30 Silicon chip Australia’s electronics magazine siliconchip.com.au1911118419111184GNDRESET3459101416MICROMITE
LCD BACKPACKMICROMITE
LCD BACKPACK17182122242526CON3+3.3V+5V5VTXRX()CONNECTIONS TO LCD GNDC+CON3CON120191kW19111184 RevCFlipdot Display Driver PCB12VGND12VGND5V^GND DLT CKEN5V^GND DLTCK EN33Fm1000 mFCOCON4N4CON2
CON2CON5CON6CON7CON8TO 12V POWER
SUPPLYÓSC 20 1 9
Fig.8: a microcontroller with 3.3V I/O can also control the Flip-dot Display directly, such as the Micromite shown here.
This is the recommended wiring, which allows you to use our test and sample programs without having to modify them.
(2.54mm) apart, so a nine-pin header
can be fitted for both, and that is what
we’ve done. It can be broken or cut off
a longer header strip if necessary. Sol-
der this to the holes on the left-hand
side of the PCB.
For the first board, which will be
wired back to the controlling device
(Arduino, Micromite etc) it’s best to
use female header(s) for CON1 and
CON3, to allow male-to-male jumper
wires to be used.
But for subsequent boards in a mul-
ti-character display, you’re better off
using a male pin header for CON1 and
CON3 instead. This can then be sol-
dered directly to the CON2/CON4 po-
sitions on the adjacent board, which
holds the two together and allows the
PCBs to butt right up to each other,
thanks to the two shallow cut-outs on
the edges of the board, into which the
header’s plastic block slots.
Another option would be to fit a fe-
male header (socket) for CON2/CON4
on one board, and a male pin header
for CON1/CON3 on the next board, and
plug them together. This would make
it easier to disconnect the boards later
if necessary, but they would then have
a gap between them. And you would
need to come up with a way to hold
them together, since the socket won’t
provide enough friction.CON2 and CON4 are not needed for
a single display. You can leave them
off at this point, and fit something later
after you have tested the unit, if you
decide to combine it with additional
display boards.Final assembly
Now that the glue and paint on the
pixel flaps has cured, these can be fit-
ted to the coil PCB’s frames. But first,
they need to be removed from the
PCB panel.
The best way to do this is to care-
fully cut the panel into smaller pieces
using a sharp pair of side-cutters. Take
care that the PCB material is quite brit-
tle, and the cut pieces may tend to fly
off. Aim away from the body, and use
eye protection. Fig.6 shows the recom-
mended cutting locations.
Now, without using any tools, break
the flaps by hand from the panel along
the mouse-bites. We found that the
rough edges were generally not a prob-
lem, but they can be filed back a small
amount (one or two passes only) with
a fine file. Again, beware of breathing
the dust from the PCB.
A good test to check that the pixels
are all magnetically aligned correctly
is to allow them to attract each other
into a single stack. If all the flaps show
the same colours on the same side,then they are aligned magnetically.
The pixel flaps are simply a firm
press fit into the frames. Line up the
colours so that the white side of the
flap is adjacent to the white side of the
coil PCB and the black side of the flap
is adjacent to the black side of the coil
PCB (see photo).
Sit the bottom tab into the hole in
the frame, and then gently rotate the
upper tab into the hole. Once all the
flaps are installed, check that the pix-
els will all flip freely. This can be done
by rotating the entire assembly in your
hand and allowing the flaps to move
under the influence of gravity.
Connect the coil PCB to the driver
PCB by plugging the headers togeth-
er. The assembly should sit upright
on its bottom edge, with a very slight
backwards tilt. The backwards tilt
will help the flaps to stay in their last
driven position.Connect the micro
The final step for testing is to connect
a microcontroller to control the pins.
You will also need a source of 12V DC,
with preferably at least 1.5A capacity.
The ground and 12V supply are con-
nected to CON3, while the 3.3V/5V
power and logic signals go to CON1.
See the diagrams for either the Ar-
duino (Fig.7) or MicroMite (Fig.8) to