Hellduino: Hellschreiber radio transmissions from an Arduino board

[Mark VandeWettering] was experimenting with a simple transmitting circuit and an Arduino. The circuit in the project was designed by [Steve Weber] to broadcast temperature and telemetry data using Morse Code. But [Mark] wanted to step beyond that protocol and set out to write a sketch that broadcasts using the Hellschreiber protocol.

This protocol transmits glyph images, which are decoded as you see above. For some reason we can’t help but think this is like Captcha for radio enthusiasts. We have seen Hellschreiber used with AVR microcontrollers before, but this is the first Arduino implementation that we’ve come across. [Mark] does a great job of demonstrating his project in the video after the break. He mentions that the transmitter has no antenna, but is still being picked up by his receiving antenna mounted behind his house.

Since [Mark] doesn’t really cover the hardware he used, you will need to look back at [Steve's] original design schematics for more information.

[Read more...]

Hackaday Links: November 10, 2011

Experimentations with haptics

[Chris] sent in two videos (1, 2) documenting his experiments with haptic feedback. He’s recording the position of a DC motor and can either play it back or send it to another motor. It’s very similar to the kissing robot we saw earlier this year, but we’re not making any judgments.

Mobile Emergency Repeater go bag

[Nick], a.k.a. [KF5JAK] sent in a few pics of his emergency/disaster relief amateur radio go bag. With a 3G connection via a cell phone, the MER can be used with EchoLink.

Launchpad MIDI booster pack

Earlier this month we lamented the dearth of add-ons for the TI Launchpad. The folks on the 43oh forums just came out with a MIDI booster pack. Time to dust off that old Radio Shack keyboard, we guess.

Macro photography with OH GOD WHARGARBL

You know camera lenses work both ways, right? [Karl] has been experimenting with this very idea by mounting a camera lens backwards and running a few wires so it’s electrically connected as well. Check out an example shot.

Keeping tabs on your kids’ homework

[Janis] doesn’t live with his kids but he wanted to keep track of their homework. He set up a document scanner that sends those worksheets straight to his email inbox. All he has to do is annotate them and send them back. This guy’s doing it right.

Beating the wrong amateur balloon record

Friday, we covered a little project that attempted to beat the UK altitude record for an amateur balloon launch. Things don’t always go as planned, but the APEX team did manage to beat the several other UK records, including ones for the longest distance and flight duration for a latex balloon.

The APEX team was originally trying to beat the altitude record set by [Darkside] and his Horus 15.5 payload that made it to 40,575 meters. The APEX balloon was launched and slowly climbed over the North Sea to the expected burst point. Unfortunately for the trackers, the balloon leveled off at about 36km and just kept going.

The total Great Circle distance of the APEX Alpha flight was 1347km, with a total flight time of 12 hours, 20 minutes. The balloon eventually drifted out the radio range of anyone aware of the project. Despite the valiant efforts of HAMs across Europe, APEX Alpha was lost in the “HAM wastelands of Eastern Europe,” somewhere over Poland.

Even though the APEX team lost contact with their balloon, Alpha was still transmitting at the time. The balloon surely burst at this point, so it could have landed anywhere from Poland to Ukraine to Russia. The APEX team is offering a reward for finding Alpha, so if you see a small styrofoam box in Eastern Europe, drop the APEX boys a line.

Of course this flight couldn’t have taken place without the efforts of HAMs across Europe. [Darkside], [2E0UPU], and so many others helped out with the tracking as Alpha passed over the Netherlands and continued towards Berlin. The last contact was made by the awesome [OZ1SKY], who was very gracious to stay up until the wee hours of Sunday morning.

Not a bad flight for something that was supposed to take a swim in the North Sea. If you’d like to see the raw data from the flight, the APEX team posted everything they pulled down.

Turning a router into an APRS gateway

[Chris Kantarjiev] is an amateur radio enthusiast (call sign K6DBG) and does a lot with the APRS. We think his build, turning a WRT54gl router into an APRS gateway will be very useful for the APRS tracker builds we’ve been covering.

Setting up an Internet Gateway, or igate, on APRS usually requires a ‘real’ computer. [Chris] didn’t like that idea, so he took aprs4r, igate software for embedded devices, and pruned it down to fit on the 4MB of flash and 16MB of RAM in the WRT.

The actual APRS hardware is connected though headers soldered onto the WRT54gl’s board which go to a small PIC-Based TNC. [Chris] argues that the APRS ‘backbone’ is great, but there aren’t enough nodes on the network for full coverage. We thing this would be a great way to put cheap hardware out in the wild to cover those gaps in the APRS network.

Check out the video for a rundown of the modded WRT54g after the break. If you’re interested amateur radio, Field Day is coming up in just 2 weeks. Find a local club and check out what’s possible with amateur radio.

[Read more...]

Building a better spectrum analyzer for radio enthusiasts

This spectrum analyzer project seeks to improve the quality of tools available to amateur radio operators. A lot of thought has gone into the design, and those details are shared in the verbose project log. The case was originally a CATV link transmitter, but most of the controls seen above have been added for this build, with unused holes filled and finished to achieve the clean look.

One noteworthy part of the build is the time that went into building a rather complicated-looking 1013.3 MHz cavity bandpass filter. Despite the effort, the filter didn’t work. Details are a bit sketchy but it seems that some additional tuning brought it within spec to complete that portion of the device.

This certainly makes other toy spectrum analyzers look like… toys.

[Thanks William]

Balloon based satellite

balloonsat

This project provides an opportunity to conduct near space experiments. The flight computer, BalloonSat Extreme, is controlled by a BASIC Stamp 2pe. The complete BOM with PCB artwork is provided. There is enough hardware to control cameras, servos, a Gps, and five digital I/O. The computer is also equipped with a 12 bit ADC to log experiment results. The device seems limited to 30KB of storage. Though the author suggests this memory limitation is more than adequate, we are wondering if an implementation of the Nyquist sampling theorem is in use at all. For further reading the author has provided information regarding Amateur Radio High Altitude Ballooning.

[via adafruit]

QRSS: Radio amateurs’ slow-speed narrowband

qrss

Host of the Soldersmoke podcast, [Bill Meara], contributed this guest post.

While the rest of the world is moving toward high speed broadband, some hams—including one Nobel Prize winner—are going in exactly the opposite direction. Our ‘QRSS’ mode makes use of an unusual mixture of modern digital signal processing (DSP), ancient Morse code, and simple homebrewed transmitters. Very narrow bandwidth is desirable because this reduces the noise in the radio communication channel, greatly improving the S/N ratio.  But Shannon’s communication theory tells us that narrow bandwidth comes with a cost: slow data rates. In QRSS, beacon transmitters using only milliwatts churn out slow speed Morse ID signals on 10.140 MHz that are routinely picked up by DSP-based receivers on the other side of the globe. Many of the receivers, ‘grabbers’, have visual outputs that are available online in real time. QRSS has been getting a lot of attention on the Soldersmoke podcast and on the Soldersmoke Blog. For more information check out this overview and the hardware involved. Here’s a gallery of received signals.