Readme.md update - required modules on Pi Zero W

[pvint]

On my Pi Zero Wireless I needed to add to /etc/modules.conf:

i2c-dev 
i2c-bcm2708

I'm not certain I needed both of those, and I have to set up another one so I will will confirm and submit a PR for the readme update.

I cannot assign this to me, but consider this self-assigned. ;)

[edlins]

Cool, those look to be the same as the B+. I didn't know the Zero used a 2708. I only have one entry in /etc/modules, i2c-dev. BTW, that's the module that exposes the i2c-bcm2708 driver via the /dev/i2c-n device files to enable non-root userspace access to the i2c buses. Neat trick.

[edlins]

Also, have a look at my master branch netinst script. That shows how to configure a naked Raspbian system to work with i2c, combined transactions, and libPCA9685 including the module activations. The entry added to config.txt enables the i2c_bcm2708 module and the entry added to modules.conf enables i2c_dev (I think).

[pvint]

I'll take a look at that - sounds cool (the netinst)!

I have one more device to get going - I will try to make a point to test the netinst script of yours before simply applying my image. ;)

BTW: Your little lib here is now in use controlling lighting on a sailboat! You did the heavy lifting for me and in a way that I found readable, flexible, useful, and light. I owe you a beer but they don't mail well.... drop me an email with your address and I'll send you a couple of my boards (let me know if you have a preference for the I2C addresses)

Also, see https://github.com/pvint/fade9685 for my messing around with a CLI for controlling my lighting. It still needs a lot of improvement, but it's working great!