LCD Backpack: From Arduino Board To Homemade Pcb

October 17, 2011 by 7 Comments

[Kaushlesh Chandel] prototyped a few projects on his Arduino that use an HD44780 Character LCD. Wanting to keep these projects in one piece, but not sacrifice his Arduino board, so he etched his own LCD backpack that is Arduino compatible. If you’ve never made it past the Arduino board to build a module that only uses the parts you need for a project, this is a great source of inspiration for you to give it a try.

The design that [Kaushlesh] drew up is quite simple. It connects directly to the single in-line header of the character LCD. It looks like he’s using the 4-bit mode for addressing that display, which leaves you with quite a few pins (both digital and analog) to work with in the future. The important components rolled into his design are the chip itself, an ATmega8/168/328, the crystal to make sure it is running at the correct speed for Arduino timing, and a trimpot for adjusting the contrast on the display. The final feature you’ll want to be sure to include in your own design is a pin header for programming the chip via an FTDI cable.

Never etched your own PCB before? Give our PCB fab tutorial a try.

PopCARD Vending Machine Enhancement Gets Upgraded

October 17, 2011 by 18 Comments

[Alex] wrote in to let us know he just completed a pretty major upgrade to his PopCARD RFID vending machine system. You may remember that earlier this year he added an Arduino based RFID reader to a soda machine so that thirsty patrons could pay with plastic instead of cold hard cash. That system worked, but at the beginning of the video after the break [Alex] goes over some of its flaws. There was a button to add cash from the card to the machine in $1 increments, rather than the system just knowing how much to charge you. Also, if you accidentally selected something that was out of stock you were out of luck and were charged anyway.

The new system does away with the button, and knows what product is sold out. The control hardware was upgraded to an Arduino mega to gain extra I/O pins. The device now sits in between the machine’s buttons and its own controller. When cash is used, the Arduino sits passively and lets the machine do its thing. But when a card is scanned, it takes over control of the buttons, sensing your selection, then simulating coin and button presses to vend accordingly. The new setup also uses an Ethernet shield which allows [Alex] to tell what items are running low without being at the machine itself.

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Tactile 4-bit Maze

October 17, 2011 by 17 Comments

[Oskar] has been making puzzles for some time now. In 2000, he made a small electromechanical 4-bit maze that’s really fun to play. Lately though, he’s been working on an improved version that could be the beginnings of a commercial product.

The earlier electromechanical maze (you can play it in an applet on that page) is just a microcontroller hooked up to electromagnets and switches. To complete the maze, find the patterns of bits that move everything from 0 to 1. It’s a little bit like the Fox Chicken Grain puzzle, only a bit more complicated.

[Oskar]’s latest version uses motorized faders to represent the 0 and 1 states of the bits. The same logic in the electromechanical version is in the newest version. An Ardunio takes care of the motor control and game logic.

As a tiny logic game toy, it’s a great idea; everybody needs to get some hands-on action with Karnaugh maps sometime in their life. Check out the video below for the demo of the 4-bit maze in action.

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Making Luminol From Household Chemicals

October 17, 2011 by 45 Comments

What to make your own chemiluminescent material? Check out this process that uses common household goods to synthesize luminol. You’ll need some lab equipment, and [NurdRage] mentions some precautions to take as luminol is not itself toxic, but some of the fumes and intermediary chemicals found during the process are.

Start by cutting up some vinyl gloves and boiling them with some rubbing alcohol to extract diethyl hexyl phthalate. After filtering, that gets boiled with water and some drain cleaner. The goal here is to continue the process until you have pure phthalic anhydride. Almost done? Not even getting started. This is a very complicated process, but fascinating to watch. After the break you’ll find the full video, or a five-minute abridged version for those that just want a taste of this experiment.

When we looked at the quantum dot manufacturing process a couple of days ago we asked for more chemistry hacks. This is exactly what we were talking about and are thankful that [Rob] sent in the tip. Keep them coming!

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How To Develop For STM32 Discovery Boards Using Linux

October 17, 2011 by 50 Comments

Some hard work has gone into making it possible to develop for the STM32 Discovery board using a Linux system. The board boasts an ARM Cortex-M3 processor, which can be programmed via the mini-USB port on the side. But the company only supports development through their IDE’s which don’t run natively on Linux. The stlink project aims to solve this, providing a toolchain, and making it possible to flash the microcontroller via the USB connection.

The github project linked above also includes a tutorial to get you started (pdf). In addition to a walk through on compiling the software packages, it includes a simple blink program that you can use to test out your hardware. GDB, the familiar open-source debugger, is used to flash the chip. This is a bare-bones tutorial so if you end up posting about your experiences using this toolchain with the Discovery boards we’d love to hear about it.

[Thanks Texane]

Modding An Inkjet For PCB Production

October 17, 2011 by 49 Comments

Like all of us, [Ryan] is tired of waiting for board production houses. To reduce some of that turnaround time, he modded an Epson inkjet into a PCB printer. The Instructable of his build is extremely thorough and it looks like he’s getting some quality boards out of his project

The build started off by disassembling an Epson C86 printer he had lying around the house. Going with an Epson printer is important – Epsons have a piezo print head accepts ink that would clog other printers. After tearing all the plastic off his printer, [Ryan] set to work raising the printer (or lowering the bed, whatever) and was off to the races.

The cartridges were filled with etch-resistant yellow ink and a piece of copper clad put onto the printer. After printing, [Ryan] etched his board in ferric chloride. Sadly, he’s getting small pinholes in his traces where a bit of the ink was eaten during etching. He’s tried HCl and Peroxide, but those turn his boards into green junk.

If you’ve got any tips to help [Ryan] out, leave them in the comments. Before that, check out the printing demo [Ryan] put up.

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The “Effervo” Kinect Particle Effect Machine

October 17, 2011 by 10 Comments

Here’s a new hack for the Xbox Kinect called “Effervo”. It’s a really cool effect built using Openframeworks. The Kinect is setup in front of the user and the projector puts an image in front of the user’s screen. Three dimensional data about the person and his or her movements is captured using Microsoft’s sensor. As it is described, the Effervo program “uses simple iterative rules to govern its movement and gives the impression of swarm like behavior.” This may not be a “Haloween Hack”, but we could definitely see something similar used in a haunted house. Maybe it could use blood droplets instead of particles?

Maybe this hack will inspire other people to follow in [Jayson’s] footsteps. He describes himself as a “programmer turned artist.” We’d like to think that all engineering and programming work is a form of art, but the video of this piece in action after the break is especially eye-catching.

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