An Exercise In Servo Voice Control With Android

November 20, 2011 by Mike Nathan 2 Comments

voice-controlled-android-lock

[Shazin] had some free time on his hands, so he settled in to do something he had been meaning to for a while – learn Android programming. He went an indirect route, and ended up using the Scripting Layer for Android (SL4A), which gave him a head start on the process. Sitting in between the Android API and scripting languages such as Python, SL4A allowed him the ability to apply something he was already familiar with to the Android environment.

He thought it would be cool to try building a door entry system which relied on voice commands to lock and unlock. Using the Google Voice API for Android and an Arduino, he built a small Python application that allows him to toggle a servo simply by talking into his phone.

The application on his phone communicates with an Arduino over WiFi, once Google Voice has decoded the command [Shazin] is giving. The Arduino controls a servo, which in theory could control the locking mechanism on a door.

After a bit of tweaking and some added security, his proof of concept could definitely come in handy.

Check out the short video below to see [Shazin’s] voice-controlled servo in action.

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This Giant Hand Made LED Matrix Must Be Ours!

November 20, 2011 by Mike Nathan 16 Comments

giant-led-matrix

[Martin] wrote in to share a project his company has been working on for some time, a gigantic 1470 pixel LED wall. The group provides lighting for clubs, parties, etc, and their hand-built LED matrix is always certain to be the hit of the show.

The amazing matrix was designed from the ground up and built by hand in [Martin’s] living room. They designed small 32x32mm “pixel” boards, each of which features 6 PLCC6 RGB LEDs driven by a single WS2801 LED controller. The PCBs were populated by hand and each one was reflowed in a small pizza oven that [Martin] owns. After the pixels were completed, they were attached to aluminum bar and combined to build thirty 70x70cm frames which are connected together to form a giant matrix.

As you can see in the collection of videos below, the display is very impressive. We just hope that they will be compelled to release the schematics for their boards so that we can build one of these in the office.

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Getting Useful Data From A Dirt Cheap RFID Reader

November 19, 2011 by Mike Nathan 21 Comments

cheap-rfid-reader

[Aaron] was looking for a cheap RFID reader that had some easy to follow documentation and a standardized interface. Most everything he saw was pretty expensive, so he decided to buy a cheap $10 reader from eBay to see how easy it would be to work with.

The reader came with very little documentation, but [Aaron] did know that the device identifies itself as a USB keyboard, outputting scan tag data into a text editor. That functionality wasn’t incredibly useful, so he took it apart to see if he could interface with it in some other manner. Exposing the PCB revealed an unknown IC for which he could find no documentation, but the board did include some breakout pins, so [Aaron] started by probing those for data.

He tried reading the data in both a terminal program and with a logic analyzer, but nothing seemed to make a whole lot of sense. He turned the sampling rate of the sniffer down, and things started looking a little better. After comparing the data from the sniffer with known tag codes, he noticed that each digit had an offset of 39 applied, so he whipped up a bit of code to correct the numbers.

[Aaron] did a good amount of legwork to get usable data from the reader, but at a cost of $10 it can’t be beat. We certainly know what we’re going to be hunting for on eBay this afternoon…

Python Powered Sprinkler System Wastes No Water

November 19, 2011 by Mike Nathan 31 Comments

rain-gauge

One thing that annoyed [Jashua] to no end was hearing his automated sprinkler system kick on in the middle of the night, when it had rained earlier in the day. He wished that his sprinklers were a bit smarter, so he decided to give the system an upgrade.

Rather than pay hundreds of dollars for a more sophisticated automation system, he spent about $45 on supplies and scrounged together some items he had sitting around the house to make a rain-sensing module of his own.

The resulting project, Pysprinklers, uses Python along with a handful of components to better manage his water usage. He got his hands on a cheap rain gauge, and modified it with a game controller and a set of magnetic surface contacts. If there has been a significant amount of rain in the last 24 hours, his system will prevent the sprinklers from turning on. Additionally, if there is rain in the forecast, the sprinklers will be delayed a bit to see if rain makes its way into the area.

We’re all for saving money (and water), so we think [Jashua’s] system looks great, especially because he ended up using a handful of things he already had on hand.

A DIY Audio Player For When All That Matters Is The Music

November 18, 2011 by Mike Nathan 16 Comments

orange-mepod

[Grissini] hasn’t had the best of luck when it comes to personal audio players. He estimates that he’s gone through about half a dozen iProducts/iKnockoffs over the years, which ultimately adds up to a lot of money poured right down the drain. Rather than lay down his cold hard cash for yet another music player that would succumb to a dead battery or cracked screen, [Grissini] decided that he would be better off if he built one himself.

His Orange mePod isn’t exactly the most attractive or sleekest music player out there, but [Grissini] says it works like a charm. An Arduino Uno powers the device, and he uses an Adafruit Wave Shield to handle the audio playback. Power is supplied via 4AA batteries which keep the tunes going for a reasonable amount of time, and afford him the ability to swap them out for recharging without much fuss.

The player was encased with some leftover cardboard and wrapped in bright orange duct tape, before being mounted on [Grissini’s] belt. He says he gets plenty of looks when he’s out and about, which you would expect from such a unique design.

Stick around to see a quick video of the audio player in action.

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Lighting LEDs With Raindrops

November 18, 2011 by Mike Nathan 40 Comments

[Steven] had one of those musical gift cards laying around, and thought he might as well reuse the piezo speaker inside it. Without a particular project in mind, he soldered an LED to the piezo and tapped on it, which caused the LED to illuminate as expected. He started to wonder what quantity of force would be required to light the LED, and if it could be done by a raindrop.

He first tested his theory in the shower, and as you can see in the video below it actually worked, though the light was dim and sporadic as you might imagine. He eventually discovered that for optimal lighting, the piezo worked best when struck by single droplets falling with pauses in between, from a minimum height of 4 feet. To achieve a water flow within those specifications, he built a rain funnel so that he can control the droplet frequency and intensity.

It seems to work pretty well from what we can see. Off the top of our heads we can’t seem to come up with any practical applications of the water powered LED, but it is an interesting set of experiments nonetheless.

Have an idea to use this setup that we totally missed? Let us know in the comments!

[Thanks, Rob]

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A Head-mounted Tesla Coil – What Could Possibly Go Wrong?

November 18, 2011 by Mike Nathan 26 Comments

We can hear the commercial now…

“Reeeeeeal men of geniuuuuuuus! Here’s to you Mr. no-fear, singing Tesla coil on your hat wearing guy…”

Call him a genius or call him crazy – all we know is that [Tyler’s] Tesla coil hat is awesome! Even though it’s the middle of November, we couldn’t pass up this Halloween costume.

[Tyler’s] creation essentially boiled down to taking a standard dual resonant solid state Tesla coil and shrinking it down to a reasonable size for mounting on his skull. The mini Tesla features a pretty compact boost core which worked reasonably well, at least for a little while. He says that the boost never truly worked properly and needs a redesign, which is something he’ll tackle when he gets some free time.

Boost issues or not, we think that the video below speaks for itself. The hat is certainly an attention getter, and we think it’s great – even if wearing a Tesla coil on your head is not necessarily the safest thing to do.

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