What is the best Stamp for data collection?

Michael3079

I am beginning a new project in which I believe a stamp would be the right means to implement. I've been experiementing with the BS2P24 to get familiar with the capability of the stamp and PBasic.

Some requirements:
··· Must be battery driven
··· Data collection to either SD or jump-drive·
··· Manage up to 10 external sensors with time-stamp
··· Lcd display with keyppad


I'm conerned·about the limited variable space on the BS2P. I'm running out of variable space with·a DS1302 Clock, a DS1620 temp sensor, and·a datalogger connected at this point. I will need to add several sensors before I'm done.

Is there a better stamp for this type of application. I've been reviewing specs on the Javelin and Propeller but I'm not sure if I will have similar problems as I begin to add sensors.

Thanks for any sugestions.

Mike Green

A Propeller would be a good choice for this sort of project. It has the ability to slow itself down to save power when speed isn't needed. It has plenty of variable space. It can handle all sorts of sensors including I2C and SPI, and it doesn't need the datalogger since it can connect directly to an SD card and handle PC compatible files. There's existing library code for a lot of different sensors including the DS1302 and DS1620. The Propeller can do its own analog to digital conversion using only 2 I/O pins / 2 resistors / 2 capacitors per ADC. You can get a better quality ADC with more features using a separate device, but the built-in capability is pretty good.

Disadvantages ... 1) It's different from the BS2 Stamps 2) It uses 3.3V logic. It can be connected to 5V logic devices, but you need some kind of interface, usually as simple as a resistor. There's a long "sticky" thread in the Propeller forum about signal interfacing. 3) The current SD card routines do not handle subdirectories or long file names.

Chris Savage

Some former customers of mine have been amazed at the things I have made a BASIC Stamp do in a commercial application. I don’t know how many times I have seen someone reach the point where they believed they exceeded the capabilities of the BASIC Stamp only to have a minimalist like myself make the application work, often with additional overhead.

That said, you may very well need something more. But I wouldn’t rule out a BASIC Stamp until you have really gone through your specifications and laid it all out. Then we can help you evaluate whether the BASIC Stamp could work. I have built several full-featured alarm systems around the BS2P40. Granted, my home system has an additional BS2, but that is in the remote keypad system. I always muse that with a Propeller I could turn the system into more of a Home Controller. The alarm system would only constitute a small portion of the system at that point.

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Chris Savage
Parallax Engineering