Crystal Radio: It’s A Match!

September 5, 2015 by 10 Comments

A crystal radio is often a kid’s first introduction to building something electronic. [Billy Cheung] is a crystal radio builder who wants to “make crystal radios as easy to use as regular radios.” He’s built many sets, but his latest is one that not only fits in a matchbox, but uses the matchbox as a variable tuning inductor.

There’s no oatmeal box in this design and just a few components. The matchbox contains some ferrite rods and two different windings. By moving the inner part of the matchbox, you can tune different stations. Although the design calls for two fixed capacitors [Billy] found he had enough self resonance (presumably from stray capacitance) that omitting them didn’t hurt his reception of strong signals.

Continue reading “Crystal Radio: It’s A Match!” →

arduino alarm panel

Upgrading Your Alarm System With An Arduino

September 5, 2015 by 17 Comments

When [Doug] moved into his new house, he found an old alarm panel set up — but it had no monitoring service any more. Not wanting to pay a monthly fee to have it setup, he decided to try interfacing an Arduino with the system in order to push events to the net!

The cool thing is he was actually inspired by another similar project we shared on Hackaday a few years ago entitled Bending a Home Security Control Panel to Your Will. But that project only showed you how to interface the Arduino with the keypad — [Doug] went the extra mile and interfaced directly with the control board for more features.

He’s using an Arduino Uno and an Ethernet breakout board to hook it up to the network. This allows him to send text messages to himself when the alarm system is armed, disarmed, or triggered. All the code is available on GitHub in case you also have a DSC 1550 alarm system.

It’s a pretty slick hack, so don’t forget to check out the video after the break.

Continue reading “Upgrading Your Alarm System With An Arduino” →

How To Make A Hugo (Base)

September 5, 2015 by 25 Comments

A lot of hackers like science fiction. If you aren’t one of them, you might not know that the Hugo is a prestigious science fiction award handed out at the World Science Fiction Convention every year. The statue looks like a rocket ship, but every year the base the rocket ship rests on is different. Kinetic sculptor [gfish] realized the convention would be in Spokane (his hometown and near his current residence) and decided to enter the competition to create the bases. He won, so the 2015 Hugos all have [gfish’s] bases on them and it’s pretty neat that he’s shared the process he used to make them.

Continue reading “How To Make A Hugo (Base)” →

Scanning Electron Microscope Images And Animations Pulled By Impressive Teensy LC Setup

September 5, 2015 by 29 Comments

When you’ve got a scanning electron microscope sitting around, you’re going to find ways to push the awesome envelope. [Ben Krasnow] is upping his SEM game with a new rig to improve image capture (video link) and more easily create animated GIFs and videos.

The color scheme of the SEM housing gives away its 80s vintage, and the height of image capture technology back then was a Polaroid camera mounted over the instrument’s CRT. No other video output was provided, so [Ben] dug into the blueprints and probed around till he found the high-resolution slow scan signal.

To make his Teensy-LC happy, he used a few op-amps to condition the analog signal for the greatest resolution and split out the digital sync signals, which he fed into the analog and digital ports respectively. [Ben] then goes into a great deal of useful detail on how he got the video data encoded and sent over USB for frame capture and GIF generation. Reading the ADC quickly without jitter and balancing data collection with transmission were tricky, but he has established a rock-solid system for it.

Continue reading “Scanning Electron Microscope Images And Animations Pulled By Impressive Teensy LC Setup” →

Slimline USB Charger For Tiny Ham Radios

September 5, 2015 by 12 Comments

The recent trend to smaller and smaller handy talkie (HT) transceivers is approaching the limits of the human interface. Sure, engineers could probably continue shrinking the Baofeng and Wouxun HTs further, but pretty soon they’ll just be too small to operate. And it’s getting to the point where the accessories, particularly the battery charging trays, are getting bulkier than the radios. With that in mind, [Mads Hobye] decided to slim down his backpacking loadout by designing a slimline USB charger for his Baofeng HT.

Lacking an external charging jack but sporting a 3.7 volt battery pack with exposed charging terminals on the rear, [Mads] cleverly capitalized on the belt clip to apply spring tension to a laser-cut acrylic plate. A pair of bolts makes contact with the charging terminals on the battery pack, and the attached USB cable allows him to connect to an off-the-shelf 3.7 volt LiPo USB charger, easy to come by in multicopter circles. YMMV – the Baofeng UV-5R dual-band HT sitting on my desk has a 7.4 volt battery pack, so I’d have to make some adjustments. But you have to applaud the simplicity of the build and its packability relative to the OEM charging setup.

This isn’t the first time we’ve seen [Mads] on Hackaday. He and the FabLab RUC crew were recently featured with their open-source robotic arm.

Orange Is The New ($15) Pi

September 5, 2015 by 105 Comments

When the Raspberry Pi came on the scene it was hard to imagine that you could get a fairly complete Linux system for such a low price. The Pi has gotten bigger, of course, but there are still a few things you miss when you try to put one into a project. Wifi, comes to mind, for example. The first thing you usually do is plug a Wifi dongle in, consuming one of the two USB ports.

The Orange Pi is a direct competitor and has a few variants. Originally, the board cost about $30 but sports WiFi, a 1.6 GHz processor, 8 GB of flash, and a SATA interface. There’s now a reduced version of the board for about $15 that deletes the flash and SATA along with the WiFi and one of the original’s 4 USB ports. Still, the Raspberry Pi doesn’t have built-in flash. And the $15 Orange Pi PC has the things you’d expect on a Pi (HDMI and Ethernet) along with other extras like an IR receiver and an on-board microphone. Not bad for $15 considering it has a quad-core processor, a GPU and 1GB of RAM. Continue reading “Orange Is The New ($15) Pi” →

Hackaday Prize Semifinalist: A Low Cost, DIY Fuel Cell

September 4, 2015 by 63 Comments

Electronic cars and planes are the wave of the future, or so we’re told, but if you do the math on power densities, the future looks bleak. Outside of nuclear power, you can’t beat the power density of liquid hydrocarbons, and batteries are terrible stores of energy. How then do we tap the potential of high density fuels while still being environmentally friendly? With [Lloyd]’s project for The Hackaday Prize, a low cost hydrogen fuel cell.

Traditionally, fuel cells have required expensive platinum electrodes to turn hydrogen and oxygen into steam and electricity. Recent advances in nanotechnology mean these electrodes may be able to be produced at a very low cost.

For his experiments, [Lloyd] is using sulfonated para-aramids – Kevlar cloth, really – for the proton carrier of the fuel cell. The active layer is made from asphaltenes, a waste product from tar sand extraction. Unlike platinum, the materials that go into this fuel cell are relatively inexpensive.

[Lloyd]’s fuel cell can fit in the palm of his hand, and is predicted to output 20A at 18V. That’s doesn’t include the tanks for supplying hydrogen or any of the other system ephemera, but it is an incredible amount of energy in a small package.

You can check out [Lloyd]’s video for the Hackaday Prize below.

The 2015 Hackaday Prize is sponsored by:

Continue reading “Hackaday Prize Semifinalist: A Low Cost, DIY Fuel Cell” →