Monster iCruze displays

A nice 2 x 20 backlit surplus display very useful for DIY projects

As used by Time Nuts

Last update: 11-04-2010 

This page will be updated as I get new data.

Some history:

Around 2005 an audiophiles (or should I say Audiophools?) accessories company called Monster Cable Products Inc, launched an innovative system to connect an iPod to the car audio system, making the carís radio think the iPod was a CD changer and thus allowing to control the iPod from the radio controls, including the mounted on the steering wheel, if any.  The system had an optional $100 display (which is what this is all about) which shows the song title and artist name, as stored in the iPod files.


      An iCruze complete system                                                           The display (the text is simulated)

For some reason that I ignore, but probably a sales fiasco since the basic system was sold by some $200, this nice system became a kind of Ford Edsel.  If you try to search for any reference about it in the Monster web site as I did ( you wonít find anything, as if the system had never existed (anyway internet has its memories and yes, it did exist).

The first time I knew about those displays was in the Time-Nuts list.  One member of this list, Didier Juges KO4BB, had designed and built a standalone monitor for his Trimble Thunderbolt GPSDO ( and released his code under GPL.  Other members of the list soon noticed that copies of Didierís monitor were being sold on eBay by a Chinese store.  The owner of this store is Bob Mokia (, a well-known supplier of surplus time nuts goods.  He got a batch of iCruze displays (probably the actual factory was on China), replaced the microcontroller board with one of his own, programmed it with the Didierís code and made some changes to the original cable.

fluke.l display

Didierís Thunderbolt monitor in the iCruze display, as sold by fluke.l

Another member 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 someday.


The monitor integrated in Arthur's GPSDO, among other of his Time Nutsí stuff

I 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

I 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.

After reading 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 .

Later I received several emails from more list members who had also bought some displays and wanted information.  This is why I started this page.

I 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 or KS0066; 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 installed.

 Scope image

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 Monkey Composer.

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.

If anybody 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, isn't is?


Go to TOP

Why do I say Audiophools? Take a look at some items now sold by Monster: Speaker cables with magical properties