monitor in the iCruze display, as sold by fluke.l
of the list, Arthur Dent, bought one of Bobís monitors
for his Thunderbolt. He
removed the case and integrated the electronics and the
bezel on his own cabinet. He
was the one who discovered the gadgetís origin and found
that some outlets in Amazon were dumping them at $2
each, so he also bought one hoping that he could use it
The monitor integrated
in Arthur's GPSDO, among other of his Time Nutsí stuff
found about the existence of the cheap sources through
Arthur, who kindly sent me a picture showing the
internals of the original unit and the one modified by
Bob. It can be seen that
the original PCB holding the microcontroller was
replaced by a new one with the component side reversed.
The reason for replacing
the board is because Didierís code runs in another
family of micros and it seems that Bob took the hardware
way instead of porting Bobís 8051 code to the Atmel TINY
micro. Another reason could
be that the existing micro lacks the resources needed
for the task.
Pictures showing the inside. The
original is at the bottom and the modified one at top
bought some of the original displays from an Amazon
seller. I had previously made before some gadgets with
LCDs, mainly Frequency Counters and Digital Dials for
Boatanchor radios and I had found that the most
difficult thing to properly finish the enclosure was the
cutout for the display or the lack of a suitable bezel.
These displays have a nice
bezel and even in some cases everything could be
included into the original cabinet in a fashion as Bob
did with the Thunderbolt monitor.
the thread about this subject in the Time-Nuts list I
played with the idea of recycling the whole gadget
without removing or replacing the microcontroller board.
For some uses just
reprogramming the micro could be enough; or even
innecessary. Imagine that
the toy is just a serial 20 x 2 ASCII terminal, so that
you can send the data you wish to display just to the
current cable. Your code
would have to send the data to a kind of serial port,
instead of to a display driving routine and the display
could be located some distance away, which could be
advantageous in some cases .
I received several emails from more list members who had
also bought some displays and wanted information. This is why I started this
tried to get as much info as I could and began to
reverse engineer the gadget. After capturing the
schematics and once seen how it was powered (it was an
automotive application, but I didnít know what was on
the other side), I applied 12 volts on the input cable
between the red and black wires. The backlight turned on
but nothing appeared on the screen. I began to probe
everything with a scope and the only activity that I
found was a pulse train on the yellow wire, with a
negative going pulse of about 2 ms every 1.6 s; maybe it
is trying to wake up the other side.
This is the schematic, it can be downloades in
both Eagle.sch and .png formats
The display module is a
HY-2002A-803, its info is at
and HERE. As stated in the datasheet
the controller chips are either SPLC80A
they use potted bare chips, so there are not
markings but from a practical point of view both can
be considered the same.
I though that the top row of pads (P1-P6) were for
programming, since this is compatible with standard AVR
means. This has been tested and it
is true. Also it can be thought that the
yellow and green wires going to the external world looks
like the connection to an I2C bus, given they are
connected to the SCL and SDA pins.
It would be very useful if anybody with the right
tools do some tests (send text from an I2C device Ö),
but the tests done so far have been negative.
Looking more carefully I found another signal
related to the above mentioned. It is at pin 9 but it
doesnít go anywhere. There are provisions on the PCB
for a resistor and a diode in series (R11 and D1)
connecting this pin to ground, but they are not
In this scope picture the top trace is from pin 9 and
the bottom from pin 3. Both signals span from 0 to 5 V,
the time base is set at .5 ms/cm and the repetition rate
is 1.6 s (sorry for the quality, but taking this picture
was a kind of a project in itself. Someday I will buy a
scope camera carcass to mount a digital one inside).
If somebody gets more information and find more ways
to use these displays, please send me an email with
your findings and I will post them here.
04-18-2010 Mark Sproul KB2ICI, who bought 20 units for
$2 each (shipping included), tells me that he had
tested the device using an Arduino with a test program
that he made and it seems that the connections are not
I2C. He had connected the above mentioned pads
P1-P6 to a programmer and he had success reading the
code inside the ATtiny. He is going to continue
his investigation and will try to reprogram the micro
to do something useful. The story of his tests
and developments are on his page "Hacking
the iCruze Display".
04-23-2010 Due to the use of Word 2007 for doing
some editing, this page had shown various errors when
viewed on Internet Explorer, while it was ok on
Firefox. I had to make it again, this time using Sea
04-24-2010 Mark has made a big progress on his tests. He
has reprogrammed the micro and a first version of a
program that displays ASCII text using the
current cable is working. A final version will
be ready soon.
04-26-2010 According to Mark, he has finished his
program for the display. It accepts serial data
at 9600 bd with TTL levels. He have the details
on his web page and he will post the code as soon he
finishes some more tests.
04-27-2010 The program, both source and .hex can be
downloaded from Mark's page. He also has posted
a full explanation on how to program the device
and a modification for using 5 volts instead of
12. I didn't programmed any of my displays yet,
because I don't have an AVR programmer.
needs a makeshift programmer, here
is the cheapest one that you can imagine (link
courtesy of Roberto Barrios, EB4EQA). I'm going to
build one and give it a try, since I don't have plans to
use AVR micros, otherwise I would buy the same used by
Mark as described in his page.
11-03-2010 Since there are not doubts about the function
of the P1-P6 pads (programming), the schematic has
been updated accordingly.
At last I
have a working homebuilt Digital Scope
Camera. As soon I take a picture of the
above signals with it I'll post it here.
11-04-2010 I have the picture. What a difference,