555 Based AM Radio Transmitter

January 10, 2011 by Mike Szczys 33 Comments

Bust out that 555 timer and use it to build your own AM radio transmitter. The circuit that [Rtty21] is using only needs the timer chip, an NPN transistor, three caps, three resistors, and a potentiometer. It generates an amplitude modulation signal around the 600 kHz range which you will be able to pick up with any normal AM radio. From the comments on the article it seems you’ll get around 30-40 feet of range out of the device. We don’t see this as a competitor for the FM spy microphone, but maybe you can use it as a diy baby monitor.

Beer Catapulting Fridge

January 10, 2011 by Caleb Kraft 21 Comments

We’re not sure where the fascination to have your libations flung at you came from, but we can’t say we’re entirely against it. This beer catapult robot (dead link try Internet Archive) will pull a cold one from its gullet and fling it to you, or in your general direction. While he doesn’t have the source code available for the Arduino bit, we’re OK with that. We’re more interested in the mechanisms at work here and there are plenty of pictures of his set up. It seems very similar in design to this one we covered back in 2007, which also appeared on” The Late Show with David Letterman”. Join us after the break to see the thing in action.

[thanks Springuin]

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Reverse Geocache Features UI And Is Reprogrammable

January 9, 2011 by Mike Szczys 7 Comments

Here is yet another offering in the Reverse Geocache puzzle arena. We’ve been getting a lot of tips about these projects but this one in particular stuck out from the others. [Mure] packed in a bunch of features, starting with the LCD screen seen above. You can just make out the single red button near the bottom of the image which is used to traverse the menu. The octagonal box has an octagonal PCB inside that includes a USB connector. As you can see in the video after the break, this can be used for charging the batteries, and communicating with the internals. An accompanying program is used to generate puzzle data, which can then be programmed via that USB connection to set a new puzzle location. This functionality certainly protects against accidental lock-outs which were a problem with the last puzzle we looked in on.

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OLED Displays And Small Microcontrollers

January 9, 2011 by Mike Szczys 22 Comments

If you’ve ever thought of utilizing a small and inexpensive OLED display in your project [Rossum] has the details you need to get started. In the past we’ve seen him take a tour of available LCD screens and this is much the same, detailing his look at three different models. In the video after the break each is connected to a driver board that he made. The boards have two important components, the first is a boost driver for the 12-16V input the screens need, the second is an octal buffer necessary if you are using a 5V microcontroller. These take care of the hardware considerations, making it simple to drive them with a chip of your choosing.

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Data Logging Football

January 9, 2011 by Mike Szczys 6 Comments

[Ben Kokes] threw together a hardware package to capture data from a football. In the center of a Nerf football he made room for an accelerometer, gyroscope, and an electronic compass. All three can capture 3-axis data and, along with the LEDs ringing the circumference, they’ve controlled by an XMEGA192 microcontroller.

This makes us think back to a time when baseballs with a built-in speed sensor first hit the market… does this hack have mass marketing potential? Perhaps, but only if the $225 sensor price tag were greatly reduced. When we first started reading the description we hoped that [Ben] had coded an interpreter that would render 3D playback video from the data. He hasn’t done that, but from the data graphs he did assemble we don’t think that functionality is out of the question. We’ll keep our fingers crossed.

Steam Cycle Feels Like Your Pants Are On Fire

January 8, 2011 by Mike Szczys 54 Comments

Usually we don’t like to feature projects that have zero build details, saving them instead for a links post. But this steam-powered bicycle is too… peculiar to pass up. In between the rider’s legs is the firebox that contains a wood-fueled fire. Watch the clip after the break and you’ll find just how noisy this contraption can be. In addition to the mid-range “chug-a chug-a” there’s also the constant whistle we’d attribute to the pressure regulator. It’s surprising that the whole bike doesn’t heat up, but it must not be all that bad since the test pilot isn’t wearing asbestos pants. All kidding aside, it looks like this beast has no problem getting up to a running pace (based on the movements of the camera) and that’s thanks to a renewable energy source.

We’d be much more comfortable seeing this in a mechanized tandem form factor since we just can’t get over having a fire between our legs.

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PIC Spectrum Analyzer Uses Fast Fourier Transform Routine

January 8, 2011 by Mike Szczys 29 Comments

[Simon Inns] just rolled out his latest project, a PIC based spectrum analyzer. He’s using a Fast Fourier Transform routine crafted in C to run as efficiently as possible on the 8-bit chip. The video after the break shows that the results are quite pleasing, with just a bit of noticeable lag between the sound and the waveform representation on the graphic LCD. We found his notes about using an audio amplifier chip to be interesting. He utilizes the properties of an LM386 to move the input signals from a range of -0.5V to +0.5V into a very ADC friendly range of 0-5V.

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