USB Arduino Into AVR TPI Programmer

January 6, 2017 by Elliot Williams 4 Comments

Turning an Arduino of virtually any sort into a simple AVR 6-pin ISP programmer is old hat. But when Atmel came out with a series of really tiny AVR chips, the ATtiny10 and friends with only six pins total, they needed a new programming standard. Enter TPI (tiny programming interface), and exit all of your previously useful DIY AVR programmers.

[Kimio Kosaka] wrote a dual-purpose TPI and ISP firmware for the ATmegaxxUn chips that are used as a USB-serial bridge on the Unos, and constitute the only chip on board a Leonardo or Micro. The catch? You’re going to have to do a little bit of fine-pitch soldering. Specifically, [Kosaka-san] wants you to get access to an otherwise obscured signal by drilling out a via. We’d do it just for that alone.

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Toshiro Kodera: Electromagnetic Gyrotropes

January 4, 2017 by Elliot Williams 12 Comments

We’ve learned a lot by watching the talks from the Hackaday Superconferences. Still, it’s a rare occurrence to learn something totally new. Microwave engineer, professor, and mad hacker [Toshiro Kodera] gave a talk on some current research that he’s doing: replacing natural magnetic gyrotropic material with engineered metamaterials in order to make two-way beam steering antennas and more.

If you already fully understood that last sentence, you may not learn as much from [Toshiro]’s talk as we did. If you’re at all interested in strange radio-frequency phenomena, neat material properties, or are just curious, don your physics wizard’s hat and watch his presentation. Just below the video, we’ll attempt to give you the Cliff’s Notes.

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Rust Running On The Realtek RTL8710: ESP8266 Alternative?

January 4, 2017 by Elliot Williams 26 Comments

For simply getting your project connected to WiFi, a least among hacker circles, nothing beats the ESP8266. But it’s not the only player out there, and we love to see diversity in the parts and languages that we use. One of the big shortcomings of the ESP8266 is the slightly-oddball Xtensa CPU. It’s just not as widely supported by various toolchains as its ARM-based brethren.

And so, when [Zach] wanted to do some embedded work in Rust, the ESP8266 was out of the picture. He turned to the RTL8710, a very similar WiFi module made by Realtek. Documentation for the RTL8710 is, at the moment, crappy, much as the ESP8266 documentation was before the hacker community had at it. But in trade for this shortcoming, [Zach] got to use the LLVM compiler, which supports the ARM architecture, and that means he can code in Rust.

In the end, the setup that [Zach] describes is a mix of FreeRTOS and some of the mbed libraries, which should be more than enough to get you up and running fairly painlessly on the chip. We’ve actually ordered a couple of these modules ourselves, and were looking to get started in straight C, but having Rust examples working doesn’t hurt, and doesn’t look all that different.

Is anyone else using the RTL8710? An ARM-based, cheap WiFi chip should be interesting.

Derek Schulte: Path Planning For 3D Printers

January 3, 2017 by Elliot Williams 54 Comments

[Derek Schulte] designed and sells a consumer 3D printer, and that gives him a lot of insight into what makes them tick. His printer, the New Matter MOD-t, is different from the 3D printer that you’re using now in a few different ways. Most interestingly, it uses closed-loop feedback and DC motors instead of steppers, and it uses a fairly beefy 32-bit ARM processor instead of the glorified Arduino Uno that’s running many printers out there.

The first of these choices meant that [Derek] had to write his own motor control and path planning software, and the second means that he has the processing to back it up. In his talk, he goes into real detail about how they ended up with the path planning system they did, and exactly how it works. If you’ve ever thought hard about how a physical printhead, with momentum, makes the infinitely sharp corners that it’s being told to in the G-code, this talk is for you. (Spoiler: it doesn’t break the laws of physics, and navigating through the curve involves math.)

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Humidity Sensor Shootout

January 3, 2017 by Elliot Williams 39 Comments

If you want to measure humidity (and temperature, and maybe even barometric pressure) in a device that you’re building, have a look at this comprehensive test of seven different options. We’re going to summarize the results here, but you’ll really want to read up on the testing methodology — it’s great science hacking. Did you know about using saturated salt solutions to produce constant humidity levels for calibration? We didn’t.

The eBay hacker favorite, the so-called DHT22 module, doesn’t fare all that well, with one of six that [Robert] tested being basically horrible, and three of them breaking within two years of use. The one that works well, however, is pretty good. Feeling lucky?

The Bosch BME280 looks great. It costs a bit more as a bare part, and a few times more than that when it is mounted on a friendly module, but it seems to be very reliable. And you get a barometer thrown in for the extra work. Indeed, it performed so well that Hackaday contributor [Nava Whiteford] put the part under a scanning electron microscope to figure out what’s going on.

The other sensors were fine, with the HTU21D and SHT71 being standouts for their ultra-fast response. For the full details, go click on that link at the top. Having just installed a sextet of DHT22s in our house last year, we’re left with that sinking feeling that we may have gotten what we paid for, which wasn’t much. At least they’re all still running.

Thanks to [Dodutils] and [mac012345] via comments in another thread.

OWL Insecure Internet Of Energy Monitors

January 2, 2017 by Elliot Williams 25 Comments

[Chet] bought an electricity monitor from OWL, specifically because it was open and easy to hack on at him within the confines of his home network. Yay! Unfortunately, it also appears to be easy to ~~hack~~ read outside of his home network too, due to what appears to be extraordinarily sloppy security practices.

The short version of the security vulnerability is that the OWL energy monitors seem to be sending out their data to servers at OWL, and this data is then accessible over plain HTTP (not HTTPS) and with the following API: http://beta.owlintuition.com/api/electricity/history_overview.php?user=&nowl=&clientdate=. Not so bad, right? They are requiring username and password, plus the ID number of the device. Maybe someone could intercept your request and read your meter remotely, because it’s not encrypting the transaction?

Nope. Much worse. [Chet] discovered that the username and password fields appear not to be checked, and the ID number is the device’s MAC address which makes is very easy to guess at other device IDs. [Chet] tried 256 MACs out, and got 122 responses with valid data. Oh my!

Take this as a friendly reminder and a cautionary tale. If you’re running any IoT devices, it’s probably worth listening to what they’re saying and noting to whom they’re saying it, because every time you send your data off to “the cloud” you’re trusting someone else to have done their homework. It is not a given that they will have.

Tiny Game Of Simon On An ATtiny13

December 31, 2016 by Elliot Williams 13 Comments

How much game can you get out of a chip with only 1 kB of flash memory and (five or) six free GPIOs? Well, you can get it to play the classic memory game, Simon. [Vojtak] is submitting this project for the 1 kB Challenge, but it looks like it’s already been used to teach simple microcontrollering to teenagers as well, so the code is actually straightforward to read, but full of nice features.

Neat tricks include sharing button-press sensing and LED driving on the same pin, which was necessary to make everything work on such a small chip. A simple linear-congruential pseudorandom sequence provides the variation, and it’s seeded by slow-clock/fast-clock timing jitter, so you’re probably not going to see the same sequence twice. (It’s not the best random number generator ever, but it’ll do.) If that weren’t enough, high scores (and the random seed for the game) are saved to EEPROM so that you can brag to your friends or re-live your previous moments of glory.

The board is easily solderable together as well. This is a fantastic beginner project, with details in the code that everyone can learn from. It’s a great game, and a great demonstration of what you can do with a dollar’s worth of parts and 1 kB of code.

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