Arduino datalogging accelerometer with µ-SD storage
Arduino » Arduino Pro mini
The Arduino Pro Mini is a microcontroller board based on the Atmel ATmega168 (datasheet). It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, an on-board resonator, a reset button, and holes for mounting pin headers. A six pin header can be connected to an FTDI cable or Sparkfun breakout board to provide USB power and communication to the board.
The Arduino Pro Mini is intended for semi-permanent installation in objects or exhibitions. The board comes without pre-mounted headers, allowing the use of various types of connectors or direct soldering of wires. The pin layout is compatible with the Arduino Mini.
There are two version of the Pro Mini. One runs at 3.3V and 8 MHz, the other at 5V and 16 MHz.
Arduino Pro mini Schematic Diagram
Arduino datalogging accelerometer with µ-SD storage. Schematic
The code is highly configurable: it can save raw A/D values or converted values, it allows software-defined gain, it can collect for a set time or until user input, and of course the collection interval is user-defined. It also includes a "DEBUG" mode, in which it tells the serial line everything that's happening. It can collect multiple data files (up to 100) per card, and will tell you about any errors it encounters.
All this in a small enough program to fit on an ATMega168! The data collection rate is not as high as I'd like on this 8MHz chip, and the sync() calls to the µSD card cause missed data intervals when the sample period is below 100ms, but for slower data-collection situations it works great. (Does anyone make a 32MHz 3.3V Arduino? That would be nice, here...)
Now to go do some physics with it
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