I’m planning of using the RGB led also employed in the IMPOO5 breakout for blinkup signalling.
Question is if, in the particular setup as for blinkup (with the polarity sensing to RED), can I connect the BLUE terminal to a pin and use it as an extra optical signal (idea is to use Blue when pairing Bluetooth) - we’ll make sure we switch off blinkup signalling upfront.
I don’t see a reason why not, just to be sure…
Yep, the blue LED is totally independent. The only issue here is that if you’re using a shared light pipe between the phototransistor and the LED, it won’t work because if the blue LED is on then the imp won’t be able to detect a blinkup starting.
Note that there’s no BLE on imp005 though!
thx. The blue LED will only be used very infrequently, and normally not when blinkup needs to be detected. We’re using IMP004m
Oh sorry, I read 005 in your original post 
(the same RGB LED is on the 004 breakout too)