A tiny I²CMini demo

2019-12-17

[First some obligatory last-minute shopping stuff. The Excamera Labs store will be closed Dec 21-31, as I'm headed to Berlin for the holidays. US orders made on the 20th should arrive before the 25th. Amazon will continue, of course, and you can buy Gameduino 4.3", the Gameduino 7", and the I²CDriver Gold package. Everything will resume Jan 2nd.]

I²CMini is a tiny interface between USB and an I²C circuit. Here is an I²CMini, two I²C 7-segment LED modules, and a carrier board. It's all you need to make a USB-connected bright red 4-digit display.
First solder the parts to the board, and plug in. The two LEDs should show horizontal bars, showing that they are powered up and waiting for an I²C command.

From here on everything is software. You can use the I²CDriver GUI, Python, the command-line or C++ to drive the DIG2 modules. I'm demonstrate in Python.

To start with, import the i2cdriver module and connect to the I²CMini:

    >>> from i2cdriver import I2CDriver, EDS
    >>> i2 = I2CDriver()

The ask it to do a bus scan. The two LEDs appear at address 14 and 15 respectively

    >>> i2.scan()
    -- -- -- -- -- -- -- --
    -- -- -- -- 14 15 -- --
    -- -- -- -- -- -- -- --
    -- -- -- -- -- -- -- --
    -- -- -- -- -- -- -- --
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    -- -- -- -- -- -- -- --
    -- -- -- -- -- -- -- --
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    -- -- -- -- -- -- -- --
    -- -- -- -- -- -- -- --
    -- -- -- -- -- -- -- --
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    -- -- -- -- -- -- -- --

Next create two devices to drive the DIG2s like this

    >>> d0 = EDS.Dig2(i2, 0x14)
    >>> d1 = EDS.Dig2(i2, 0x15)

You can put decimal numbers on the displays with

    >>> d0.dec(12)
    >>> d1.dec(34)

And a clock is almost as easy:

    >>> from datetime import datetime
    >>> t = datetime.now()
    >>> d0.dec(t.minute)
    >>> d1.dec(t.hour)

And to run it constantly as a desktop clock, you can do

    >>> while True:
    ...     t = datetime.now()
    ...     d[0].dec(t.minute)
    ...     d[1].dec(t.hour)
    ...

That's all there is to it. These parts are included in the premium packages in the I²CMini campaign.

Thanks for reading.