Technology, Rambling and Dragons
Dear gadget vendors: I like gadgets (at least good ones). I buy lots of them. I will probably continue to do so as disposable income allows. But I have a plea:
Please stop including a USB cable in the package with your products.
It’s unnecessary, it’s wasteful, it’s a giant hassle when the said cable is lousy (as it all too often is) and the cost of the “free” cable adds to the overall cost of your product.
I’ve got a Kenwood TM-D710A ham radio transceiver. This handy device is a portable 50W dual-band (2m and 70cm) radio, with a built-in packet radio TNC and some native APRS features. What it does not have (unlike the new TM-D710GA model) is a built-in GPS receiver.
This is a problem that can be fixed with a surprisingly small parts budget, provided you’re up for some fine-pitch soldering. Details after the break.
Here’s another update in my long-running digital compass project. It’s now sufficiently feature-complete to be a potentially useful end-user product. Major improvements including saving calibration data in EEPROM, improved display, error detection and temperature compensation.
Read on after the break.
I recently acquired a Spark Core, and (after some minor hassle) got it connected to my network and walked through the examples. Neat product, though to some extent it suffers from problems of “trying to make it easier for the noobs, with a failure mode of making it harder for everybody” and “everybody wants to write features, nobody wants to write documentation”.
Past the jump, I’ll explain how to get around the 32-character wireless passphrase limit, and how to use cloud compilation but with a real Makefile, local copies of your source code and your favorite text editor.
Finally, some progress on my AVR compass project. I’ve got a program that runs on the Adafruit Trinket and shows real compass headings, all in 3712 bytes. While it’s far from being a finished product, it’s a big step in the direction of one.
Below, I’ll give you the source code, talk about how recent compiler changes impact code size, tell you about a bug I fixed, and make a bunch of excuses for why this took so long.
This is another article in my series about developing a magnetometer-based digital compass. Last time, I talked about estimating code size, and what I might do to fit the application in the roughly 5.25K program space available on an Adafruit Trinket.
In this article, I replace the floating-point math with fixed-point, and make various space-saving improvements to the calibration and rotation code. Read on for more.
The Trinket microcontroller from Adafruit Industries is a tiny and inexpensive (US$8 for a single unit) way to control your electronics projects. One of the coolest things about it is that you can do I²C (and communicate to lots of inexpensive sensors and displays using only two pins) and still have plenty of room left over for your code in the ~5.5KB of flash on board.
Read on to see an example of how to do I²C communication on the Trinket (or anything with an Atmel ATTiny85) while shaving every possible byte. Also included: driving the Adafruit Mini 8×8 LED Matrix with I2C Backpack.
My command of Italian is pretty limited, but I’m pretty sure I’ve just been reading about a radio-controlled model aircraft named Mythical Beast which just won “Best of Show” at an exhibition in Toledo, Ohio. More details and video of a flight are available from the Hobby Media site. (Via BB.)
Update: Another video (somewhat better) is available on YouTube. English-language audio.
My love of gadgets is, I think, already well-established on these pages. I love food just as well, so it was probably inevitable that I’d decide to take some food and Do Science to It. And takes pictures of myself doing it. And put up a blog post about it.
Say you want a steak cooked perfectly, edge to edge. That means bringing the internal temperature of the entire thing to exactly the right point. It’s hard to do with a grill or a pan or a broiler, since those heat the outside more and the middle less, and you have to tightly control both time and temperature vs. the cut of meat.
The idea of sous-vide cooking is really simple: put the meat in an airtight, watertight vacuum bag. Plunge it into a water bath that’s exactly the temperature you want. Leave it there for a few hours — an hour plus or minus makes no difference. The devil, as usual, lies in the details — after the jump.
There are lots of proto boards for the AVR microcontroller, and lots of programmers. This post presents my approach, which features easy assembly, off-the-shelf PCB, extremely low parts cost and a built-in USB-based programmer. Circuit, PCB and firmware are all completely Open Source. Read on after the jump for details.