Making capacitive touch sensors with pencil and paper

capacitive-touch-sensor

There are few things more frustrating than being in the middle of working on a project and realizing that you are missing some crucial component that ties the whole thing together. According to Murphy’s Law, this sort of thing will only happen when parts are completely impossible to procure.

If you’re ever hunting for a touch sensor but can’t get your hands on one, [Alan Chatham’s] tutorial on simple DIY capacitive touch sensors might be just what you need to keep things moving along.

[Alan’s] sensors rely on the conductive properties of graphite, which is easily found in just about any pencil on the market. The sensors are created by simply drawing on a piece of paper with a pencil, then wiring the images or text up to your favorite microcontroller via some paperclips and a couple of resistors.

Paper and pencil might not make for the most durable means of input, but we’re pretty sure that [Alan’s] capacitive touch sensors would be very helpful in a pinch. He doesn’t have video of the sensors in action just yet, though he says he’ll put something together here shortly.

An Arduino Based Quadruped Robot

Arduino-Based-Four-Legged-Robot

Sure, we see hexapods all the time at [HAD], but moving around with four legs can be more tricky kinematics-wise. This Instructable shows you how to make one out of balsa wood.

Although one might not think of balsa to make their robot out of [vexedpheonix] explains that this was chosen because it’s extremely light and easy to work with. Since he was trying to keep costs down, the cheapest servos available were used. These weren’t all that powerful, so the lighter the body the better! According to the included bill of materials, he was able to keep the entire robot build under $100.

According to the article, the hardest part was making four copies of the same leg. We might suggest using a CNC router, but building one would obviously add a huge layer of complication to the project!

Thanks for the tip on this one [SteveT]! Be sure to check out the video of this little robot waving one of it’s legs or trying to walk after the break! [Read more...]

Reading RFID cards from afar easily

RFID hacking has been around for years, but so far all the builds to sniff data out of someone’s wallet have been too large, too small a range, or were much too complicated for a random Joe to build in his workshop. [Adam]‘s RFID sniffer gets around all those problems, and provides yet another reason to destroy all the RFID chips in your credit cards.

The project was inspired by this build that took a much larger RFID reader and turned it into a sniffer capable of covertly reading debit cards and passports from the safety of a backpack or briefcase. [Aaron]‘s build uses a smaller off-the-shelf RFID reader, but he’s still able to read RFID cards from about a foot away.

[Aaron]‘s build is very simple consisting of only an Arduino and SD card reader. [Aaron] is able to capture all the data from an RFID card, write that data to the SD card, and emulate a card using his RFID cloner.

What’s really impressive about the build is that [Aaron] says he’s not a programmer or electrical engineer. His build log is full of self-denegration that shows both how humble [Aaron] is and how easy it is for anyone with the requisite skill set to clone the bank card sitting in your wallet. We don’t know about you, but you might want to line your wallet with aluminum foil from now on.

Motorized skateboard just begging to be your next project

You’re not going to be doing any flip-tricks with this board, but it’ll let you get around without getting sweaty. The ZBoard is a motorized skateboard which is in the pre-order stages thanks to a successful Kickstarter campaign. It’ll set you back $500 now or $600 later. With that kind of budget wouldn’t it be fun to build your own?

This base model can go about five miles or five hours between charges. It carries a seal lead-acid battery (really?) but if you upgrade to the pro model for just $250 more you get a LiFePo that doubles the range (but curiously not the run time). To make it go there are pressure sensitive foot pads on the front and rear of the deck. This allows you to go slow with just a bit of pressure, or put the pedal to the metal to get up to the 15 mph speed limit. It’s even got regenerative breaking to slow things down while giving a boost to the battery.

The idea is nothing new. But the cleanliness that this product brings to market is something to be respected. We’re hoping this sparks some inspiration for a rash of DIY clones, kind of like we’ve seen with the Segway.

[Read more...]

Reading wax cylinders with lasers

From 1902 to 1905, Polish anthropologist [Bronislow Pilsudski] did a series of recordings in Hokkaido japan on wax cylinders. Researchers at the university of Hokkaido have been working on ways to read the cylinders without causing any further damage to the grooves. Their preferred method has been to use reflected laser light. They have a very short writeup on their configuration, but it should be enough to get the idea.

Another project they’ve taken on is reading the original molds as well. They had to completely reconfigure their device to be able to be inserted into the cylinder. The quality they get from those is far superior though.

 

Ask Hackaday: Troll Physics Super Deluxe Edition

Here’s a brain bender for you: YouTube user [Fredzislaw100] put up a video of six LEDs and six switches wired up in series. After soldering a resistor and 9V battery connector, the first switch turns on the first LED, the second switch turns on the second LED, and so on for the rest of the circuit.

We’ve seen this trick before from [Fredzislaw100], only this time he’s moved up from 3 LEDs to 6. In the reveal of the previous trick, [Fredzislaw] built two AC power supplies inside a nine volt battery connector; one high frequency and one low frequency. The low frequency AC line powers the first two LEDs with the help of diodes in the switches and LEDs. The high frequency AC line turns on the third LED with the help of an inductor inside an LED. Apparently [Fredzislaw] still has some soldering skills to show off; the circuit powering this trick is most likely the work of a soldering god.

From a close viewing, it looks like LEDs are wired up in pairs, i.e. LED 1 works the same as LED 2, LED 3 works the same as LED 4, etc. We’ll let Hackaday readers argue it out in the comments as to how this trick is possible.

Tip ‘o the hat to [Th0m4S] for sending this one in.

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