RFID Drink System Eliminates The Need For Change

April 4, 2011 by Mike Nathan 61 Comments

popcard_vending_machine

[Avatar-X] snagged a drink vending machine online a few years back, and has been selling drinks to his neighbors ever since. People are always asking him for change, and just the other day he was thirsty and out of change himself. He considered adding an override key so that he could snag free drinks whenever he pleased, but decided to go all out and built a cash card system instead.

He didn’t know how to interface with the machine’s logic board, so after poring over the service manual he consulted with a support rep from the company that manufactured it. Luckily, he was able to get enough information from them to start making some headway. With his friend’s assistance, he was able to figure out which pins on the Bill Validator Interface needed to be shorted in order to simulate the addition of funds.

Using an Arduino with an Ethernet shield, LCD display, and an RFID reader, he had his PopCARD system up and running in no time. Now all his neighbors have to do when they want a drink is swipe their card in front of the machine and hit a button to add funds from their account.

As you can see in the video below it works great, and we’re sure his neighbors are pleased with the improvements he has made.

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Propeller Lamp

March 30, 2011 by Kevin Dady 16 Comments

Wanting to replace a power hungry halogen lamp in the living room, [Jason Dorie] went out to design a Remote Controlled, Dimmable Led Lamp (pictures). The body of the lamp is a pretty interesting idea, sporting a couple waste baskets with a translucent HDPE skin as the lampshade and a PVC column for structure.

The column is wrapped in a spiral of 16 foot long led strips , and are wired so they can be controlled in groups. Light output is (estimated) at about the same as a 100-150 watt incandescent while only consuming 24 watts.

The lamp is controlled via a universal remote and features a TLC5940 driven by a Propeller, all sitting on a CNC machined PCB. With that much horsepower under a lamp you can expect that it will not just simply dim in and out, so join us after the break for a video to see how to turn on a lamp with style.

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CFL Breakdown

March 29, 2011 by Kevin Dady 26 Comments

Reader [Jay] was inspired by one of our earlier articles and started digging around the web for some more information, and found a handy web page with tear downs and schematics of popular compact florescent lamps.

Schematics are provided to 15 fairly common models including bigluz, isotronic, luxtek, maway, maxilux, polaris, brownie, Phillips, Ikea, Osram, and eurolight. Also, just in case you were ever interested in these little packages but did not want to open them due to sharp glass, mercury vapor, or phosphorus powders, photos are provided as well.

So if you need a few hundred extra volts to pack a little spark in your next project, need a 63rd way to cook your goose you should check this page out.

Keeping Beer Chilled From Keg To Tap

March 28, 2011 by Mike Nathan 21 Comments

beer_chiller

[Stan] was putting together his nano-brewery, and while waiting for his beer to finish fermenting, he decided to work on the storage portion of his project. He built a kegerator to store his forthcoming brews but realized that since it was about 10 feet away from his tap tower, the beer was becoming unacceptably warm and frothy in transit.

In commercial tap systems, a separate line of chilled propylene glycol is bundled with the beer lines, keeping it cool as it travels from keg to tap. [Stan] decided to replicate this setup, and after three different iterations, he nailed it.

His first two attempts involved keeping the cooling solution inside of the kegerator, but he found that either the pumps added too much heat to the solution, or that the kegerator was running at nearly a 100% duty cycle. Scrapping any sort of kegerator-based cooling, he decided to build a separate cooling unit with a dehumidifier he had sitting around. After fitting the unit into a cooler and filling it with solution, he found it to cool so well it turned the propylene glycol solution to slush!

Check out his site for more details on his cooling setup – if you are in the business of homebrew, you will be glad you did.

Open Source Wireless Mesh Networking Energy Meter

March 28, 2011 by Jesse Congdon 35 Comments

[Jay Kickliter] writes in to tell us about his open source energy/power meter. With his buddy [Frank Lynam] they designed a small device that crams into existing power boxes and uses and 8 core propeller (P8X32A) microcontroller to perform true RMS voltage and current measurements using a current transformer. [Frank] and [Jay] don’t stop there. The meter also features an xbee pro 900 MHZ to provide wireless (and even mesh networking) capabilities to the whole ordeal.

[Jay and Frank] estimate a total unit cost of around $80 (US) per prototype. With volume the price goes down by about half. With a larger number of units, and the magic of mesh networking, we could see cheaper xbee’s driving the cost down some. Check out the Google code page for details or the schematic (pdf) if you are interested.

So far the project is in the beta stages, and only features a single module sending data to a PC running an OS X Cocoa application. [Jay] is about to be otherwise occupied by the Merchant Marines and [Frank] the Navy, so they figured we could have a go at it for awhile.

We have seen other hardware used to monitor power consumption, but cramming this circuit into each power box is a neat idea.

[Frank] explains the whole project in the video after the jump.

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Smartphone Operated Garage Door Is Beginning Of Arduino Home Automation System

March 20, 2011 by Mike Szczys 15 Comments

[Tim] is showing off the first step in his home automation projected with this smart-phone garage door interface. In the video after the break you can see him open and close the garage door with the touch of a button. There’s also an open or closed indicator that he can check when away from home.

An Arduino takes care of a portion of the control for this project. Like the post we saw yesterday, he’s using PHP code on a webpage to manipulate the Arduino via its USB connection in order to open and close the door using a relay. The door status is also monitored by the Arduino and sent to the PC over the serial connection. The computer uses a Python script to monitor the incoming data and update a text file which is merged into the web interface using a PHP include. Future plans for the system include adding control for heating and air conditioning systems.

If you’re looking to do something like this but wirelessly here’s some advice on ditching the Arduino and using an XBee module instead.

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Building A Home Automation Mesh Network

March 19, 2011 by Mike Szczys 12 Comments

[Ian Harris] designed a bunch of home automation for his parents using X10 hardware. He was a bit disappointed by the failure rate of the modules and the overall performance of the system so he set out to replace it with his own hardware. Lucky for use he’s documented the journey in a four-part series about mesh networks.

The hardware seen above is his test rig. He’s using a couple of Sparkfun breakout boards to develop for nrf2401a RF transceiver chips. These could be used as slave modules, with a central command device, but due to the home’s architecture wireless signals don’t propagate well from one end of the house to the other. The solution is to build a mesh network that will allow each module to act as a network node, receiving and passing on messages until they arrive at the target device. He’s trying to do this with cheap hardware, selecting the PIC 16F88 which boasts 7 KB or program memory and 368 bytes of ram. In the end it doesn’t take much code to get this running, it’s the concepts that take some time and research before you’ll be comfortable working with them.

[Thanks Oakkar7]