I needed a gadget to display a temperature reading over the Internet. Sure, a general purpose PC could probably be rigged to do this, but I had some parts laying around so I decided to build something.
The project uses the Rabbit Semiconductor RCM2200 module as it’s core. The RCM2200 is connected to a Maxim DS1620 digital thermometer.
Total time to breadboard and write software was about 1.5 hours. Time to etch and assemble the PC-board was about another 1.5 hours. Here’s a picture of the completed project:
The RCM2200 is the greenish module in the upper right corner. It has a built in ethernet jack, CPU, flash memory, etc. To the left of the RCM2200 is the DS1620. Below the DS1620 is a 7805 5V voltage regulator. The only problem with the layout is at high input voltages, the regulator produces a great deal of heat, which could effect the reading of the DS1620. I use an input voltage of 7.5V, which does not cause any problems.
Below is a schematic of the circuit:
There’s a multitude of jumpers (RESET, INPUT1, INPUT2, VBATSEL, OUT2, and VOUT) that are purely optional.