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Old 08-19-08, 08:07 PM   #1
Road Fan
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Turn Signals?

I wonder if bikes should have turn signals? They'd help with maintaining a signal while you're waiting for clearance to turn, would be morevisible at night, and would allow two handed riding while signalling.

In another thread, I was asked how they could be made ("Talk through this a bit ... ). So I babbled the following:

For a road bike, rear ones on little booms sticking out from the seatstays above the wheel sight line, maybe total 12 inches apart. The half-power light distribution cones should be perhaps +-25 degrees from central axis. The booms should be rigidly attached to the seatstays, but able to flex and return or be straightened to resist permanent bending, and easy to correct if a large bend occurs while the bike is parked. LED with reflector/light director should be powered from a battery, and the battery float-charged either by a dynamo, an integrated solar panel (integral with the wheel? a photovoltaic dork disk?), or charged at home (no, this one is not float-charging). Size each lamp maybe 3/4 inch diameter each. dual thumb switches one on each hbar side. Similar lamps in the front, attached to hbars.

For a touring or commuting bike, integrate the rear booms with the luggage rack, or make a tail/turn rear lamp cluster.

In a more elaborate system they should share a power system with head/tail light, unified wiring harness in the frame (I know, getting a little constructeur here ..., but it needs to take up minimum space). Extruded flat-conductor cable manages heat extremely well, fits into small spaces, and is mechanically very robust. It can be folded to fit into little frame holes. I think the cabling should be neat and out of sight. The total power draw averaged over a ride for such turn signals is miniscule compared to head and tail lights, even LED, due to the low duty cycle. The power budget should also manage a brake light.

Problem here is designing the switches. The turn switches are easier for upright bars or trekker bars.

I see a lot of possibilities. Problems, too, but I think these are managable challenges. There's some curcuit design needed, probably to combine the output of multiple power sources, and to provide a regulated bus for the whole bike light system. It can be integrated into a powerful LED headlamp, like a Vega or Dinotte. With a dynamo, you can even add the USB charger for your cell phone or Garmin. An HRM can be on the same power system, with suitable voltage shifting. but now we're getting expensive.

Ok, put the power systems engineer back in the box now.

Any thoughts on some of these ideas? Has anyone seen much in the way of turn signals for bikes?

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Old 08-19-08, 09:40 PM   #2
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Wow, lots to think about. I wish I had a dynamo so I could play around with some of this!

My biggest concern would be the switching. Most people won't want to take their hands off, especially if they are braking too. But you wouldn't want to accidentally turn them on, and it would be very nice if they turned off when the turn was completed as in a car. I still can't ride in the straightest of lines, so that part might be a concern.

I think a hub dynamo-powered system would work great since it is always active. If you made a 0.5W system that leaves 2.5W for front and rear lights. In the daytime you would not want lights but you would want turn signals, so you would need to switch between the lights and something else (recharger?) but keep the turn signals active.

Don't know how much sense that makes; it all works in my mind but the words don't come as easily. I'm curious to hear what other ideas people have.
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Old 08-19-08, 09:48 PM   #3
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An interesting idea. But I think it wouldn't be much useful without the ability to maintain traffic speeds (a la motorcycles). I wouldn't rely on them myself unless I were consistently matching the speeds of vehicles around me.
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Old 08-20-08, 09:03 AM   #4
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Hand signals?
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Old 08-20-08, 10:09 AM   #5
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http://www.bicygnals.com/

Have not used this product, just found the link.
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Old 08-20-08, 02:07 PM   #6
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That's a nice link jsharr.

I was talking about bike signals with a friend of mine just a couple of months back because I remember decades ago how some bikes did have little squareish units with arrows on them for rear signaling. Seemed kind of cool but guess they just weren't visible enough.
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Old 08-21-08, 01:04 AM   #7
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Another one to check out:

http://www.tobesafeandsound.com/cont...ety_light.html
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Old 08-21-08, 05:47 AM   #8
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Deal Extreme sells bike turn signals.

I think the flaw is that motorists are unlikely to notice them as they don't expect bikes to have turn signals.

OK at night maybe but they'd have to be very bright to be noticeable in the summer sun.
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Old 08-21-08, 08:00 AM   #9
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If a cyclist relies on the ability of drivers to recognize and act on some signal, they're going to be a messed up cyclist in short time. Turn signals work on cars because they're expected and recognized. On a bike, you're asking for trouble. I would find them more harmful than good.
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Old 08-21-08, 10:25 AM   #10
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turn signals might be nice if you're riding at night and don't have a jacket with reflective sleeves, but beyond that I don't think they're useful for several reasons. First, cars aren't expecting them. Second, the lights are too close to the center of the bike, so they'll just look like a flashing amber light, whereas on a car they are seven feet apart. Third, arm signals work and they're very obvious. With an illuminite jacket and gloves I am very confident that cars behind and in front of me understand that I'm turning.
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Old 08-21-08, 08:04 PM   #11
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here's another interesting alternative...

http://www.blt-lights.com/product/signal_vest/
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Old 08-21-08, 10:51 PM   #12
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Quote:
Originally Posted by littlewaywelt View Post
turn signals might be nice if you're riding at night and don't have a jacket with reflective sleeves, but beyond that I don't think they're useful for several reasons. First, cars aren't expecting them. Second, the lights are too close to the center of the bike, so they'll just look like a flashing amber light, whereas on a car they are seven feet apart. Third, arm signals work and they're very obvious. With an illuminite jacket and gloves I am very confident that cars behind and in front of me understand that I'm turning.

This is a dumb argument. The lights are bad because cars don't expect them and cars don't expect them because... we don't use them because cars don't expect them? Come on. As for your second point about distance... you could easily set up a system that connects to a rear rack that has the lights eight inches apart. Drivers will be able to see and decipher those just fine, you just don't give them enough credit.

And finally, any kind of turning signals or lights do not replace common sense when riding a bike or a car.
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Old 08-22-08, 08:34 AM   #13
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One area in which I could see turn signals causing confusion would be lane position. Even if the lights are 16" apart (8" offset per light), if you are riding close to the right curb and put on your left turn signal, that flashing light is still only 20" or so away from the curb.

If I was driving a car at night, and saw a flashing light 20 " from the right curb, I would assume a right turn is imminent from the vehicle ahead, not a left turn. I am also using the assumption that I am far enough back and it is dark enough for me not to realize that the vehicle ahead is a cyclist.

I think that if one begins to ride with turn signals, then one must think of lane positioning prior to using them. This is somewhat self defeating in my opinion, as you have to move left prior to indicating a left turn.

Just my two cents.
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Phobias are for irrational fears. Fear of junk ripping badgers is perfectly rational. Those things are nasty.
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Old 08-24-08, 10:13 AM   #14
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Quote:
Originally Posted by jsharr View Post
If I was driving a car at night, and saw a flashing light 20 " from the right curb, I would assume a right turn is imminent from the vehicle ahead, not a left turn. I am also using the assumption that I am far enough back and it is dark enough for me not to realize that the vehicle ahead is a cyclist.
Ah, good point. My thoughts on the validity of the turn signals from the last thread:

Why don't I see turn signals on bicycles?

Anyway -- how to make them work?

Activating them would be the easy part. It's hardly worth a paragraph.

Auto-off would be nice, but I'm not sure how to make it sense when to turn off without getting triggered by other movements. The front wheel & handlebars don't rotate very much (not much more than during typical straight line wobbling), so maybe detecting the lean of the bike would be better. But, that could be thrown astray by mid-turn corrections, and may not sense when the bike's going straight again.

A manual switch off would be better, but would still rely on the rider remembering to turn it off. If they forget, they'll just be another vehicle with a flashing signal to confuse anyone nearby. The system would need at least a flashing indicator and maybe a "tin-ker-tin-ker" audible clicker.

I still don't think they're a good idea, but not because of technical reasons.
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Old 09-01-08, 03:24 AM   #15
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http://www.abc.net.au/tv/newinventors/txt/s2245783.htm
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Old 09-01-08, 09:09 PM   #16
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1) the lights have to be powerful enough to be unmistakably daytime-visible from a range of at least 200 meters in direct sunlight if they're going to be any use to a highway rider like myself. Nova BULL, Whelen TIR3, DiNotte 140/400/600, no problem. Dinky little lights that look bright from a few feet away...? Uh, no.


Nova BULL at 200 meters. Zoomed shot.

2) the lights have to be clearly discernible as "left" or "right" from long range, which means giving them plenty of separation and providing a powerful red taillight as a centerline reference. Nova BULL x 2, Whelen TIR3 x 2, DiNotte 400/600, no problem. Cute toy lights that look OK at close range... forget it.

3) if you're going to replace your arm signals with lights, you also need front turn-signal lights and a daytime-visible headlight to provide centerline reference.

4) I have four bikes to equip. So far.


Think I'll just stick with the arm signals My bike's already packing enough weight in light systems without hitching up six more Nova BULL strobe heads just to save me making an arm signal. If you want to build one anyway, the Novas have a steady blinking mode that's ideal, however, and they do come in amber. Just supply ~10-16 volts and they'll do the blinking for you. Use the SYNC wires to team the front & rear lights to eachother... I'd set them to alternate front-rear-front-rear so you don't put as much demand on the battery pack. Switch 'em to DECIBLAST mode if you really want to get noticed

Last edited by mechBgon; 09-01-08 at 09:23 PM.
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