Data Logging - There are three pieces in the data logging puzzle, the first is the sensor and its associated programming to produce a piece of data. The second and third pieces are an accurate time base and a way to record or log the data. These last two will be addressed here. While these solutions were selected or designed with Freeduino/Arduino(r) based hardware in mind, they work equally well with any processor supporting I2C in software, firmware or hardware, including, but certainly not limited to PICs, Parallax Basic Stamps family and Propeller, RevEd PICAXE, and so on.

Wulfden I2C MemStamp board - This board is a simple postage stamp sized board that holds a single 24LCxxx or 24AAxxx series serial EEPROM chip. It will take any chip in the series up to and including the 24LC512/24AA512 which holds 512K bits (64Kbytes). The chip is addressed at $50 (address 0) and has a three position jumper for he Write protect line;

• Write Enabled - WP to Vss (jumper to left)
• Write Protected - WP to Vdd (jumper to right)
• External Control - WP to board pin 2 (jumper in center)

The I2C MemStamp comes as a basic kit, pcb, 8 pin 3M socket, headers and jumper. It can also be purchased with 512 Kbit (64KB) serial EEPROM chip. Assembly is stright forward. The schematic is available

Wulfden I2C RTC/EEPROM Board - has a DS1307 RTC with battery backup, provisiosn for up to two(2) 24LCxxx serial EEPROM chips and four positions of scaling resistor sets hooked to available analog ports. This I2C board was design specifically to plug directly into a Modern Devices BBB (Wulfden Freeduino Kit) or any of the 168/328 based Arduino(tm) boards. One of the pin header layouts is sufficicently generic that it can readily interfaced to any processor with I2C support. The Wulfden I2C Board comes as a basic kit with all the RTC componenets and the EEPROM sockets, or as a complete kit with two(2) 24LC512 chips.

• DS1307 chip
• 32KHz watch crystal
• 3 3M 8 pin DIP sockets
• new Maxel CR2032 battery and holder
• 2 4.7K pullup resistors
• complete assortment of connecting headers
• 8 1% precision resistors for analog voltage scaling. The following values supplied produce these scales to 0-5 volts
  • 10K/10K for 0-10 volts
  • 10K/4.53K for 0 to 16.03 volts
  • 10K/4.53K for 0 to 16.03 volts
  • 22.6K/4.53K for 0 to 29.94 volts
• for other ranges you will have to supply your own
• the serial EEPROM chips are addressed as $50 and $51 (addresses 0 and 1)
• Assembly and use is straight forward. Schematics. manual, and sample code coming soon.
• serial EEPROM chips are not part of the basic kit. We stock 24LC512 (64KB) chips and can supply them