you can design your own computer including the instruction set completely from the ground up using an FPGA.

This project, called the Moncky project, is a step above the usual 8-bit computer builds as it is actually a 16-bit computer. It is built around an Arty Spartan-7 FPGA dev board running around 20 MHz and has access to 2 x 128 kB dual-port RAM for memory. To access the outside world there is a VGA output, PS/2 capability, SPI, and uses an SD card as a hard drive. This project really shines in the software, though, as the project creator [Kris Demuynck] builds everything from scratch in order to illustrate how everything works for educational purposes, and is currently working on implementing a C compiler to make programming the computer easier.

All of the project files, as well as all of the code, are available on the project’s GitHub page if you’d like to follow along or build on this homebrew 16-bit computer. It’s actually the third iteration of this computer, with the Moncky-1 and Moncky-2 being used to develop the more basic building blocks for this computer. While it’s not the first 16-bit computer we’ve seen implemented on an FPGA, it is one of the few that builds its own RISC instruction set and associated software rather than cloning a known existing processor. We’ve also seen some interesting x86 implementations on an FPGA as well.

Thanks to [koen-ieee] for the tip!

Fight Disease With A Raspberry Pi

September 20, 2021 by 4 Comments

Despite the best efforts of scientists around the world, the current global pandemic continues onward. But even if you aren’t working on a new vaccine or trying to curb the virus with some other seemingly miraculous technology, there are a few other ways to help prevent the spread of the virus. By now we all know of ways to do that physically, but now thanks to [James Devine] and a team at CERN we can also model virus exposure directly on our own self-hosted Raspberry Pis.

The program, called the Covid-19 Airborne Risk Assessment (CARA), is able to take in a number of metrics about the size and shape of an area, the number of countermeasures already in place, and plenty of other information in order to provide a computer-generated model of the number of virus particles predicted as a function of time. It can run on a number of different Pi hardware although [James] recommends using the Pi 4 as the model does take up a significant amount of computer resources. Of course, this only generates statistical likelihoods of virus transmission but it does help get a more accurate understanding of specific situations.

For more information on how all of this works, the group at CERN also released a paper about their model. One of the goals of this project is that it is freely available and runs on relatively inexpensive hardware, so hopefully plenty of people around the world are able to easily run it to further develop understanding of how the virus spreads. For other ways of using your own computing power to help fight Covid, don’t forget about Folding@Home for using up all those extra CPU and GPU cycles.

Tracking Maximum Power Point For Solar Efficiency

September 19, 2021 by 44 Comments

In days of yore when solar panels weren’t dirt cheap, many people (and even large energy companies) used solar trackers to ensure their panels were always physically pointed at the sun to make sure they harvested every watt of energy possible. Since the price of panels has plummeted, though, it’s not economical to install complex machines to track the sun anymore. But all solar farms still track something else, called the Maximum Power Point (MPP), which ensures that even stationary panels are optimized for power production.

While small MPP trackers (MPPT) are available in solar charge controllers in the $200 range that are quite capable for small off-grid setups, [ASCAS] aka [TechBuilder] decided to roll out an open source version with a much lower price tag since most of the costs of these units are in R&D rather than in the actual components themselves. To that end, the methods that he uses for his MPPT are essentially the same as any commercial unit, known as synchronous buck conversion. This uses a specially configured switch-mode power supply (SMPS) in order to match the power output of the panels to the best power point for any given set of conditions extremely rapidly. It even works on many different battery configurations and chemistries, all configurable in software.

This build is incredibly extensive and goes deep into electrical theory and design choices. One design choice of note is the use of an ESP32 over an Arduino due to the higher resolution available when doing analog to digital conversion. There’s even a lengthy lecture on inductor core designs, and of course everything on this project is open source. We have also seen the ESP32 put to work with MPPT before, although in a slightly less refined but still intriguing way.

Thanks to [Sofia] for the tip!

Continue reading “Tracking Maximum Power Point For Solar Efficiency” →

Useless Machine Is A Clock

September 14, 2021 by 15 Comments

Useless machines are a fun class of devices which typically turn themselves off once they are switched on, hence their name. Even though there’s no real point, they’re fun to build and to operate nonetheless. [Burke] has followed this idea in spirit by putting an old clock he had to use with his take on a useless machine of sorts. But instead of simply powering itself off when turned on, this useless machine dislodges itself from its wall mount and falls to the ground anytime anyone looks at it.

It’s difficult to tell if this clock was originally broken when he started this project, or if many rounds of checking the time have caused the clock to damage itself, but either way this project is an instant classic. Powered by a small battery driving a Raspberry Pi, the single-board computer runs OpenCV and is programmed to recognize any face pointed in its general direction. When it does, it activates a small servo which knocks it off of its wall, rendering it unarguably useless.

[Burke] doesn’t really know why he had this idea, but it’s goofy and fun. The duct tape that holds everything together is the ultimate finishing touch as well, and we can’t really justify spending too much on fit and finish for a project that tosses itself around one’s room. On the other hand, if you’re looking for a more refined useless machine, we have seen some that have an impressive level of intricacy.

Thanks to [alchemyx] for the tip!

Continue reading “Useless Machine Is A Clock” →

Small low-cost CNC mill with rotary tool

Minimal Mill: The Minamil

September 10, 2021 by 35 Comments

Having a few machine tools at one’s disposal is a luxury that not many of us are afforded, and often an expensive one at that. It is something that a large percentage of us may dream about, though, and with some commonly available tools and inexpensive electronics a few people have put together some very inexpensive CNC machines. The latest is the Minamil, which uses a rotary tool and straps it to an economical frame in order to get a functional CNC mill setup working.

This project boasts impressively low costs at around $15 per axis. Each axis uses readily available parts such as bearings and threaded rods that are readily installed in the mill, and for a cutting head the build is based on a Dremel-like rotary tool that has a similarly low price tag. Let’s not ignore the essentially free counterweight that is used.

For control, an Arduino with a CNC shield powers the three-axis device which is likely the bulk of the cost of this project. [Paul McClay] also points out that a lot of the material he needed for this build can be salvaged from things like old printers, so the $45 price tag is a ceiling, not a floor.

The Minamil has been demonstrated milling a wide variety of materials with excellent precision. Both acrylic and aluminum are able to be worked with this machine, but [Paul] also demonstrates it in its capacity to mill PCBs. It does have some limitations but for the price it seems that this mill can’t be beat, even compared to his previous CNC build which repurposed old CD drives.

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