A Simple Method For Expanding Arduino IO Capacity

November 8, 2011 by Jeremy Cook 52 Comments

Although there are other ways to do this, [Rod] has decided to write up his method of using two Arduinos and the I2C protocol to expand an Arduino’s IO capacity. As seen in the picture above, you’ll sacrifice 2 analog pins, but if you happen to need IO and have an extra Arduino lying around, this could really help. [Rod] also notes that this method could be used with many Arduino’s in parallel if the situation called for it. The code for this simple hack is included as well, so be sure to check out his site if you want to try this idea.

Some other solutions for extra IO would be to buy an Arduino Mega with 54 digital IO pins or the Muxshield which gives you 48 IO (and is stackable for other shields). An advantage of using the two Arduinos, is that if they are needed to be split in the future for different projects, this could be done. It’s good to have options for your IO needs as every hack is different.

Check out the video after the break to see everything being hooked up.

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G-35 Christmas Lights Do Make A Great LED Matrix

November 7, 2011 by Mike Szczys 16 Comments

This fully-addressable RGB LED matrix was built by [John Graham-Cummings]. He didn’t start from scratch, but wisely repurposed a strand of GE Color Effect lights and built a pleasant looking case in which to mount the G-35 hardware.

We’ve seen this hardware used in a similar way before. Because each ‘bulb’ has its own microcontroller, color data is shifted in via a serial bus. Orient the modules in any pattern you choose and account for that layout in software.

Since the strings have 50 bulbs, [John] simply cut off the one on the end to form his 7×7 matrix with the remaining 49 units. A square of plywood with a grid of holes holds each in place. Cord mess is not a problem as the extra was cut out and the remainders were soldered together again. [John] uses an Arduino Pro to feed in the data, which you can see for yourself in the clip after the break.

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Hacking A “magic Wand” To Remotely Control Light Displays

November 7, 2011 by Mike Nathan 12 Comments

Hackaday reader [Kieran] volunteers at an outdoor haunted house attraction called the “Disenchanted Forest”. Attendees are lead through the haunted forest by a volunteer, who helps keep everyone on the predetermined trail. The trail is usually lit by small LED fixtures that the group constructed, but the organizers wanted to make the lights more interactive this time around.

A fellow organizer gave [Kieran] a [Harry Potter] Magic Candle, which allows him to light the toy with the wave of his IR-enabled wand. He was told to “make it do something cool”, so he took a closer look at it to determine how everything worked.

Using an Arduino clone and some borrowed IR code he was able to get the wand to work with the forest’s trail lighting, but there was a lot of lag between waving the wand and triggering the light. Taking a second stab at it, [Kieran] was able to replicate the IR protocol used by the toy, speeding things up and increasing the wand’s range considerably. Now, the tour guides can light and extinguish the trail lighting with a simple flick of the wrist.

Take a look at the video below to see how things worked out for [Kieran], and be sure to swing by his site for more details if you have the urge to modify your Magic Candle.

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Halloween Hacks: Motion Sensing Fog Machine

November 4, 2011 by Mike Nathan 6 Comments

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motion-sensing-fogger

[monkeysinacan] wanted to add a fog machine to his Halloween display, but he says that the cheaper consumer-grade models are pretty unruly beasts. He cites short duty cycles and tricky fog control as his two biggest gripes with these sorts of foggers. He decided make the fogging process a little more manageable, and modified his to only generate fog when someone was walking nearby.

One obvious concern with this sort of setup is the warm-up time required to get the device ready to produce fog. If it were to only turn on when someone walked by, [monkeysinacan] would miss his mark each and every time. To ensure that his machine was accurate, he rigged it so that the heat exchanger stayed powered on, triggering the fog juice pump as needed.

To do this, he used an ultrasonic sensor similar to, but cheaper than a Parallax Ping unit. Paired with an Arduino, the sensor triggers the fog machine’s pump for 20 seconds whenever anyone gets within 6 feet of it.

While he hasn’t posted video of the modified fogger at work, it sounds like a solid plan to us.

DIY Binary Alarm Clock Small Enough To Fit In Your Pocket

November 4, 2011 by Mike Nathan 22 Comments

[linux-dude] always wanted to have a binary clock, but he didn’t want to pay someone else to make it for him. Additionally, he was looking for a compact alarm clock he could take on the road, rather than relying on the one in his hotel room.

Inspired by other binary clock projects he has seen over the years, he set off to build his own, which he wanted to fit inside an Altoids tin. His binary clock uses an Arduino Duemilanove (which fits perfectly in the tin) to keep time and control the indicator LEDs. The LEDs are arranged in two rows as you would expect, representing hours and minutes. A small piezo speaker serves as the alarm buzzer, which should be sufficient to wake up most people, though something bigger might be required for heavy sleepers.

We didn’t see any sort of battery pack or power plug mentioned, so we’re not quite sure how [linux-dude] keeps his clock juiced up. Additionally, the lack of an real time clock is something we’re puzzled by. While the Arduino does have a clock function that can be used, an RTC might serve him better – then again if he’s gone for just a day or two at a time, a small amount of drift may not be an issue.

Beer Security System Keeps Freeloaders Out Of Your Stash

November 3, 2011 by Mike Nathan 29 Comments

The crew at the Milwaukee Hackerspace are pretty serious about their beer. They used to have a fridge filled with cans, available to all at the hackerspace, but they decided to beef things up and create a secured beer dispensing system.

Like many others we have seen, their kegerator is built into an old refrigerator, complete with a tap built into the door. To ensure that interlopers are kept from their precious brew, they have secured the refrigerator using an Arduino and RFID tags to grant access. They use the same RFID key fobs members carry to gain access to the space for tracking beer consumption, unlocking the tap whenever a valid tag is swiped past the sensor.

They are still in the midst of tweaking and revising the system, but it looks good so far. It’s a great way to keep uninvited guests from their beer stash, while giving them a way to track consumption at the same time. We’re looking forward to seeing more details and code once things are completely wrapped up.

[via BuildLounge]

Urine Territory Marking, Now For Humans!

November 2, 2011 by Jeremy Cook 14 Comments

Although Dogs and other animals love to mark their territory with urine, this technique has been generally ignored by human beings. Despair no more, fellow homo sapiens, we have now developed the ability to check-in on foursquare through your information stream. This device is descriptively called “Mark your Territory.”

Although this is not currently available to buy in stores (although apparently $10,000 will get you one built), [Instructables] user [blorgggggg] has furnished directions on building your own. The system is powered by an Arduino and an Android phone. The urine tags have both a pointed end for sticking in grass and the like, and a sticky back to be used in a “more urban settings.”

The video after the break gives quite a bit of background trying to justify such a system in terms of communicating in the physical world, animals, et cetera, but it’s doubtful that this excuse will get you out of a public urination charge. You’ve been warned.

[youtube http://www.youtube.com/watch?v=rRdfeb7vDWg&w=470&h=315%5D