Make Your Own Mindstorm Sensors

August 6, 2010 by Mike Szczys 16 Comments

[Stewart Allen] acquired a Mindstorm kit about a month ago and he’s already building his own sensors for it. He wanted a more accurate range finder with a narrower measurement field than the stock sensor. Mindstorm has the option to communicate with sensors via an I2C bus. [Stewart] set up an ATtiny45 to act as a the slave on the bus, facilitating the analog measurement of the distance voltage by using and lookup table, and handling the data transfer with the NXT brick. His testing setup is pictured above, with an AVR Dragon for programming the tiny45 and a Bus Pirate for sniffing the I2C data during the development process. The sensor, looking great on a professionally made PCB he ordered, requires a simple driver that [Stewart] hammered out for use with leJOS, the alternative Mindstorm firmware we’ve seen before.

RGB VU Meter

August 5, 2010 by Mike Szczys 18 Comments

[Simon Inns] turned out this VU meter with a 16 RGB LEDs. He’s using three 16-bit TLC5940NTG LED drivers for the project. They’re not cheap chips but they do a great job. If you were looking to save on parts [Simon] found there’s more than enough brightness and any loss due to multiplexing would not be a problem. The device connects to a computer via USB thanks to the PIC 18F2550 which he’s used in his past VU meter projects. One of the design choices he made was to use a switching power supply. The LM2576 (datasheet) has no problem sourcing 3A at 5V and in addition to two electrolytic capacitors which are commonly used with linear regulators, you just need to add a diode and an inductor.

The meter offers several different configurations which are set on the PC side of things. These include the colors that are used and if the entire bars is used as one meter or split into sections to display both audio channels. Check it out after the break.

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Teensy Credit Card Reader

July 24, 2010 by Mike Szczys 26 Comments

Here’s a hack that makes business sense. [PT] recalls last year’s HOPE conference when their booth was using a virtual credit card terminal for purchases that required manual entry of card information. This year they’ll have the same virtual terminal but this magnetic stripe reader will fill it out automatically.

A magstripe reader (reading only, no funny business here) from Mouser grabs data from the card. A Teensy microcontroller board, which identifies itself as a USB keyboard, automatically fills out the virtual terminal from the parsed data. The real question, are his customers comfortable sliding their plastic through a hacked reader?

Hands-free Input

July 20, 2010 by Mike Szczys 8 Comments

This is a concept input device that [Tech B] built for disabled users. The device uses an accelerometer along with a piezo sensor (right click) and a push button (left click) to function as a mouse. The Arduino that resides in a breadboard on the side of the hat communicates with the computer over a serial connection, using PySerial to translate the microcontroller data into cursor commands with the power and ease of the Python programming language.

During development [Tech B] made a proof-of-concept video using a Basic Stamp which you can watch after the break. He found that this input device was less complicated, more accurate, and much less resource intensive than his webcam IR tracking system.

OpenWRT On A Seagate FreeAgent Dockstar

July 17, 2010 by Mike Szczys 50 Comments

The Seagate FreeAgent Dockstar aims to make all of your stuff available online. It serves that purpose but sometimes you just want more options for controlling your hardware and running some scripts. [Eric Cooper] put together a guide for installing OpenWRT on the Dockstar by building your own kernel and loading it onto the internal storage. Once you have a kernel that will play nicely with the hardware, you can install it by tunneling in through SSH; the same method you would use if you wanted to run Linux on this hardware. If you have problems along the way, [Eric’s] also included a guide for cracking the Dockstar open and connecting a serial cable.

Connecting A Nokia 3310 LCD Using An AVR

July 6, 2010 by Caleb Kraft 7 Comments

In this instructible, [wkter] takes us through the process of running a Nokia 3310 LCD display using an ATmega8. This instructible isn’t a beginners project as he assumes you already have a strong understanding of how to work with these components and their programming languages. He is very thorough with information though, providing datasheets, pinout diagrams, and source code. Once you get this down, you could go a little further and make Conway’s game of life.

Microcontrollers Access The Web

July 1, 2010 by Caleb Kraft 10 Comments

[youtube=http://www.youtube.com/watch?v=ExoJDxBGEBU]

[Kenneth Finnegan] is back with another video showing some cool stuff he’s doing to connect his microcontrollers to the internet. Usually, we see this done with a prebuilt module like an iobridge. [Kenneth] is using a Microchip ENC28j60 module for the communication and he’s managed to stuff it all onto a tiny Electroboards piece. [Kenneth] is starting to become a regular around here.

[via HackedGadgets]