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AVR Datalogger Zero

Intro

AVRDL0, or AVR Datalogger version 0, is essentially a practice project for me. It is mainly intended to help develop experience with technology useful for building data loggers, specifically sd card storage and ethernet connectivity. For maximum hackability, nearly all the components are through-hole versions and a third of the board is a soldered prototype area. Most of the interesting connections are available. For prototyping purposes there are also positions for an LMD18200 bridge, a barrel jack, and two SOIC-16 chips, all of which are ordinarily hard to solder to a 0.1" grid.

Despite being a prototype, the board is designed for low power operation. Most onboard systems are powered by a 3.3v switching regulator which can be shut down by the AVR, which itself is powered by a 3.3v linear regulator. In sleep mode with only its 32khz real-time clock operating the AVR consumes well below a milliamp of current.

The first (test) application of this is as a new controller for the lights and watering system for some plants.

board.gif

Eagle Cad design.

Software

There is a lot of free software available for AVR. For this board I've made use of:

FreeRTOS - a small realtime executive which provides basic multi-threading.
uIP - a small TCP/IP stack that uses minimal memory.
MMC/SD/SDHC card library - some code for working with FAT filesystems on SD memory cards.
Procyon AVRLib - various AVR libraries including ENC26J60 driver.

All of this is written in C and I use the free avr-gcc compiler to build it.