Arduino etc. (was: GRID DIP OSCILLATOR)

hi ,
there is no CS pin ,the lcd's have  some lcd backpacks with PCF75... something , it's actually an I/O port extender ..
Anyway i throw in the idea and for my luck it worked 


so i got away with it   . That was close ...

Hi Zsolt,
do the displays have a CS (Chip Select) pin? It is the usual way to activate/deactivate devices. Your solution should work, too. Or use a Teensy 3.6, it has three separate I2C buses.

BR from Ivan

hi , 
i'm faced with a new practical problem . I have 22 LCD displays on a i2C bus .  Knowing that i can have ~127 addresses  on the bus , when i bought the lcd's i was stupid enough not to check and see that their address register is made up from a fixed part and a configurable part , leaving me 8 possible addresses . 
So now i have to multiplex/demultiplex the 2 bus lines . Like always i was thinking about a trick.
what if i group up my lcd's making 3 groups like , 2 groups with addresses from 1 to 8 , and one group with addresses from 1 to 6 . 
Than i would give the same data line (SDA) to all lcd's (the whole bunch ) and the clock (SCL) separately enabled by software for group 1 ,2 and 3  . 
Could this work , ore anyone done something like this ? ( not the stupid part at the market like i did  )

interesting boards i might try one out , now i'm searching a shield which can interface audio amplifier for an internet radio i want to build ....

Zsolt wrote:
"But i'm using some header files and libraries pre-installed on my computer. So it wont be usable so directly as it is , one must download libraries i also downloaded and add  them to it's own library director  on C: Program files/ Arduino / libraries.......  (the boring stuff..) . Anyway one can post here questions so it should not be a problem helping out"
This is not much a problem. Installing the libraries into Arduino IDE must be done only once. Tell us which libraries and from which URI must be added.
I prefer Arduino Pro Micro by Sparkfun, but I expect converting the SW to different Arduino platforms should make no problem.
"Working with these  little useful boards is so easy , there are hundreds of examples on ''holly google" for absolutely everything , every module or peripheric  once invented and available on the market . I discovered these boards a few  years ago and i started to integrate them in industrial equipment . I can tell that in some particular cases (small and simple applications, not so fast processes ) they can successfully replace an expensive PLC .  (not to mention that programming doesn't need more than an USB cable )"
My new hit are Teensy MCUs https://www.pjrc.com/teensy/

They seem to be 100% Arduino compatible, but they bring many new features and are much more powerful. They have vaste possibilities e.g. in sound processing and MIDI. You just add the Teensy libraries into the Arduino IDE and you are ready to go.

VBR from Ivan