Today the new BT halo hub turned up. To set it up I have to be able to distinguish orange from red from green: no chance. And blue from purple, again: not a hope.
Bi-colour
[1] LEDs are a work of Stan. I've been known to modify battery chargers and the like to turn them into two physically separate LEDs so I can tell what's going on.
Because of the way colour vision works, point sources such as blinkenlights are particularly hard to determine the colour of, and (as discussed in a previous thread) even with 'normal' colour vision, people often disagree on what colour a given wavelength actually is.
When I design things, I try to never use colour as a sole indicator of anything. I might have a row of different coloured blinkenlights on a widget, but you can always tell the difference between the red power light and the orange network activity light, because the power light's the one on the left with 'Power' written under it, and the network one's the one on the right with 'Network' written under it. If I'm designing a document or graphic, I'll make it make sense when rendered in greyscale. It's not hard. Indeed, it always feels like you'd have to go out of your way to do otherwise.
(Flashing complicated patterns is a lesser work of Stan, because it's time-consuming to interpret and hard to label, but at least it's possible to decode them eventually.)
What I really don't grok, but have observed countless times in the real world, is that colour-vision-people, when made to describe the status of a row of well-labelled blinkenlights as above, will say things like "The orange light's flashing" instead of "The network light's flashing" (at which point you're left scrolling through the manual to work out which one's orange). Happens all the time. They won't ask for the big chopping board, they'll ask for the red one. It's like colour overrides both reading and semantics in their fuzzy little rainbow brains.
[1] Two LEDs in one housing, giving three possible colours, depending on which are switched on.