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Issue
99, October 1998
X-Y Graphing Data
Logger
by
Alberto Ricci Bitti
Start
• Machine
Muscle
• Using
Componentware
• Low-Power
Guys
• Flash
Risc Glue
• The Graphic
Engine
• Casio
Protocol
• Main
Code
• Inside
The Box
• Setting
up the Casio
• First
Graph
• Modeling
The Data
• Broader
Vision
• Software,
References & Sources
BROADER
VISION
Since this design was announced
in INK 95, I’ve received lots of E-mail from
interested readers. Each one had a different vision of
what this little design can be used for—from tracking
the accuracy of a GPS-locked PLL and plotting weather
data, to shoving a waveform from an instrument and monitoring
a central heater’s operation, or counting people
coming in a door.
The number of possible applications
exploded. Built-in display and the capability of being
programmed, combined with very low cost, are the key factors.
I encourage you to expand
the capabilities of the data logger. The code is fully
commented, and the PIC program memory is only half full.
I do have a couple suggestions.
As a first step, try adding a pulse-counter mode. There
are lots of things worth counting, and many sensors (e.g.,
Steve and Jeff’s lightning sensor [INK 90])
have pulse outputs.
Secondly, drive outputs by
implementing the Casio command Send(X) to make the interface
bidirectional. The Casio is slow but powerful enough to
read in the input, make some computations, and send output
to the outside world. In this way, it would migrate from
the world of monitoring and displaying events to the broader
world of (pocket) computer control.
Alberto Ricci Bitti is
a software designer at Eptar, an industrial-controller
firm. He has written software for systems such as meteorological
equipment, specialized TV sets, professional satellite
devices, industrial machinery controllers, and energy-management
devices. You may reach Alberto at a.riccibitti@ra.nettuno.it.
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