Building a simple FM transmitter bug

simple_fim_transmitter_hack_a_week

[Dino] got his hands on an FM transmitter “bug” kit via a friend, and thought it would make for an easy and fun Hack a Week project. The kit is simple two transistor half-wave FM transmitter, which the manufacturer suggests could be used to bug a room, hence the name. After poking a bit of fun at the instructions, [Dino] gets to work building the transmitter, wrapping things up in a little less than an hour.

Once he finished soldering everything together, he takes a few moments to test out the bug and to explain how various parts of the board work together in order to transmit the FM signal. He mentions that adding a dipole antenna would make it easy to extend the range of the transmitter, and briefly teases next week’s episode, where he plans on constructing a similar dual-stage transmitter.

This sort of FM circuit is one of the first few simple projects you would see in a beginner’s electronics class, so if you know anyone that is just starting to get their feet wet, be sure to pass this Hack a Week episode along.

Continue reading to see [Dino] explain the ins and outs of his FM bug transmitter.

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BAMF2011: Bloxes, a building kit with a nifty pedigree

Not every cool hack needs to involve microcontrollers, LEDs or other bling. We were initially drawn to the Bloxes display simply because we love a good multipurpose construction set, whether it be Lego, 80/20 aluminum, or in this case, a system of interlocking cubes formed from six identical pieces of corrugated cardboard, cut and scored in such a manner as to form a surprisingly sturdy little building block. They can become simple furniture, groovy Logan’s Run-style room decor, or the all-important kids’ forts…then later dismantled and made into something else.

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Free (…as in ‘free beer’) ARM kit

NXP holds a lot of market share for their ARM based solutions as it is. That’s why we were a little surprised when we found a link on their website announcing that they were giving away free LPCXpresso development boards, based on their Cortex-M0 line.

Catches? Unfortunately there are a few to get the board shipped and running. In order to do so, you must…

  • register with a corporate email address
    …the promo is targeted at engineers
  • use the crippled IDE supplied with the board
    …due to hard to find (non-existent?) documentation for the integrated LPC-Link
  • upload an original video of the physical destruction of a competing board to the NXP website

While killing your Arduino may not sound like the most fun, some qualified readers may be interested in moving up to 32-bits for a price that is hard to beat.

Pin header sizing machine

[Ammon Allgaier] built a tool that can break apart pin headers with a high level of precision. In the video after the break he demonstrates the built-in features. They include an adjustable stop to select the number of pins you’d like in each chopped segment. There’s also a small groove in the input side which the plastic frame of the header rides in. Just insert until it is touching the stop, and push down to break the header at the correct location. A couple of springs return the cutting tooth to its resting position, allowing you to make quick work of chipping up a 40-pin blank. This machine will become a nice companion for that automatic wire cutter.

This is great for single headers but we’ve long been on the lookout for a reliable way to snap off double pin headers. Far too often we make mistakes when trying to use two pair of pliers. If you know of a better way, please share your method in the comments.

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Solar monsters… you know… for kids!

Teaching kids to solder using kits is a fun time, but most of these beginner kits are a bit mundane. Not this one, it’s a solar-powered monster project. The components and their wiring connections are printed on a sheet of paper along with a background for that particular monster. The base of the paper is glued to a block of wood and at each solder junction there’s a copper nail. This way the kids can line up the components, check the picture to make sure the polarization is correct for each, then solder onto the large and stable nail head. As you can see in the video after the break, when the solar cell collects enough electricity the transistor triggers a motor to spin the monster.

But don’t get the idea that kits are only for kids. If you haven’t tried your hand with SMD soldering yet, this kit is for you.

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Update: Atari pause button

The Atari 2600 pause circuit is now available in a kit form. We saw this pause method back in February and the kit uses the same circuit. We don’t really need a kit for this, the board is very simple to throw together. But we do appreciate the detailed installation instructions (PDF) that accompany it. After all, you don’t want to kill you classic gaming rig with a botched install.

[Thanks CPUWIZ]

Headphone tube preamp kit

If you’re curious about tube amps but don’t have a firm enough knowledge base to dive right in you might want to try a kit. [Mark Houston] reviewed one such kit and we enjoyed reading about his experiences. It comes with everything you need save soldering tools, an enclosure, and the final connectors ([Mark] used RCA connectors). There is a full schematic available and the assembly instructions take you through tube matching and using that piece of copper coil you see in the picture to wind your own inductor. Consider trying this primer before you jump into building a single tube, multiple tube, or an amplifier of your own design.

[Thanks Gio]