To preserve reverse compatibility, leave .init in place but create new .begin method that returns false if sensor failed to init/respond for some reason.

In Example1_BasicReadings, if(RGB_sensor.begin() == false) then freeze with printed error.

Change to graduated examples:

Example1_BasicReadings
Example2_slightly_more_complex
Exmaple9_crazy weird feature that almost no one will use

See : sparkfun/ISL29125_Breakout#1

I'm trying to work with this driver and I've noticed, amongst other problems, if the init check against the device ID fails, init continues and frequently (always?) returns true.

I'm happy to submit PRs for this and a couple other problems I think I've identified if someone is actually looking and will work with me. Else I'm going to need to write my own driver. Let me know, thanks for the work.

User should have ability to check if new data is available. Don't rely on a delay in main loop. If sensor doesn't have intrinsic 'data available' bit or option then implement internal timer (lastMeasurementTime). available() should return true once enough measurement time has passed or a data bit gets set (I haven't read the datasheet to know if bit is available).

See https://www.sparkfun.com/news/2194

It overwrites setClock settings and multiple Wire.begins can cause crashes on some platforms.