THP Semifinalist: A Continuous Wave Radar

radar

There aren’t many Hackaday Prize entries playing around in RF, save for the handful of projects using off the shelf radio modules. That’s a little surprising to us, considering radio is one of the domains where garage-based tinkerers have always been very active. [Luke] is bucking the trend with a FM continuous wave radar, to be used in experiments with autonomous aircraft, altitude finding, and synthetic aperture radar imaging.

[Luke]‘s radar operates around 5.8-6 GHz, and is supposed to be an introduction to microwave electronics. It’s an extremely modular system built around a few VCOs, mixers, and amplifiers from Hittite, all connected with coax.

So far, [Luke] has all his modules put together, a great pair of cans for the antennas, everything confirmed as working on his scope, and a lot of commits to his git repo.

You can check out [Luke]‘s demo video is available below.


SpaceWrencherThe project featured in this post is a quarterfinalist in The Hackaday Prize.

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Guest Post: Try Radar for Your Next Project

greg_sar_radar

(photo taken by Matt Metts)

Sensors. The low-end stuff that we can get our hands on usually suffers from poor range, lack of sensitivity, and no way to characterize what the target is. But today we can use the good stuff that, until recently, was only available to military: radar. In this post we will discuss how radar works, commercially available small radar devices, and where to learn more to help make it easy to add radar to your next project. Reach out and sense something!
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Morse code beacon wins the LayerOne badge hacking contest

Ham skills prevail in this year’s LayerOne badge hacking contest. [Jason] was the winner with this Morse Code beacon hack.He got a head start on the competition after seeing our preview feature on the badge hardware development. It got him thinking and let him gather his tools ahead of arrival.

The hardware is segregated into two parts of the board. The lower portion is a take on the Arduino, and the upper portion is a wireless transmitter meant to control some cheap RC cars. [Jason] figured this was perfect for conversion as a CW beacon (continuous wave is what Morse Code is called if you’re a ham). The first issue he encountered was getting the badge to play nicely with the Arduino IDE. It was setup to run Slowduino firmware which uses the internal oscillator. [Jason] soldered on his own crystal and reflashed the firmware. He found that the transmitter couldn’t be directly keyed because of the shifting used in the RC car protocol. He cut the power to the transmitter, and found that it could be more accurately keyed by injecting power to one of the other pins. Check out the video after the break for a better explanation of his technique.

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Fine tune your Morse Code skills with this mint tin practice keyer

mint-tin-keyer

Hackaday reader [svofski] wrote in to share a device he built, which would be useful to any ham operators out there trying to hone their CW skills. He calls his practice keyer the Morseshnik, and it is a combination of various items [svofski] found while digging through his parts drawer.

He disassembled an old hard drive, saving its read arm to serve as the keyer’s paddle. He purchased some small angle brackets to create a set of contacts for the device, between which the lever sits, automatically centered by a pair of springs.

An MSP430, which was also collecting dust in [svofski’s] junk pile, resides inside the Morseshnik’s mint tin base on a small DIY PCB. It allows him to toggle between manual and automatic keying modes with the flick of a switch as he whiles his time away practicing his dits and dahs.

Continue reading to see a short video of the Morseshnik in action, and swing by his site for code and PCB schematics should you want to build one of your own.

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Using a touch sensor as a telegraph key

[Sebastian] is learning Morse code and CW radio, and of course he needed a telegraph key. Instead of using the terribly unergonomic paddle style key, he built a capacitive touch iambic key over the course of a few evenings.

An iambic key usually has two switches. When one switch is closed, it will transmit a ‘dit’. When the other switch is closed, it will transmit a ‘dah’. Instead of using mechanical paddles, [Sebastian] brought his iambic key into the 21st century by using a touch sensor. An ATtiny45 measures the time it takes for a single metal plate to fully charge. It’s the same idea behind the wonderful Arduino CapSense library.

This isn’t the first capacitive-touch iambic key we’ve seen; this little guy is just a pair of metal contacts and resistors that plug right into an Arduino. With an ATtiny45, [Sebastian]‘s build is a full-blown iambic telegraph key that plugs right into his CW rig. You can check out the walk through of the project along with [Sebastian] trying out his iambic key after the break.

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An iambic keyer in 5 minutes

When most people think about a telegraph key, a piece of 1890s tech with a lever that moves up and down comes to mind. These ‘straight keys’ were terrible for telegraphers and led to repetitive stress injuries like carpel tunnel syndrome..Iambic keys came along and move the contacts to a horizontal position. If you ever see a HAM playing with his CW rig, chances are they’re using an iambic key. It’s great, then, that you can build your own iambic key in five minutes using parts you have lying around.

The build [Dimitris] put up is dead simple – just two metal contacts with a pair of 470K pullup resistors. All this connects to three pins on an Arduino. All the micocontroller needs to do is measure the rise time a touch sensor pin when a voltage is applied. If there’s a finger on the pin, the capacitance increases and the rise time is longer. After that, just assign one sensor as ‘dit’ and the other as ‘dah’ and you’ve got an iambic key.

[Dimitris] put all the code for his project up on his blog. His iambic key seems like the perfect project after a tiny Morse trainer. Check out the video of the key in action after the break

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PIC-based Ham radio autotuner

cw_autotuner

A few years back, [Floyd, K8AC] built a high frequency autotuner as an addition to his Ham radio setup. Based off a design he saw in QST magazine back in the early ’90s, he has been using the tuner almost daily for the last few years, on both the 3.5 MHz and 7 MHz bands.

Built into the wall in his radio room, it is a pretty impressive sight. His “L” circuit is controlled by a pair of mechanically coupled inductors which are driven in concert by a pair of two-way motors. The positioning of the C and L components are monitored by a PIC controller which stores the tuning data for up to 30 predefined frequencies. A couple of button presses on his controller’s front end sends the tuner into action, dialing in his unit’s inductors and capacitor to their proper settings. The PIC monitors the tuner’s progress, informing him when the proper frequency has been tuned in, or if the frequency can not be set, indicating issues with the equipment.

His setup has undergone several revisions over the years, with the most recent iteration being the most automated of the bunch. Check out his site for plenty more details, or keep an ear out for [K8AC] on 40 or 80 meters.

[Thanks, Rich V]

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