Simpson's Did It!

While browsing the Maxim website I came across a surprise. They have a series of single chip (iButton packaging to be exact) that contain a temperature sensor, EEPROM memory, Real-time clock, serial protocol, etc. The DS1922L,DS1922T Temperature Logger iButton with 8kB Datalog Memory. It's everything I've been wanting to create with my Temperature Sensor/Datalogger project, but better, stronger, faster and smaller.

I should not have been surprised by it's existance. Because logging a temperature, over a long period of time, is such an obvious need. Being so obvious was a major reason I considered the project in the first place. But finding the entire circuit done much better in a rugged package depressed me for part of the day. I definately need to develop a thicker skin if I'm going to be working with such circuits for a living.

The DS1922 series is impressive. However I checked all the usual sources; Jameco, Digi-Key and Mouser. None of them carried the chip. Maxim gives the prices as $49US @ 1 unit, or $28US @ 1000+ units. That is a bit pricy.

I will take a closer look at it. I'm not familiar with iButton or the 1-Wire protocol. I still have not thought of a good way to get the data out of the EEPROM in my version, so I need to keep my options open.

I need to remember the entire point of this exercise was not to just develop a datalogger, but to learn by doing. Using an all-in-one, pre-developed system isn't going to help me learn.