Radar detector warning system

[SMOKEU]

I've got a Beltronics RX65 which has a 3.5mm audio out jack. I can connect earphones to it, but I don't want to as I don't want all the wind noise so I wear ear plugs. I don't have the money to pay for those expensive wireless systems that I've seen around, but I would like a simple system that is cheap to buy or make myself. I was thinking of possibly having a light attached somewhere in my helmet that flashes every time the RD goes off. I don't mind having a cable going from the RD to my helmet.

Any suggestions?

[bogan]

If you can max the volume (or it comes maxed), a low voltage LED by itself, or with res and cap should do the trick. Prick of a thing to be wired to your bike though, just spend the extra hundy bucks and get some wireless multifunction fandangled-ness.

[Gremlin]

I went for expensive wired system myself.

Anyway... if you use custom moulded earplugs, if you fork out for another set, you can get more expensive ones that have earphones embedded, then you can run wire direct to earplugs. Other option is perhaps a speaker? Relatively simple to wire up I would think.

I used the (I forget the name) but the red blinking light with sender from radar detector etc, problem was, with the battery I wasn't really certain if it was on, or flat, or if it would work. Hence going with wired instead, no batteries.

Anyway, YMMV.

[SMOKEU]

If you can max the volume (or it comes maxed), a low voltage LED by itself,

So if I just wanted to do it on the cheap until I can afford a proper setup, is it as simple as connecting an LED to a standard audio cable, then plugging the cable into the 3.5mm output on the RD?

[bogan]

So if I just wanted to do it on the cheap until I can afford a proper setup, is it as simple as connecting an LED to a standard audio cable, then plugging the cable into the 3.5mm output on the RD?

I would be hesitant to do that without first figuring out what the output impedance of the unit is, which is to say, how much current it can sink/source. Then you can use that info to choose an LED that will not draw any more than said current at full 'noise'. I think generally too much load on the output will just load it down, and reduce signal quality, but you could also kill the audio output completely which I why I'd advise a bit of research.

[bogan]

Actually I just checked wikipedia for ya

The impedance is around 100 Ω, the voltage can reach 2 volts peak-to-peak with levels referenced to -10 dBV (300 mV) at 10 kΩ, and frequency response of most modern equipment is advertised as 20 Hz - 20 000 Hz (although other factors influence frequency response).[citation needed] This impedance level is much higher than the usual 4 - 8 Ω of a speaker or 32 Ω of headphones, such that a speaker connected to line out essentially short circuits the op-amp. Even if the impedances would match, yielding the theoretical maximum power transfer of 50%, the power supplied through line out is not enough to drive a speaker.

you're looking at around 1.2V minimum for LEDs IIRC, so your driven impedance must be 100/(2-1.2) = 125ohms, which is a peak current of 2/125 = 16mA

As long as you find an LED which has a forward current less than the calculated peak current (calculated for its forward voltage) I would say you'll be all right, get two and wire one to each channel and ground for double the light.

[onearmedbandit]

Smokeu I wear earplugs with my intercom and I can hear clear that clear as a whistle. Speakers like these (although you'll only need one) held in your helmet with velcro will get the sound through and be comfortable.

[SMOKEU]

Smokeu I wear earplugs with my intercom and I can hear clear that clear as a whistle. Speakers like these (although you'll only need one) held in your helmet with velcro will get the sound through and be comfortable.

Sweet, are they easy enough to hear when the speedo is reading rather "excessive" speeds on the open road? My helmet is pretty damn noisy as it's not quite a perfect fit.

[onearmedbandit]

Sweet, are they easy enough to hear when the speedo is reading rather "excessive" speeds on the open road? My helmet is pretty damn noisy as it's not quite a perfect fit.

I can hear my g/f's voice clearly up to 140km/h (on the track of course), above that you can still hear but can't really make out words properly. Mind you this will be a lot to do with wind noise coming through our mikes. With no microphone, and the noise just being a high tone, you should be mint. For less than $20 it's worth a try. Just search for thin flat speakers that sit over your ear rather than in it.

[SMOKEU]

I can hear my g/f's voice clearly up to 140km/h (on the track of course), above that you can still hear but can't really make out words properly. Mind you this will be a lot to do with wind noise coming through our mikes. With no microphone, and the noise just being a high tone, you should be mint. For less than $20 it's worth a try. Just search for thin flat speakers that sit over your ear rather than in it.

Thanks for that, I'll try out the ones you suggested and see how I go.

[pete376403]

I used the (I forget the name) but the red blinking light with sender from radar detector etc, problem was, with the battery I wasn't really certain if it was on, or flat, or if it would work. Hence going with wired instead, no batteries.

Anyway, YMMV.

H.A.R.D (Helmet Assist Radar Detection) www.motorcycleradar.com/products_pg2_4.htm

[Gremlin]

H.A.R.D (Helmet Assist Radar Detection) www.motorcycleradar.com/products_pg2_4.htm

Ah, ta Pete... that's the one. There were also reports by some it was prone to failure and quite temperamental...

[davereid]

I can hear my g/f's voice clearly up to 140km/h (on the track of course), above that you can still hear but can't really make out words properly.

I can hear my wife too..... S L O W D O W N ......

[onearmedbandit]

I can hear my wife too..... S L O W D O W N ......

Last ride we were on she went ripping past me, then issued a challenge. Which I accepted.