BrewBuddy is a Home Brewer’s Best Friend

Whether coffee, tea, or beer is your jam, brewing is a delicate pas de deux of time and temperature. Proper brewing of any of these beverages can elevate the experience from average to amazing. With this in mind, [Marcelo] created a time and temperature tool to dial in his beer-brewing process.

BrewBuddy is a complex application-specific timer with an integrated thermometer. It lets him program time and temperature profiles for both the mashing process and the boiling process and store up to 10 steps for each. BrewBuddy doesn’t control the brewing temperature, but it does unify temperature-taking and time-marking into one convenient device that can last about 20 hours on a single CR2032.

The system is based on an STM32 and an LMT86 analog temperature sensor which has been modified to sit inside a stainless steel tube. There are four directional buttons to navigate through intuitive menus to set the desired times and temperatures. As each step completes, the status LED lights up and BrewBuddy waits for confirmation via button push before moving on to the next step. If there’s a problem, the timer can be paused and resumed using the up/down buttons. [Marcelo] is working to perfect the case design, but he already has the board files and firmware up on GitHub. Open up a cold one and check out the demo videos after the break.

After boiling and cooling comes fermentation, and that requires careful monitoring of the sugar content. Here’s a tool for that.

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DS212 Oscilloscope Review: Open Source and Great for Hacking

We’ve seen plenty of oscilloscopes that look like repurposed cell phones. Usually, though, they only have one channel. The DS212, has two channels and a signal generator! [Marco] gives his review and a quick tear down in the video below.

The scope isn’t going to replace a big bench instrument, but for a portable scope with a rechargeable battery, it isn’t bad. The 1 MHz analog bandwidth combines with a 10 megasample per second front end and 8K of sample memory. The signal generator can produce basic waveforms up to 1 MHz. We were somewhat surprised the unit didn’t sport a touch screen, which is why you can see [Marco’s] fingers in the screenshot above. He seems to like the dual rotary encoder system the devices uses for navigation.

Where this really stands out is that it is open source for the the firmware running on the STM32 processor inside. We so rarely see this for commercially available bench tools and it makes this a fine hacking platform. It’s easy to imagine adding features like digital signals out and decoding digital data. It would be interesting to marry it with a WiFi chip and use it as a front end for another device over WiFi. Lots of possibilities. [Marco] shows that even though he’s not familiar with the STM32, he was able to add a custom waveform output to the device easily. This has the potential to be a custom troubleshooting platform for your builds. Lining up all of the sensing and signal generation settings for each specific type of test means you don’t need a guru to walk through the common failure modes of a product.

There are many small inexpensive scopes out there that might not match a big bench instrument but can still be plenty useful. [Jenny List] just reviewed one that comes in at around $21. And last year, we saw a sub-$100 scope that would net you just one channel scope. That’s progress!

An Awesome Open Mechanical Keyboard

Who doesn’t want a little added functionality to their  lives? Feeling a few shortcut keys would make working in Eagle a bit smoother, [dekuNukem] built his own programmable mechanical keypad: kbord.

It sports vibrant RGB LED backlight effects with different animations, 15 keys that execute scripts — anything from ctrl+c to backdoors — or simple keystrokes, up to 32 profiles, and a small OLED screen to keep track of which key does what!

kbord is using a STM32F072C8T6 microcontroller for its cost, speed, pins, and peripherals, Gateron RGB mechanical keys — but any clear key and keycaps with an opening for the kbord’s LEDs will do — on a light-diffusing switch plate, and SK6812 LEDs for a slick aesthetic.

Check out the timelapse video tour of his build process after the break! (Slightly NSFW, adolescent humor for a few seconds of the otherwise very cool video. Such is life.)

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Playing Mario on an Oscilliscope

Any display can be connected to a microcontroller and used as a display if you know the protocol to use and have enough power in your micro. Sometimes, an odd display is used just “because it’s there.” This seems to be the case for Reddit user [phckopper], who has used a STM32 and a PS2 joystick to play a version of a Mario game on an oscilloscope.

There’s not many technical details but [phckopper] lets us know that the rendering is done using the SPI on the STM, transferred via DMA, which is synchronized to two saw-tooth waves that are fed in to the X and Y axes of the oscilloscope.  The Z axis, which controls the brightness of the dot, is fed from the MOSI. By making the oscilloscope range all over the screen, similar to the way a CRT’s gun does, [] is able to draw sprites, rather than vector graphics. The display has a resolution of 400×400 and each sprite is 16×16. The input is from a PS2 joystick connected to [phckopper]’s PC, with the information communicated over UART using a simple protocol.

We don’t get to see much of the game in the video after the break, but it’s a pretty impressive job nonetheless, especially when you realize that [phckopper] did this project when he was just sixteen! There are a couple of other oscilloscope projects here at Hackaday, like this one, a great version of pong played on the ‘scope, or this one, showing off some great graphics.

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A Digital LCD Makeover For An Analogue CRT Spectrum Analyser

[Seb Holzapfel, VK2SEB] has a rather nice spectrum analyser, a Hewlett Packard 141T. It’s an entirely analogue instrument though, so it lacks some of the sophisticated features you might expect to see on its modern counterparts.

One feature the HP does have is a vertical deflection output that in effect allows the trace to be reproduced on an oscilloscope. [Seb] has taken that and applied it to an STM32F746 Discovery board with its associated LCD touchscreen to produce an interface for the HP that includes modern features such as trace normalisation and a waterfall view. Along the way he’s had to make a voltage level converter to render the HP’s scan output into a range acceptable for the ST board.

He goes into detail on his software for the project, which he is at pains to remind us is still very much a work in progress. He notes that the HP has a range of other outputs (on those “D” sockets that include co-axial connectors) that provide information about its band and scan settings, so there is ample possibility for further customisation.

If you are interested in this project then the code is all available via GitHub, otherwise you can watch his video below the break. He’s labelled it as “Part 1”, so we look forward to more on this project.

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Take the Blue Pill and Go Forth

Forth has a long history of being a popular hacker language. It is simple to bootstrap. It is expressive. It can be a very powerful system. [jephthal] took the excellent Mecrisp Forth and put it on the very inexpensive STM32 “blue pill” board to create a development system that cost about $2. You can see the video below.

If you have thirty minutes, you can see just how easy it is to duplicate his feat. The blue pill board has to be programmed once using an STM32 programmer. After that, you can use most standard Forth words and also use some that can manipulate the low-level microcontroller resources.

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STM32CubeMX Makes Makefiles

When hardware manufacturers make GUI code-generation tools, the resulting files often look like a canned-spaghetti truck overturned on the highway — there’s metaphorical overcooked noodles and red sauce all over the place. Sometimes we think they’re doing this willfully to tie you into their IDE. Not so the newest version of ST’s graphical STM32CubeMX, which guides you through a pleasant pin-allocation procedure and then dumps out, as of the latest version, a clean Makefile.

Yes, that’s right. This is a manufacturer software suite that outputs something you can actually use with whatever editor, GUI, compiler, or environment that you wish — even the command line. Before this release, you had to go through a hacky but functional script to get a Makefile out of the CubeMX. Now there’s official support for real hackers. Thanks, ST!

If you’re compiling on your own, you’ll need to update the BINPATH variable to point to your compiler. (We use the excellent GNU ARM Embedded Toolchain ourselves, which is super-easy to install on almost any Linux.) If you want to use STM32CubeMX with the Eclipse IDE, [kali prasad yadav] sent us PDF instructions — it’s not hard.

If you doubt that the availability of a free, open, and non-constraining toolchain can matter for a silicon vendor, we’d point to AVR and the Arduino platform that spun off of their support of GCC. Sure, Atmel still pushes their all-in-one wonder, Atmel Studio, which is better than the Arduino IDE by most any metric. But Studio is closed, and Arduino is open. We’d love to see the number of Studio users compared with Arduino users.

Congratulations to ST for taking a big step in the right, open-toolchain, direction.