Tell me what I need


I'm new to Arduino and I could use some help figuring out what to buy. I have a simple project where I need to log the date and time every time a button is pushed. Ideally, I'd like to create a text file on a USB stick where a new line is written each time the button is pushed. It would look something like:

20101214_150522 20101214_150548 20101214_150633

if the button were pushed on Dec. 12, 2010 at 3:05:22 pm, 3:05:48 pm, and 3:06:33 pm. Exactly what hardware do I need to buy to make this happen? I have plenty of resistors, buttons, and simple circuit components on hand. The only real constraints are that I'd like to keep this low-cost and low-power.

Thanks in advance!

What you need is to Google "arduino real time clock" and "arduino data logger".

You might want to look at the Seeeduino Stalker. That would fir your bill nicely in one package.


Hmmm…the Seeeduino Stalker looks interesting. Would I need the Arduino in addition to the Seeeduino Stalker? And would I need something to connect it to the USB stick or SD card?

It looks like another route would be the Data Logging Shield for Arduino ($20). Add that to the Arduino Uno ($35) for a total cost of $55. Is this the simplest, most cost-effective option?

Whoa, Richard, that looks great! I think I'll give the OpenLog a shot.

To make sure I understand this correctly, I can edit a config.txt file directly on the SDHC card from a computer and I will never need to connect the OpenLog to my computer? And I do not need an Arduino at any point in this project? In terms of hardware, I am under the impression that I can hook up the OpenLog to a power source, connect a simple push-button circuit to the input, and the OpenLog will write a timestamp when the button is pressed? Very cool!

How accurate is the built-in clock? I'd like to build a few of these and place them around the house. That way I can log my activities (e.g. opening the fridge) over the course of a few months.

Richard, forgive my ignorance, but how do I go about editing the code for the OpenLog board? Does the OpenLog board read its code from a file on the SDHC card, or do I need to interface with the OpenLog board itself in some other way? I have plenty of experience with writing code, and plenty of experience building circuits, but this is my first foray into the world of microcontrollers--I need a little help getting over the first hump.