Hackaday Links: December 22, 2013


[Korben] is using a picture frame as a Bluetooth speaker (translated). He hacked a Rock’R² for this project. It’s a device that has a vibrating element which can be used to make any hollow item into a speaker.

Entertain yourself over the holidays by mastering the Apollo Guidance Computer simulator. It’s a JavaScript version of the computer used in the modules of the Apollo moon missions.  [Thanks Gregory and Paul]

Here’s a little mirror attachment that lets you use your laptop as an overhead projector. [Ian] calls it the ClipDraw. Affix it to the webcam and use the keyboard as the drawing surface. Since it’s simply using the camera this works for both live presentations and video conferencing. What we can’t figure out is why the image doesn’t end up backward?

This guide will let you turn a Carambola board into an AirPlay speaker.

Those who suck at remembering the rules for a game of pool will enjoy this offering. It’s some add-on hardware that uses a color sensor to detect when a ball is pocketed. The Raspberry Pi based system automatically scores each game.

We spend waaaay too much time sitting at the computer. If we had a treadmill perhaps we’d try building [Kirk's] treadmill desk attachment. It’s made out of PVC and uses some altered reduction fittings to make the height adjustable. It looks like you lose a little bit of space at the front of the belt, but if you’re just using it at a walking pace that shouldn’t matter too much.

You can have your own pair of smart tweezers for just a few clams. [Tyler] added copper tape to some anti-static tweezers. The copper pads have wires soldered to them which terminate on the other end with some alligator clips. Clip them to your multimeter and you’ve got your own e-tweezers.

Measuring SMD parts with a home brew version of Smart Tweezers

SMD parts are great; they allow you to pack more parts on a board, do away with drilling dozens of PCBs, and when done correctly can produce a factory-quality board made in a home lab. There’s one problem with SMD parts; troubleshooting and measuring them. The ideal solution would be something akin to the Smart Tweezers we’ve seen before, but this fabulous tool costs three hundred bones. [Kai] came up with a much cheaper solution: home brew smart tweezers that can be built for a tenth of the cost as the professional model.

What [Kai] built is an LCR meter, basically a tool that measures inductance, capacitance, and resistance in a very, very small form factor. The technique of measuring a part’s properties involves feeding a set frequency into the device and measuring the phase, voltage and current coming out. It’s all wonderfully explained by [Dave] over at EEVblog in one of his earlier videos.

The hardware [Kai] is using includes an LCD display from a Nokia phone, an MSP430-based microcontroller, a very tiny opamp near the tip of one of the points of the tweezer, and a programmable gain amplifier used to measure the components. In testing, [Kai] can measure very low-value components with a +/- 2% accuracy, and larger, more realistic components with +/- 0.25% accuracy. An awesome accomplishment, and much better than the common Chinese meters that can’t measure in the nH/pF/mΩ range.

[Kai] hasn’t gotten his pair of smart tweezers working yet – he still needs to get the circuit up and running and write some software. We’ll keep our readers apprised of [Kai]‘s progress, though, and gently convince him to work with Seeed Studio or someone similar to get his version of Smart Tweezers onto maker’s workbenches the world over.

Tools: Smart Tweezers


We’re big fans of surface mount parts. SMD components are cheaper, take less board space, and don’t require drilling; all the coolest new parts are only available in SMD packages.

Smart Tweezers are an advanced multimeter tool specifically designed to test and troubleshoot SMD circuits. It automatically identifies resistors, capacitors, and inductors, and displays the relevant measurements. Advanced Devices sent us a pair of Smart Tweezers to review. We used them while building our last few SMD projects, read about our experience with this tool after the break.

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