HackRF, Or Playing From 30 MHz To 6 GHz

August 1, 2013 by Brian Benchoff 49 Comments

Up on Kickstarter, [Michael Ossmann] is launching the HackRF, an inordinately cheap, exceedingly capable software defined radio tool that’s small enough to lose in your laptop bag.

The HackRF was the subject of a lot of interest last time it was on Hackaday – the ability to receive up to 6GHz allows the HackRF to do a lot of very interesting things, including listening in on Bluetooth, WiFi, and 4G networks. Also, the ability to transmit on these frequencies means a lot of very interesting, and quite possibly slightly evil applications are open to anyone with a HackRF. Like the RTL-SDR dongles, the HackRF works with GNU Radio out of the box, meaning all those cool SDR hacks we’ve seen so far will work with this new, more powerful board.

Compared to the USB TV tuner cards that were so popular a year ago, the HackRF has 10 times the bandwidth, is able to receive up to 6GHz, and is also able to transmit. It’s only half-duplex, so to receive and transmit simultaneously you’ll need two HackRFs, or maybe wait for a hardware revision that will hopefully come sooner rather than later.

Below you can check out [Michael]’s presentation at Toorcon where the HackRF was unleashed to the world.

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Retrotechtacular: A Tour Of WLW, A 500,000 Watt Radio Transmitter

July 26, 2013 by Mike Szczys 61 Comments

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This is an overview of a 500,000 Watt radio transmitter site. It’s one of the slides shared in a guided video tour of the transmitter’s hardware. The radio station — whose call sign was WLW — called itself the Nation’s Station because of its ability to reach so much of the country.

It operated at the 500 kW level starting back in the 1930’s. The technology at the time meant that there were a lot of challenges involved with transmitting at this level of power. It took 750 kW input to achieve the 500 kW output. To reach that the station had a set of AC motors in the basement generating the 4500 Amps at 33 Volts DC ~~needed to power the transmitter~~ to heat each filament. Obviously there was a lot of heat generated at the same time. The system was water-cooled. An elaborate network of Pyrex pipes carried distilled water to and from the tubes to handle the heat dissipation.

The video tour lasts about thirty minutes. It’s just packed with interesting tidbits from the experts leading the tour so add it to your watch list for some geeky entertainment over the weekend.

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[Travis Goodspeed] Starts A Space Agency In Southern Appalachia

July 23, 2013 by Mike Szczys 14 Comments

His space agency hardware might be in Southern Appalachia, but he can control it from anywhere in the world. That’s right, [Travis Goodspeed] started his own space agency — well kinda. The first piece of hardware operated by the organization is this dish for tracking moving targets in near space.

The main part of the build is a Felcom 82B dish which was designed to be a satellite link for naval vessels. The image showing the back side of it exposes all of the extras he built into the system. Don’t worry though, a dome goes over the top to keep the weather out without encumbering its operation.He uses an SDR dongle to handle the radio communications. That connects to a BeagleBone which pipes the data to his handheld over the Internet.

It’s amazing to see this type of hobby project. It wasn’t that long ago that you needed an entire room of hardware to communicate with satellites.

Long Distance PS3 Controller

June 19, 2013 by Brian Benchoff 15 Comments

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Sony’s DualShock 3 controller can be seen in a number of projects here on Hackaday. There’s a reason for this: it’s easy to sniff the Bluetooth signals coming out of this controller and make any electronics project do your remote control bidding. Bluetooth has a fairly limited range, though, so what happens if you’d like to use this very comfortable and very functional controller over a mile or so? Just replace the mainboard of the controller with a new design using an Xbee radio. It’s a great project from the workbench of [Marcel] and looks to be just the solution for an awesome Xbee remote control.

The Sony DualShock 3 controller is designed around a single main board for the bulk of the electronics and analog sticks with three daughterboards used for every other button on the controller. [Marcel] took the main board out of his controller and stated to reverse engineer the thing, keeping the USB charging, PC communication, force feedback and LED indicators. Instead of Bluetooth as in the original circuit, [Marcel] used a 60mW XBee radio, allowing him to control just anything connected to another XBee radio with a range of up to a mile.

[Marcel]’s new main board is a direct drop in replacement for the original DualShock 3 mainboard, and the only modification to the controller is drilling a small hole for the new antenna. It’s a great piece of kit for RC vehicles of any kind, and it’s fully programmable for whatever robotics project you might have in mind.

Thanks {Roel] for sending this one in.

Crystal Oven Temperature Sensor Reads 0.01F Resolution

June 19, 2013 by Mike Szczys 17 Comments

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[Scott Harden] continues his work on a high precision crystal oven. Being able to set a precise temperature depends on the ability to measure temperature with precision as well. That’s where this circuit comes in. It’s based around an LM335 linear temperature sensor. He’s designed support circuitry that can read temperature with hundredth-of-a-degree resolution.

Reading the sensor directly with an AVR microcontroller’s Analog-to-Digital Converter (ADC) will only yield about 1-2 degrees of range. He approached the problem by amplifying the output of the sensor to target a specific range. For the demonstration he adjusts the swing from 0-5V to correspond to a room temperature to body temperature range.

Of course he’s using analog circuitry to make this happen. But before our digital-only readers click away you should view his video explanation. This exhibits the base functionality of OpAmps. And we think [Scott] did a great job of presenting the concepts by providing a clear and readable schematic and explaining each part slowly and completely.

So what’s this crystal oven we mentioned? It’s a radio project that goes back several years.

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Telegraph Sounder Clicks Out Email Messages

June 12, 2013 by Mike Szczys 7 Comments

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[Patrick Schless] is excited to show off the project he took on about nine months ago. After finding an antique telegraph sounder he wired it up to an Arduino to see if he could make it tick. The successful experiment laid the ground work for different hardware that would make it into a morse code email reader.

He doesn’t know much about the background of the old hardware, but driving it is relatively simple. It’s basically a magnetic relay so you need to have a transistor for switching and a flyback diode for protection. Once those components are in place it’s just a matter of toggling a bit. [Patrick] knew he wanted to pull messages from an online source, so he set his Arduino aside and grabbed a Raspberry Pi. It worked like a charm. His plan was to put this on a bookshelf in perpetuity so he went the extra mile, designing his own PCB and having it spun using the OSH Park service. The project is finished with this low-profile laser-cut base which houses all of the electronics.

Now if he wants to respond to his emails in Morse code he needs to build this keyboard.

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