Arduino Temperature Datalogger

grabcad

If you've ever wondered how many K type temperature probe interfaces you can comfortably fit onto an Arduino Mega2560 or Due, I have the answer... 42.This is based on the MAX31855 chip that uses an SPI interface. There is SD card support on the board, so all can be done with the one interface, once the chip selects are mapped.The cutout at the end is for the type B connector on the Mega 2560, which on one of mine sits just too tall to seat the pcb fully.I've no idea what the max rate this will be able to poll and record will be. I expect it should operate the SPI bus at or above 100kHz, and hopefully it will cope with 1MHz. It's 32bits per read per chip, so a complete poll is 168 bytes. Even allowing for a 2048 byte sized block, there should be enough ram to load a block at a time.I have assumed that timekeeping will take place on the arduino, and have not included an RTC.