Extremely Detailed FMCW Radar Build

A lot of hackers take the “learn by doing” approach: take something apart, figure out how it works, and re-purpose all of the parts. [Henrik], however, has taken the opposite approach. After “some” RF design courses, he decided that he had learned enough to build his own frequency-modulated continuous wave radar system. From the level of detail on this project, we’d say that he’s learned an incredible amount.

[Henrik] was looking to keep costs down and chose to run his radar in the 6 GHz neighborhood. This puts it right in a frequency spectrum (at least in his area) where radar and WiFi overlap each other. This means cheap and readily available parts (antennas etc) and a legal spectrum in which to operate them. His design also includes frequency modulation, which means that it will be able to determine an object’s distance as well as its speed.

There are many other design considerations for a radar system that don’t enter into a normal project. For example, the PCB must have precisely controlled trace widths so that the impedance will exactly match the design. In a DC or low-frequency AC system this isn’t as important as it is in a high-frequency system like this. There is a fascinating amount of information about this impressive project on [Henrik]’s project page if you’re looking to learn a little more about radio or radar.

Too daunting for you? Check out this post on how to take on your first radar project.

Kentucky-Fried Induction Furnace

[John] and [Matthew] built an induction-heater based furnace and used it to make tasty molten aluminum cupcakes in the kitchen. Why induction heating? Because it’s energy efficient and doesn’t make smoke like a fuel-based furnace. Why melt aluminum in the kitchen? We’re guessing they did it just because they could. And of course a video, below the break, documents their first pour.

Now don’t be mislead by the partly low-tech approach being taken here. Despite being cast in a large KFC bucket, the mini-foundry is well put together, and the writeup of exactly how it was built is appreciated. The DIY induction heater is also serious business, and it’s being monitored for temperature and airflow across the case’s heatsinks. This is a darn good thing, because the combination of high voltage and high heat demands a bit of respect.

Anyway, we spent quite a while digging through [John]’s website. There’s a lot of good information to be had if you’re interested in induction heaters. Nonetheless, we’ll be doing our metal casting in the back yard.

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Trinket Everyday Carry Contest Drawing #1 Results

We just had our first drawing for the Trinket Everyday Carry Contest. Thanks to a little help from random.org, the winner is [Korishev] with his project Trinket Timer!

korishev-trinket-timer[Korishev] finds that family life calls for a lot of timed events, from how long the kids spend on their homework to keeping the peace by sharing toys. The plan is to build at least a one timer for each child that they will be able to carry around and use as needed. We hope he gets them in on the build to help sow the seeds of hardware development at a young age.

trinket-prize-blink1As the winner of the first drawing [Korishev] will receive this beautiful BLINK(1) MK2 from The Hackaday Store. The USB dongle houses a programmable RGB LED. We wonder if this will also be applied as an additional timer for the household?

If you didn’t win this week, don’t worry, there are still four more chances to win a random drawing! Our next drawing will be on 12/9/2014 at 9pm EST with the Cordwood Puzzle as a prize. To be eligible you need to submit your project as an official entry and publish at least one project log during the week.

The deadline for the main contest is January 2, 2014! There are just over 40 entries right now, and the top 50 will receive custom t-shirts. Of course the three top prizes are the real juicy ones. Let’s get those pocketable projects going!

A Wooden LED Matrix Coffee Table

[johannes] writes in with a pretty impressive LED table he built. The table is based around WS2801 serially addressable LEDs which are controlled by a Raspberry Pi. The Pi serves up a node.js-driven web interface developed by [Andrew Munsell] for a room lighting setup. The web interface controls the pattern shown on the display and the animation speed.

[johannes] built a wooden coffee table around the LED matrix, which includes a matte glass top to help diffuse the lighting. An outlet to plug in a laptop and two USB charging ports are panel-mounted on the side of the enclosure, which are a nice touch. The power supply for the LEDs is also inside the enclosure, eliminating the need for an external power brick.

While [johannes] hasn’t written any software of his own yet, he plans on adding music synchronization and visualizations for weather and other data. Check out the video after the break to see the table in action.

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Trinket Everyday Carry Contest Roundup: Sniffing Trinket And Portable Trollmaster 3000!

Hackaday’s  Trinket Everyday Carry Contest is heating up. In just one week we’ve already got over 30 entries! Many of the contenders are completely new open source projects based on the Pro Trinket. Our first drawing will be tonight, at 9pm EST. The first giveaway prize is a BLINK(1) MK2 from the Hackaday store. Make sure you have at least one project log and a photo up to be eligible for this week’s giveaway!

sniffingtrinketWe can’t help but mention how awesome some of the entries are.  [Georg Krocker] is taking on the problem of indoor air quality – not with a central sensor, but with a personal sensor that goes where you do. Sniffing Trinket is designed to monitor the air around the user. If the air quality drops, it will alert the user to open a window – or get the heck out. [Georg] has a few sensors in mind, but he’s starting with the MQ135 gas sensor and a DHT11 temperature/humidity sensor. If air quality starts to drop, 3 WS2812b LEDs will alert the user that there is a problem. The system can also be connected to a PC with USB for more accurate readings and logging.

[Georg] has an aggressive schedule planned, with a custom “Trinket Shield” PCB being laid out and ordered next week. January 2 is fast approaching, so hurry up and get those boards designed!

trololo[Dr Salica] is taking a more humorous approach to personal space. The Portable Trollmaster 3000 is designed to surround its wearer in a bubble of  “I Am Glad, ‘Cause I’m Finally Returning Back Home” aka “The Trololol song” as sung by Eduard Khil. [Dr Salica] plans to pair the Pro Trinket with the popular Sony MMR-70 FM transmitter. The Trinket is capable of playing back short audio clips, so with a bit of I2C magic, [Dr. Salica] will be able to hijack any nearby FM receiver, creating his own personal trollbox.

Do you have an idea for a great wearable or pocketable project? Check out the Trinket Everyday Carry Contest, and get hacking!

 

Retrotechtacular: Ma Bell’s Advanced Mobile Phone Service (AMPS)

This gem from the AT&T Archive does a good job of explaining the first-generation cellular technology that AT&T called Advanced Mobile Phone Service (AMPS). The hexagon-cellular network design was first conceived at Bell Labs in 1947. After a couple of decades spent pestering the FCC, AT&T was awarded the 850MHz band in the late 1970s. It was this decision coupled with the decades worth of Bell System technical improvements that gave cellular technology the bandwidth and power to really come into its own.

AT&T’s primary goals for the AMPS network were threefold: to provide more service to more people, to improve service quality, and to lower the cost to subscribers. Early mobile network design gave us the Mobile Service Area, or MSA. Each high-elevation transmitter could serve a 20-mile radius of subscribers, a range which constituted one MSA. In the mid-1940s, only 21 channels could be used in the 35MHz and 150MHz band allocations. The 450MHz band was introduced in 1952, provided another 12 channels.

repeated channelsThe FCC’s allocation opened a whopping 666 channels in the neighborhood of 850MHz. Bell Labs’ hexagonal innovation sub-divided the MSAs into cells, each with a radius of up to ten miles.

The film explains quite well that in this arrangement, each cell set of seven can utilize all 666 channels. Cells adjacent to each other in the set must use different channels, but any cell at least 100 miles away can use the same channels. Furthermore, cells can be subdivided or split. Duplicate frequencies are dealt with through the FM capture effect in which the weaker signal is suppressed.

Those Bell System technical improvements facilitated the electronic switching that takes place between the Mobile Telephone Switching Office (MTSO) and the POTS landline network. They also realized the automatic control features required of the AMPS project, such as vehicle location and automatic channel assignment. The film concludes its lecture with step-by-step explanations of inbound and outbound call setup where a mobile device is concerned.

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Arm Mounted Computer

Yet Another Awesome Working Prototype Of A PipBoy 3000

When we’re not busy writing up features on Hack a Day, some of the writers here have some pretty impressive projects on the go. One of our own, [Will Sweatman], just put the finishing touches on this amazing (and functional!) Pipboy 3000!

The funny thing is, [Will] here isn’t actually a very big gamer. In fact, he hasn’t even played Fallout. But when a friend queried his ability to build this so called “PipBoy 3000”, [Will] was intrigued.

His research lead him full circle, right back to here at Hack a Day. We’ve covered several PipBoy builds over the years, and [Will] fell in love with [Dragonator’s] 3D printed version — it was the perfect place to start. You see, [Dragonator] shared all the 3D models on his personal site!

Now this is where it starts to get cool. [Will] is using a 4D systems 4.3″ touch display, which doubles as the microprocessor — in fact, he didn’t even have to write a single line of code to program in it! The hardware can be programmed using the free Workshop 4 IDE, which allows him to use a visual editor to program the device. Watching a YouTube video on the Fallout 3 PipBoy, he was able to recreate all the menus with intricate detail to load onto the device. It even has GPIO which allow him to use buttons to navigate the menus (in addition to the touch screen stylus).

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