Project idea - requirements?

Hi everyone,

I have a project idea which I would like to use an Arduino to run. However, this would be my first time using an Arduino and I'm not really sure of the capabilities of the Arduino, and what external parts would be needed. I am hoping some people here can direct me to some good parts to use and correct any misunderstandings I have developed. I have programmed microcontrollers and FPGAs before, so hopefully the actual implementation won't be too terribly difficult to write. Here is the concept:

The Arduino will receive temperature (and ideally, humidity if not cost prohibitive) data. I assume that a simple thermistor would be fine for this, though I saw a somewhat expensive therm+humidity sensor at sparkfun. It will poll the temperature data periodically and if it is too hot, it will turn off a heat lamp (USA 110V AC) - and likewise turn it on when it is too cold. From reading, I understand a solid-state relay would be good for this. It will also keep track of time, and turn another lamp on and off on a 12-hour cycle. I don't know whether a real time clock chip/module would be needed here or whether I can just rely on the clock of the Arduino. Finally, I would like to be able to view the current temperature and lamp state over the Internet. The expensive way to do this seems to be via an Xport device. I was wondering if instead, I could use my PC and some scripting language to talk to the Arduino over its USB connection, send the request for current state information, and then read back the info from the Arduino and display it. It runs an apache web server already, but it is running Windows and I have read that while sending data is not a problem, receiving (USB) serial port data in Windows may not work.

Thanks in advance for any tips/help/ideas!

--Brandon

Hi Brandon, that sounds like a good project and well within the capabilities of for the Arduino.

You should have no problem sending and receiving data from the PC over the USB link. There is an issue with the current implementation of software serial but that shouldn't affect you because USB uses the hardware serial port.

If the PC is usually connected to the Arduino then you could get the time from there pc so you don't need worry about connecting an RTC to the Arduino.

Thanks for the input :) It sounds like a pretty reasonable idea. I wanted to depend as little on the PC as possible, but at least for now I can use the PC clock, and expand that functionality onto the Arduino later if I decide to.

Still wondering if anyone has any tips, recommendations, or howtos for sensing temperature/humidity and for controlling AC power.

--Brandon