This mini web server is slightly smaller than a business card. There are a lot of tiny one-board servers out there, but this is probably the smallest you can etch and solder at home. Unlike many embedded web servers, files are stored on a PC-readable SD card, not in a difficult-to-write EEPROM. Read on for the web server design, or catch up on PIC 24F basics in the previous article: Web server on a business card (part 1).
Continue reading “How-To: Web Server On A Business Card (Part 2)”
[youtube=http://www.youtube.com/watch?v=g_hiz-Kx0kM]
[jay] reminded us of this old video of solenoids banging rhythms on furniture and household objects. There’s no schematic, but in the video it looks like an Arduino drives a bunch of solenoids through relays. The PC interface is run on Pure Data, an open source programming environment for audio, video, and graphic processing. Thanks [Jay].
[youtube=http://www.youtube.com/watch?v=jYVgXYtxk4E]
[Perry’s] awesome AcceLED Pong project gives new life to a classic game by adding acceleration-based control. The pong paddles are moved by tilting the circuit left or right. Motion is measured by an ADXL203 dual axis accelerometer, and an ATMEGA32 microcontroller converts acceleration into ball and paddle movement. The game display is a three-color SparkFun 8×8 LED matrix with serial interface.
[Perry] also used a similar setup to make a USB LED spectrum analyzer fed by the Linux XMMS media player.
Every project needs a power supply. As 3.3volt logic replaces 5volt systems, we’re reaching for the LM317 adjustable voltage regulator, rather than the classic 7805. We’ve found four different hobbyist-friendly packages for different situations.
A simple voltage divider (R1,R2) sets the LM317 output between 1.25volts and 37volts; use this handy LM317 calculator to find resistor values. The regulator does its best to maintain 1.25volts on the adjust pin (ADJ), and converts any excess voltage to heat. Not all packages are the same. Choose a part that can supply enough current for your project, but make sure the package has sufficient heat dissipation properties to burn off the difference between the input and output voltages.
Continue reading “Parts: LM317 Adjustable Voltage Regulator”
Yesterday we linked to an OCZ Neural Acutator Interface teardown. Several in the comments wanted to know more about the sensor electrodes. Check out the OpenEEG project and OpenEEG mailing list for information on sensing, amplifying, and recording brain activity (EEG). The OpenEEG project maintains an open source Simple ModularEEG design. Two other open source variants of the ModularEEG are the MonolithEEG and [Joshua Wojnas’] Programmable Chip EEG BCI. All three projects use Atmel microcontrollers, with designs in Cadsoft Eagle.
Brain activity is measured using passive or active electrodes. Passive electrodes require a conductive paste to make proper contact with the skin (examples: 1, 2). Active EEG sensors don’t need conductive goop because they have an amplifier directly on the electrode (examples: 1, 2, 3).
[via anonymous reader, comments]
For years, Microchip PIC microcontrollers dominated; PIC16F84 hacks and projects are everywhere. The 8-bit 16F and 18F lines are supported by several coding environments and easy-to-build serial port programmers. Microchip’s 16-bit PIC24F is cheaper, faster, and easier to work with, but largely absent from hacks and projects.
We recently used a Microchip PIC24F microcontroller in a mini web server project, but didn’t find many introductory references to link to. In this article we’ll cover some PIC 24F basics: support circuitry and programming options. We’ll also talk about our favorite features, and how we figured them out. Our next article will outline a web server on a business card based on the PIC 24F.
Continue reading “How-To: Web Server On A Business Card (Part 1)”
m8ta fun did an extensive teardown of OCZ’s Neural Impulse Actuator (NIA). OCZ’s computer/mind interface is actually a fairly straight forward design. An analog front-end cleans and amplifies the ‘neural’ signal with a few op-amps before feeding it to a 24 bit analog to digital converter (ADC). A USB enabled PIC microcontroller reads the 24bit parallel ADC output through a common 7400 series parallel to serial adapter IC. The device has an ICSP programing header (top right), though it’s not yet clear if the PIC can be read or written.
[Thanks, joeyo]
