Making Software Defined Radio Portable

While most smartphones can receive at least some radio, transmitting radio signals is an entirely different matter. But, if you have an Android phone and a few antennas (and a ham radio license) it turns out that it is possible to get a respectable software-defined radio on your handset.

[Adrian] set this up to be fully portable as well, so he is running both the transceiver and the Android phone from a rechargeable battery bank. The transceiver is also an interesting miniaturized version of the LimeSDR, the Lime SDR Mini, a crowdfunded Open Source radio platform intended for applications where space is at a premium. It operates on the 10 MHz to 3.5 GHz bands, has two channels, and has a decent price tag too at under $100.

For someone looking for an SDR project or who needs something very portable and self-contained, this could be a great option. The code, firmware, and board layout files are all also open source, which is always a great feature. If you’re new to SDR though, there’s a classic project that will get you off the ground for even less effort.

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Hackaday Links: October 22, 2017

A few weeks ago, the popcorn overflowed because of an ambiguous tweet from AdafruitDid Adafruit just buy Radio Shack? While everyone else was foaming at the mouth, we called it unlikely. The smart money is that Adafruit just bought a few fancy stock certificates, incorporation papers, and other official-looking documents at the Radio Shack corporate auction a few months ago. They also didn’t pick up that monster cache of Trash-80s, but I digress.

Here’s some more popcorn: Adafruit just applied for the ‘Radiofruit’ trademark. Is this Adafruit’s play to take over the Radio Shack brand? Probably not; they put a bunch of radio modules on Feather boards, and are just doing what they do. It does demonstrate Adafruit’s masterful manipulation effective use of social media, though.

Remember those 2D tilty maze rolling marble labyrinth game things? Here’s a 3D version on Kickstarter. It’s handheld, so this really needs a gimbal and associated twisty knobs.

In a video making the meme rounds, someone found an easter egg in the gauge cluster of a Russian GAZ van. It plays Tetris.

It’s Sunday, so it’s time to talk Star Trek. Here’s something interesting that hit my email: a press release telling me, “Trekkies Scramble To Get The First Toothbrush In Space As Seen On Star Trek Discovery”. This is the toothbrush, and here is the press kit. Dumb? Not at all. Star Trek has a long history of using off-the-shelf tools and devices for props. For example, the hyperspanners seen in Star Trek: Enterprise were actually this non-contact thermometer available from Harbor Freight. At least the hyperspanners and thermometers came out of the same injection mold.

There’s a new LimeSDR board on CrowdSupply. It extends any LimeSDR to 10 GHz.

Kerf bending is the application of (usually laser-cut) slots to bend plywood around corners. You’ve seen it a million times before, and done correctly the technique can produce some very interesting results. What about metal, though? You need a pretty big laser for that. [Proto G] is using a 2000 W fiber laser to experiment with kerf bending in stainless steel. It works as you would expect, and we eagerly await someone to replicate this, if only to see another 2000 Watt laser in action.

Cheap, Full-Duplex Software Defined Radio With The LimeSDR

A few years ago, we saw the rise of software-defined radios with the HackRF One and the extraordinarily popular RTL-SDR USB TV tuner dongle. It’s been a few years, and technology is on a never-ending upwards crawl to smaller, cheaper, and more powerful widgets. Now, some of that innovation is making it to the world of software-defined radio. The LimeSDR Mini is out, and it’s the cheapest and most capable software defined radio yet. It’s available through a Crowd Supply campaign, with units shipping around the beginning of next year.

The specs for the LimeSDR mini are quite good, even when compared to kilobuck units from Ettus Research. The frequency range for the LimeSDR Mini is 10 MHz – 3.5 GHz, bandwidth is 30.72 MHz, with a 12-bit sample depth and 30.72 MSPS sample rate. The interface is USB 3.0 (the connector is male, and soldered to the board, but USB extension cables exist), and the LimeSDR is full duplex. That last bit is huge — the RTL-SDR can’t transmit at all, and even the HackRF is only half duplex. This enormous capability is thanks to the field programmable RF transceiver found in all of the LimeSDR boards. We first saw these a year or so ago, and now these boards are heading into the hands of hackers. Someone’s even building a femtocell out of a Lime board.

The major selling point for the LimeSDR is, of course, the price. The ‘early bird’ rewards for the Crowd Supply campaign disappeared quickly at $99, but there are still plenty available at $139. This is very inexpensive and very fun — on the Crowd Supply page, you can see a demo of a LimeSDR mini set up as an LTE base station, streaming video between two mobile phones. These are the golden days of hobbyist SDR.

Hackaday Links: June 19, 2016

Wait a minute. We’re almost through June and we haven’t seen anyone’s ‘DIY air conditioning’ setup. Oh the shame! How could we ever argue about thermodynamics otherwise? Here’s some copper tubing wrapped around a fan. Does it make sense? Assuming you’re making the ice (or cold whatever) in a room separated from the crappy air con, and you don’t have to pay for electricity (or ice), and you don’t mind hauling buckets of ice every few hours, yes. It’ll work. Now we can argue if you should put salt in the ice water…

I know I mentioned this in last week’s links post, but [Arsenijs]’s Raspberry Pi project is growing by leaps and bounds. He already has more than 33 followers to this project (awesome!) and 3.3k views on his project page. Not only is it climbing in popularity, but this is also a great use for the Raspberry Pi. You don’t see projects like this come around very often.

The Goliath is a quadcopter powered by a lawnmower engine. It was an entry in the first Hackaday Prize, but the project literally never got off the ground. There’s now a Mk. II version in the works. Goliath is getting a new frame made out of aluminum tube and rivets. There’s going to be ducts on the props, and this version might actually fly.

You did know Hackaday has it’s own Hackaspace, right? Technically it’s the Supplyframe Design Lab, but there are still a few skull ‘n wrenches hidden in the rafters. The Design Lab is hosting an open house this week on June 23rd, and the design lab residencies will begin July 1st. If you have an idea for something you’d like to build, here’s the residency application.

The LimeSDR is a powerful next generation software defined radio that’s currently on CrowdSupply The crowdfunding campaign ends in just a few days. It’s a very impressive tool, able to send and receive anything from 100 kHz to 3.8 GHz.

Last week one of our writers posted a review on the Monoprice MP Select Mini 3D printer. This printer is becoming stupidly popular, and Monoprice has depleted their inventory twice since then. I’ve been watching the product page for this printer for a while now, and here’s what happens: 1) Printer is out of stock, with an ETA of about a month in the future. 2) Printer is still out of stock, ETA is a few days away. 3) Monoprice has this printer in stock. This cycle seems to repeat every week or so.

Arduino Raycasting. When you think of raycasting, you probably think about Wolfenstein 3D, or other barely 3D games. You don’t need a powerful CPU like a 386 for raycasting – you can do it on an Arduino. The display is a 32×16 matrix of LEDs, control is through a Wii Nunchuck, and yes, head-bobbing is implemented. Here’s a video.

Hackaday Links: May 15, 2016

The Hackaday Overlords (or Hackaday family) are running a series of AMAs on SupplyFX. What is SupplyFX? It’s a social network for EEs. Who’s in the first AMA? [Brady Forrest], the guy who runs Highway1, a Bay Area hardware accelerator. They’re the accelerator responsible for the lustworthy Keyboardio, and the startup that is purely mechanical and has shipped zero lines of code, CoolChip. If you want to talk about hardware startups, [Brady] is your man. The AMA is tomorrow, May 16th, at 13:00 Pacific.

Makerbot is dead, or at least they will be soon. Whatever. Nothing of value was lost. Lulzbot, on the other hand, is going gangbusters. They saw eight hundred percent growth over the last two years. and $15M in revenue in 2015. They did this all with open source hardware and software, and using 3D printing in a manufacturing context. They’re the jewel of the Open Hardware movement, and a shining example of what Free Software can do.

The current generation of software defined radios started with the ubiquitous TV tuner dongles, and quickly graduated to the HackRF. You can only get so much bandwidth out of a USB 2.0 socket, and the newest and bestest SDR is the LimeSDR. They’re about halfway through their crowdfunding campaign (and halfway funded), and have finally changed out the USB A connector to a USB micro B connector. Good choice.

The ESP8266 is quickly becoming the go-to device for when you want a cheap way to put a sensor on the Internet. The only problem is programming it. No problem – here’s a bunch of Lua scripts that do 90% of everything. Need to read a PIR sensor? Light up a few LEDs? Put the data from a temperature and humidity on the Internet? There you have it.

The Vintage Computer Festival West is back on this year. We’ve gone to VCF East in New Jersey for a few years now, and had a few occasional outings to the southeast and midwest Vintage Computer Festivals over the years. This is the first time the west coast has had a Vintage Computer Festival in several years. It’s in Mountain View, on August 6th and 7th. Yes, that’s the same weekend as DEF CON.

E3D, makers of fine hot ends and 3D printer paraphernalia, have released a new kind of filament. It’s called Edge, it’s based on PET, and it prints as easily as PLA, with better mechanical properties than ABS. A few sample prints made from Edge were at this year’s Midwest RepRap Festival, and the Edge’s bridging ability is crazy. You need a heated bed for Edge and it’s sensitive to moisture, but it has some very interesting properties that can be cleverly exploited.

In other filament news, Colorfabb released a filament to print clear parts. Yes, that’s very weird. Clear parts require 100% infill, meaning it will use a lot of filament. It’s still very advanced wizardry, and I’m very interested in seeing the first print of a sanded and polished convex lens.

Holy Crap it’s the 3D printing edition of the links post. [Prusa] just released the latest version of the i3. It’s now bigger: 250x210x200mm build volume. The heated bed – [Prusa] was one of the first to experiment with PCB heated beds – is now vastly improved when looking at it through a FLIR. The Mk. 42 heated bed doesn’t have a hot center or cool corners. PEI sheet removes the need for blue painters tape, glass, aqua net, or glue sticks. The printer has self-test capabilities. The mechanics of the printer, especially the Z axis, are improved. [Prusa] will be selling this as a kit for ~19000 Czech Crowns or $699 USD, but he’s RepRap to the core. Buy a spool and start printing your next printer.