I keep seeing these Bluetooth things on the side of peoples motorbike helmets and get a pang of rampant consumerist desire, my bike may be old and shit but I can look all electro and cool.
Tell me about them please?
There is mobile phone comms?
Rider to passenger?
Local radio rider to rider does that use PVR?
Surely over about 50mph its just too noisy?

It’s so you can tell Norman when it’s time to engage Hyperthrust

Norman was never as cool as K.I.T.T.

Raid the recycling bin add some Humbrol for a tech look.

I’m not up to date with current stuff but when I commuted every day I used one.  As speech recognition improved they became more and more useful and my main use was listening to music.  Other handy stuff is sending and receiving text messages, making and receiving phone calls and hearing satnav instructions.  I’m not keen on phone calls while riding but even stopped it is way easier to use a headset than to take gloves and helmet off, get phone out of pocket etc especially in the pissing rain.

Surely over about 50mph its just too noisy?

I used a unit that allowed me to plug in 3.5mm earphones and used the sound isolating type so I could listen without ridiculous volume.  The type that put flat speakers in your helmet are more convenient but obviously the sound quality is not even close.  FYI I would always use ear plugs of some type when riding, you have to be stupid not to

We used to use these when I was racing Off-road trucks. They were a god send for communication when winching in difficult terrain. Meant I could get out of the truck and dissappear over a brow out of sight, fix the winch line to a tree or whatever, and give instructions to the driver when ready and which way he sould go, without having to come back and shout my head off. All fitted neatly inside my helmet. This was 10 years ago and the range then was about 100 metres. I imagine if anything it is better now. You could pair them with any other user with a set, just like a phone. Never saw any with 3 way comms though back then.

The new Shoei helmets have a nice looking integration with one of the big brands. I guess it makes it all a bit specific, but it does look quite slick.

I’m waiting for a proper HUD without a hug bunch of external gubbins lashed on.

I use an Interphone (F4 I think) mostly for just having the radio on during commutes, sometimes for podcasts with the flat internal speakers. Audio quality is ok,not brilliant but I find that using radio as an example the presenters are audible, music is fine, I just can’t hear people calling in to the “show” either because of my dodgy hearing or the lower quality of the audio reproduction from the phone-call. I do also wear earplugs.
I bought the helmet and headset at the same time so I selected a helmet with either voids for the ears or removable pads around the ears (can’t remember which).
At motorway speeds phone calls may or may not be audible I’ve had both and it seems to be more related to the quality of the phone connection than anything else.

It’s been pretty reliable for 3+ years of near daily commuting in all weathers of 30-45 minutes each way but now the battery which is not technically replaceable (although I have found online details for doing it) is only lasting for 4-5 days.

I have an AutoCom Air which I like mainly because it’s very small and discrete. Just a couple of tiny buttons stuck on the side of the helmet, not a big fat chunky thing like most others I see around. Mainly use for listening to podcasts, but also useful for taking calls on the move. Not tried using siri or anything fancy. I wear earplugs and have little speakers inside the helmet.