What product do I need?

JacobK

I've spent a bunch of time on the Parallax site trying to figure out what product I need to buy given my project's feature set. But I can't figure it out. Perhaps someone out there can help me.

My project needs to:
Run standalone in a box outside powered by a 9V (or other) battery.
Run a time-based program.
Output:
The program needs to be able to play a sound file from an attached removable storage device. Ideally, I'd plug in a usb fob, and the program could read and play the files on it.
Send the audio out the analog port (I'd hook up an amp and speaker).
Power a tiny motor
Possibly turn a fan on and off to cool the board?
Input:
Get input values from a photovoltaic cell, so my program could do things starting when the sun comes up.
Possibly know when the battery starts to get low?

I'm a newbie, but perhaps someone knows off-hand what product I need to buy to do this.

Many thanks,
Jacob

Mike Green

If you particularly want to use a Stamp, you would need some external devices to do some of the work. In particular, a VMusic2 from Vinculum would be able to play MP3 tracks from a USB Flash Drive (www.vinculum.com/prd_vmusic1.html). If you want accurate timekeeping, some kind of external clock chip would be important like a Dallas DS1302 (datasheets.maxim-ic.com/en/ds/DS1302.pdf). Parallax has plenty of sample code using a Stamp to interface to this.

A Stamp would have no problem controlling a small motor and would not need a fan for cooling. It could easily measure the resistance of a photoresistor and there are plenty of examples for doing that. The small motor would require the use of a simple switching transistor. www.emesystems.com has some discussion (follow the link to "app-notes") on measuring the battery voltage using a Stamp.

I would not try to use a 9V battery. It has very little capacity. A 5-cell NiMH rechargable battery pack (2300 to 2500mAh) would be much better. You might even be able to use a small solar panel to keep it charged.

JacobK

Wow, thanks Mike! That's a lot of great info. Now I need to sort through it! I may be biting off more than I can chew.

Mike Green

First get familiar with the resources available from Parallax. Browse the Resources tab off the main website page. The Nuts and Volts Columns are particularly useful as well as the Stamps in Class tutorials off the Downloads page (from the Resources tab). For the Stamp, get a copy of the Basic Stamp Syntax and Reference Manual and the "What's a Microcontroller?" tutorial.