November
1997, Issue 88
From
the Bench:
Nonintrusive Interfacing - Using Kid Gloves
by
Jeff Bachiochi
Nobody
has ever accused Jeff of growing up, especially
his kids. Follow along as he unobtrusively updates
an already modernized classic toy.
Start
• Look,
But Don't Touch
• First
Breath •
Text
and Graphics Frames •
Sources
& PDF
Stairsteps
were a natural. Circles, on the other hand, were frustratingly
elusive. Good coordination was a must. Hours of intensive
creativity produced only a brief period of admiration.
And then, it was gone with shake.
Have
you guessed? You saw one on a previous cover of INK.
It's red with white knobs. One knob draws horizontally,
while the other draws vertically.
Yeah,
that's it--the Etch-A-Sketch from The Ohio Art Company.
You had one as a tyke, right?
The
simplicity was elegant. Instead of drawing on a surface,
the Etch starts by coating the surface with a reflective
material and then proceeds to remove the coating as
you draw.
As
the knobs move their appropriate axes, the wiper moves
at the intersection of the axes. The wiper dislodges
the coating from the inside of the top transparent surface
so it drops off the surface, producing a nonreflective
line.
The only drawback was no permanent
record of the masterpiece. And, then along came electronics.
Ohio Art jumped on the "batteries are better"
bandwagon and produced the Etch-A-Sketch Animator shown
in Photo 1.
The
Animator has an LCD screen of 30 high x 40 wide square
pixels. Each pixel is about one-tenth of an inch. Two
familiar knobs move the cursor (one square pixel) around
the screen.
I
felt right at home drawing stairstepped circles just
like I did when I was young. With square pixels, it's
impossible to draw perfect circles.
Eight
new pushbuttons adorn the electronic sketch pad. Three
buttons set the creating mode--move, draw, and erase.
With these, you move without affecting the pixels you
pass over, leave a trail of "on" pixels, or
leave a trail of "off" pixels using the x
and y direction knobs.
The
next three buttons--save, recall, and next--control
frames. A frame is where you place your finished picture
(you're allowed up to 12). The frame controls let you
store the active picture to the present frame number,
copy the last frame to the next frame, and move to the
next frame.
The
last two buttons are special effects. The reverse button
changes the state of all pixels (on to off and off to
on). The animate button enables you to play any of the
12 frames back in sequence. The sequence can be up to
96 frames in any order.
After
three minutes of nonuse, the Animator turns itself off.
As long as the batteries remain in the unit, all the
frames are stored. Changing the batteries erases all
the frames.
