Alice Evans: Brucellosis, or Why We Pasteurize Milk

It’s easy to forget how much illness and death was caused by our food and drink just one hundred years ago. Our modern food systems, backed by sound research and decent regulation, have elevated food safety to the point where outbreaks of illness are big news. If you get sick from a burger, or a nice tall glass of milk, it’s no longer a mystery what happened. Instead we ask why, and “who screwed up?”

In the early 20th century though, many food-borne illnesses were still a mystery, and microbiology was a scientific endeavor that was just getting started. Alice Catherine Evans was an unlikely figure to make a dent in this world at the time, but through her research at the United States Department of Agriculture’s (USDA), and later at the Hygienic Laboratory (now the National Institute of Health) she had a huge impact on the field of bacteriology, the dairy industry, and consumer safety. Continue reading “Alice Evans: Brucellosis, or Why We Pasteurize Milk”

Low-energy ESP8266-based Board Sleeps Like a Log Until Triggered

Given the popularity of hacking and repurposing Amazon Dash buttons, there appears to be a real need amongst tinkerers for a simple “do something interesting on the internet when a button is pressed” device. If you have this need but don’t feel like fighting to bend a Dash device to your will, take a look at [Kevin Darrah]’s trigBoard instead.

The trigBoard is a battery-powered, ESP8266-based board that includes some clever circuitry to help it barely sip power (less than one microamp!) while waiting to be triggered by a digital input. This input could be a magnetic reed switch, push button, or similar, and you can configure the board for either normally open or normally closed switches.

The clever hardware bits that allow for such low power consumption are explained in [Kevin]’s YouTube video, which we’ve also embedded after the break. To summarize: the EPS8266 spends most of it’s time completely unpowered. A Texas Instruments TPL5111 power timer chip burns 35 nanoamps and wakes the ESP8266 up every hour to check on the battery. This chip also has a manual wake pin, and it’s this pin – along with more power-saving circuitry – that’s used to trigger actions based on the external input.

Apparently the microcontroller can somehow distinguish between being woken up for a battery check versus a button press, so you needn’t worry about accidentally sending yourself an alert every hour. The default firmware is set up to use Pushbullet to send notifications, but of course you could do anything an EPS8266 is capable of. The code is available on the project’s wiki page.

The board also includes a standard micro-JST connector for a LiPo battery, and can charge said battery through a micro-USB port. The trigBoard’s full schematic is on the wiki, and pre-built devices are available on Tindie.

[Kevin]’s hardware walkthrough video is embedded after the break.

Continue reading “Low-energy ESP8266-based Board Sleeps Like a Log Until Triggered”

Pint-sized Jacob’s Ladder Packs 10,000 Volts in a Pickle Jar

File this one away for your mad scientist costume next Halloween: [bitluni]’s Pocket Jacob’s Ladder is the perfect high voltage accessory for those folks with five dollars in parts, a 3D printer, and very big pockets.

[bitluni]’s video shows you all the parts you’ll need and guides you through the very simple build process. For parts, you’ll require a cheap and readily-available high-voltage transformer, a battery holder, some silver wire for the conductors, and a few other minor bits like solder and a power switch.

Once the electronics are soldered together, they’re stuffed inside a 3d printed case that [bitluni] designed with FreeCAD. The FreeCAD and STL files are all available on Thingiverse. We’re not sure what type of jar [bitluni] used to enclose the electrodes. If your jar isn’t a match, you’ll have to get familiar with FreeCAD or start from scratch with your favorite CAD package.

Either way, we enjoy the slight nod toward electrical safety and the reuse of household objects for project enclosures.

If you’re interested in a Jacob’s Ladder with significantly higher voltage we’ve got you covered, or we’ve also written about another tiny portable Jacob’s Ladder.

The full video is embedded after the break.

Continue reading “Pint-sized Jacob’s Ladder Packs 10,000 Volts in a Pickle Jar”

Short Length of Wire Turns STM32 Microcontroller into Good-enough Wireless UART Blaster

Hackaday regular [befinitiv] wrote into the tip line to let us know about a hack you might enjoy, wireless UART output from a bare STM32 microcontroller. Desiring the full printf debugging experience, but constrained both by available space and expense, [befinitiv] was inspired to improvise by a similar hack that used the STM32 to send Morse code over standard FM frequencies.

In this case, [befinitiv]’s solution is both more useful and slightly more legal, as the software uses the 27 MHz ISM band to blast out ASK modulated serial data through a simple wire antenna attached to one of the microcontroller’s pins. The broadcast can then be picked up by an RTL-SDR receiver and interpreted back into a stream of data by GNU Radio.

The software for the STM32 and the GNU Radio Companion graph are both available on Bitbucket. The blog post goes into some detail explaining how the transmitter works and what all the GNU Radio components are doing to claw the serial data back from the ether.

[cover image cc by-sa licensed by Adam Greig, randomskk on Flickr]

Open Data Cam Combines Camera, GPU, and Neural Network in an Artisanal DIY Cereal Box

The engineers and product designers at [moovel lab] have created the Open Data Cam – an AI camera platform that can identify and count objects as they move through its field of view – along with an open source guide for making your own.

Step one: get out your ruler and utility knife. In this world of ubiquitous 3D-printers they’ve taken a decidedly low-tech approach to the project’s enclosure: a cut, folded, and zip-tied plastic box, with a cardboard frame inside to hold the electronic bits. It’s “splash proof” and certainly cheap to make, but we’re a little worried about cooling and physical protection for the electronics inside, as they’re not exactly cheap and rugged components.

So what’s inside? An Nvidia Jetson TX2 board, a LiPo battery with some charging circuitry, and a standard webcam. The special sauce, however, is the software, which is available on GitHub. [Moovel lab]’s engineers have put together a nice-looking wifi-accessible mobile UI for marking the areas where you’d like the software to identify and tally objects. The actual object detection and identification tasks are performed by the speedy YOLO neural network, a task the Nvidia board’s GPU is of course well suited for.

As the Open Data Cam’s unblinking glass eye gazes upon our urban environments, it will log its observations in an ancient and mysterious language: CSV. It’s up to you, human, to interpret this information and use it for good.

A summary video and build time lapse are embedded after the break.

Continue reading “Open Data Cam Combines Camera, GPU, and Neural Network in an Artisanal DIY Cereal Box”

Blazing Fast Raspberry Pi Display Driver Will Melt Your Face then Teach You How

Reader [poipoi] recently wrote into our tip line to tell us about an “amazingly fast” Raspberry Pi display driver with a README file that “is an actual joy to read”. Of course, we had to see for ourselves. The fbcp-ili9341 repo, by [juj], seems to live up to the hype! The software itself appears impressive, and the README is detailed, well-structured, educational, and dare we say entertaining?

The driver’s main goal is to produce high frame rates — up to around 60 frames per second — over an SPI bus, and it runs on various Raspberry Pi devices including the 2, 3 and Zero W. Any video output that goes to the Pi’s HDMI port will be mirrored to a TFT display over the SPI bus. It works with many of the popular displays currently out there, including those that use the ILI9341, ILI9340, and HX8357D chipsets.

The techniques that let [juj] coax such frame rates out of a not-terribly-fast serial bus are explained in detail in the README’s How it Works section, but much of it boils down to the fact that it’s only sending changed pixels for each frame, instead of the full screen. This cuts out the transmission of about 50% of the pixels in each update when you’re playing a game like Quake, claims the author. There are other interesting performance tweaks as well, so be sure to check out the repo for all the details.

There’s a video comparing the performance of fbcp-ili9341 to mainline SPI drivers after the break.

Continue reading “Blazing Fast Raspberry Pi Display Driver Will Melt Your Face then Teach You How”

Use Nodes to Code Loads of G-code for 3D CNC Carving

Most CNC workflows start with a 3D model, which is then passed to CAM software to be converted into the G-code language that CNC machines love and understand. G-code, however, is simple enough that rudimentary coding skills are all you need to start writing your very own programmatic CNC tool paths. Any language that can output plain text is fully capable of enabling you to directly control powerful motors and rapidly spinning blades.

[siemenc] shows us how to use Grasshopper – a visual node-based programming system for Rhino 3D – to output G-code that makes some interesting patterns and shapes in wood when fed to a ShopBot. Though the Rhino software is a bit expensive and thus is not too widely available, [siemenc] walks through some background, theory, and procedures that could be useful and inspirational no matter what software or programming language you’re using to create your bespoke G-code.

For links to code and related blog posts, plus more lovely pictures of intricately carved plywood, check out [siemenc]’s personal site as well.

[via Bantam Tools]