Newsgroups: comp.robotics
Path: brunix!sgiblab!spool.mu.edu!howland.reston.ans.net!europa.eng.gtefsd.com!MathWorks.Com!news.kei.com!world!sje
From: sje@world.std.com (Steven J Edwards)
Subject: Stamp Kit experience
Message-ID: <Ctz9Fv.3Lz@world.std.com>
Organization: The World @ Software Tool & Die
Date: Wed, 3 Aug 1994 21:09:30 GMT
Lines: 40

I ordered and recieved a Stamp and a Stamp Development Kit from
Parallax last week; this is the US$40/Stamp plus US$100/dev kit
package.

I was pleasently surprised when the whole thing worked right out of
the box.  I loaded the development kit software onto an old 386SX
notebook, wrote a very simple program, and had it downloaded, running,
and tested in under five minutes.  Operation was verified by checking
the signals generated at the output pins by using an oscilloscope.

I did notice some minor crosstalk among the I/O pins where a spurious
ghost signal was detected on non-driven outputs.  However, the
ampiltude of the ghost was only a few tens of mV while the real signal
output was from zero to 5 V.  The Stamp was powered by a 9 V battery.

For future work, I need to first verify the following:

1) Ability to drive a 5 V, 250 ohm SPST reed relay from an output pin,
max two per Stamp.

2) Ability to read a 0.1uF/CdS (photoresistor) series circuit sensor
into an input pin; the resistance will vary from about 5 Kohm to 25
Kohm.

3) Ability to do the photoresistor sampling at a rate of 5 Hz or
better (I assume the CsD has a fast enough response time and that the
"pot" command will work properly).

4) Ability to to reliable serial I/O to the computer.

5) Ability to connect at least seven Stamps together with serial I/O
in a bus configuration.  I see in the application notes where three
can be so connected, but there is no explicit upper limit mentioned.

Essentially, I need to control a bunch of relays in a crossbar
configuration and to also be able to sample an LED array.  I would be
interested to hear from others regarding their experiences with
similar requirements.

-- Steven (sje@world.std.com)
