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Dynamic Brake Light Amateur

10K views 27 replies 7 participants last post by  Panzermann 
#1 ·
Dynamic Brake Light is available in EU/ECE areas in conjunction with ABS Pro, the theory being that a flashing light better attracts attention in emergency braking situations.

In idle on-line chit chat with Lawrence of Suburbia, we discussed additional brake light options for the LC, without the exorbitant expense of the Skene P3. After some research, I discovered a module that flashes fast-slow-steady on each application of the brakes, for just a few dollars plus, perhaps, some ingenuity to avoid CANBUS-related error messages.

I also came across a still-fairly-cheap module with more options, including actions on moderate and heavy deceleration - the g-force Stop Alert. It is intended for modulating the third/centre brake light on cars, as it remains illegal to have flashing brake lights in most countries, including Straya. being intrigued by such an elegant design for few dollars, I decided to go ahead. If pressed by the constabulary at any stage, I could perhaps feign ignorance and suggest that maybe an EU spec model with BMW Dynamic Brake Light slipped through. 0:)

While awaiting delivery, my mind started to think about ways to obviate CANBUS errors, either:
  • using a dummy load (ceramic coated wire resistor) to simulate the stop-light load and trigger a relay to power the stop-light via the module on a separate supply line; or
  • apply an additional dummy load in parallel with the module inputs, with as high as practicable resistance to stop CANBUS errors but avoiding an overload detection on the circuit.

Today I cut the stop-light lead to install the module and found that the light draws 0.26A (about 4W). I happened to have a 33 Ohm resistor on hand so as a test added that to the circuit, in parallel with the LED stop-light. No faults appeared, showing that the line can handle at least 240%, and proving that I could, if necessary, use the second and simpler of the options I had determined above.

I then test wired the module with no dummy load, and to my surprise no faults showed - the latent load of the module itself and/or the short duration of the flashes must be sufficient to make the CANBUS think the circuit is OK. In the normal case if the circuit is interrupted and then 'healed' (e.g. by simply removing then replacing the plug to the tail light) the dashboard bulb warning disappears, but the fault tally increases by one each time this occurs. I checked using my GS911 and confirmed that the flashing action of the module does not, in fact, cause any faults to be detected. I used double sided tape to attach the unit vertically and level on the RHS of the tray under the seat, using the default position of wires pointing forwards.

So the device really is plug-and-play CANBUS safe. I'm using the default settings at the moment but in time will look at the instructions to change them to my preference should I feel the need to.
 
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#2 ·
...in idle on-line chit chat with Lawrence of Suburbia, we discussed additional brake light options for the LC, without the exorbitant expense of the Skene P3. .

I'm going to have to stop playing with you, Panzermann - your bright ideas are costing me a fortune!:surprise:
 
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#3 ·
As I have been jonesing for the dynamic brake light for some time, this piques my interest. However, it is important to remember that any instructional post over 5 lines demands pictures otherwise it doesn't exist and can be considered trolling. Which model did you get? There are 3?

Unless your LEOs have far more time on their hands than their brethren in the USA, I don't think you have to worry about being stopped.
 
#4 ·
I got the top model, with g-force (sounds like it will give me superpowers!) as per the link above.

I hardly thought it worth photos seeing it was so simple, but installation shown below in order to retrieve my reputation. The brake light lead is grey with black tracer and occasional yellow band. (Without green band is the tail light).

As you say, most LEO will ignore it, especially as there are so many flashing LED tail ligts on bicycles these days around the roads. Victoria Police will book you for three km/h over the limit and if they feel like it, go over your bike for anything non-compliant (usually targeting the boy racer types, though). I know others who have had flashing brake lights installed for years without a problem though.
 

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#5 ·
Notably, the arrows on the circuit board indicate alternative mounting orientations, but you need to go into the programming function to set these in order for the decelleration to be measured correctly. Wires forward and vertical is the default, and was easy to accommodate.
 
#7 ·
Thanks, non "boy-racer type." geriatric racer maybe?

do you have a bigger shot that shows the orientation vis a vis the under pillion seat area?

but it appears horizontal?

Are the instructions good?

and thanks!
I thought the photo showed sufficient context for the location to be intuitive, but then I have been warned by Lawrence of S for using the word intuitive (even subconsciously) on this forum in relation to technical matters. I don't have a wider shot at hand but the module orientation is, in fact, vertical - stuck to the vertical edge of the plastic tray under the pillion seat RHS, with the wires facing towards the front of the bike (wires are horizontal - that may be where the confusion arises - my Germlish isn't perfect). The perforated matting in the picture sits at the base of the tray - under my puncture repair kit to stop is sliding around and scuffing the tray. The module is angled downwards at the back a bit so that its top edge is horizontal when I'm seated on the bike.

Instructions are linked in the last para of the initial post - not written in Germlish unfortunately, but some other variation of the English language.

Wiring is simple - cut the bike's stop light wire :surprise: (grey with black tracer and green bands) and crimp a supplied female bullet connector to the supply side and a male one to the stop-light side. You can see where I've cut through the woven loom tape to extract this wire.

On the module, crimp a male bullet connector to the red lead and female to the yellow lead; attach to their respective connectors on the bike.

The black lead goes to an earth point (any brown wire on the bike). Rather than disturb the loom further at the point at which I had cut the stop light lead, I extended the black to run to the accessory socket lead, which is more accessible. For this, I used my own T-connector rather than the supplied one which is intended to receive a (not supplied) spade terminal it seems.

The white wires are for programming if you don't wish to use the defaults (many combinations are available) - initially a loop which ensures the module is in default mode, but I cut them (at marginally odd lengths to avoid the need to insulate) and tinned the tips for durability.

Re-programming to select non-default options is by connecting together the white wires for short duration to select an option and for long duration to confirm and move to the next option set. The technique is a bit like the bike's dashboard options of tap to select an option then hold to confirm - without the benefit of a textual dashboard display. I'm presently using the default settings for all the flash options but would like to make use of the 'lock-out' option to reduce flashing when using the brakes frequently in stop-start traffic. I may also change the flash sequence for some options to fast-slow-steady. I'll need to do that systematically though and tick off a check-sheet so I don't get lost! If all fails, I can hold together the two white wires for a number of seconds to reset to defaults, and start again.

The flashing on application of the brakes certainly works (five on-off flashes in about a second, then full on) but I can't vouch for the g-force initiated flashing as it's a bit hard to look back there when under moderate or heavy braking. I'm thinking of temporarily wiring in a tell-tale LED to confirm my parameter settings.
 
#10 ·
Having disposed of his Racing Red R, LoS sent me the remains of his additional LED hardware that he was in the midst of installing when decision-time hit him between the eyes.

To answer a PM from another forum member, I tested LoS's GS-100A flasher module in place of my Stop Alert. The GS-100A is a basic flasher that modulates the brake light to give four quick flashes, four slower flashes, then solid. Unlike more sophisticated units, that is the limit of its functionality - i.e. it has no programmable modes or accelerometers, and flashes in this manner with every application of the brake.

I found that it would generate a bulb error every time it flashed 'off', indicating it had too low (or nil) latent current draw (I didn't measure) and the CANBUS assesses the bulb circuit as being open (equivalent to a blown bulb or faulty circuit). I found, though, that I could avoid the error by connecting a resistor to the input side of the module, with the other lead from the resistor connected to earth; this provides sufficient current draw when the flashing is in the off part of its cycle to satisfy the CANBUS that all is well. The resistor I had on hand was a 470 Ohm 5W ceramic coated wire resistor, which would have drawn only about 0.025 Amps, or 0.3 Watts, so wouldn't get hot in use.

So if you want a cheap option for modulating the LC's LED stop light and are not concerned about more sophisticated functions (or about potentially annoying following drivers with incessant flashing in stop-start traffic) then the GS-100A is cheap and viable. With the addition of a resistor to the input side as described above, I can assign the comforting words 'CANBUS compatible'.
 
#11 ·
BTW, I tested the deceleration function of the Stop-Alert in the garage today. Wheeling the bike forward then braking hard produces a series of rapid flashes then solid. Similarly if I have the stop-light already illuminated, the brake light flashes rapidly then returns to solid.

I still plan to add a temporary tell-tale up on the handlebars so I can observe the functions while riding and tailor them if I feel the need.
 
#12 ·
Until now I have used it on the default settings on the Stop Alert but wanted to see how it reacted under differing levels of braking. As @Lawrence of Suburbia mused, if a brake light flashes and you don't see it flash, did it really flash? So today I fitted a tell-tale LED to the RH handlebar, wired to the modulated brake light.

I also took the opportunity to change some of the default settings to my preferences, such as invoking the time-out period to avoid extraneous flashing when in stop-start traffic. That was easier said than done, as the programming function is accessed and parameters adjusted by momentarily shorting the two white wires, then holding them together for a couple of seconds to confirm settings. With eight adjustable parameters, four of which are replicated across the three modes of Initial Power applied, Medium Braking Force and High Braking Force, I found it a bit tricky at first to keep track. I found myself having to say each step out loud just to confirm where I was up to, and counting aloud the number of flashes for each parameter to know what the current setting was.

I used a 12V power supply rather than the bike's, to avoid having the ignition switched on for ages. I also wired in a temporary switch across the white wires for reliable periods of connectivity (momentary or +2 sec).

After a while, I got the hang of it, and should my tell-tale indicate a requirement for further adjustment, I'll be much better prepared.
 

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#16 ·
...if a brake light flashes and you don't see it flash, did it really flash?

I've been losing sleep over this, PZ, so sourcing some bits from ALDI, IKEA, et al I rigged-up this device, yet to be finalised. The kite-shaped part behind the bike will eventually - when finished - comprise many small perfectly-aligned mirrors, so you will be able to see at a glance in the bike's rear mirror if the LEDs are, in fact, flashing.

http://images.mcn.bauercdn.com/upload/297171/images/540x360/yamaha-triple-engine.jpg?mode=pad
 
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#13 ·
I could use something like that with the Hex EZCAN. Currently I can only verify what it's doing by having another rider behind me. It is, though, much easier to program, needing only a laptop and USB plug.
 
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#15 · (Edited)
Sounds entirely intuitive, PZ!
 
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#18 ·
I adjusted the brake force settings for Moderate and Hard braking to their maximum (the latter 0.8 G) and it's now working how I want it to.

Quick flash then steady for normal braking, one flash then steady during the 9 second wait-out period.

Quicker flash then steady for Moderate braking (including during the wait-out period).

Similarly for Hard braking but qicker and for longer.

Neat.
 
#19 ·
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#22 ·
Hi Panzermann,
I was thinking about what did with this cheap accelerometer/light flashing module G-force Stop alert, so I was wondering why couldn't one use the Hex Ezcan which has a purpose built pigtail outlet for brake lights- it already has the built in flashing sequences and uses the motorcycles built in accelerometer data via the canbus. Since it has a accessory brake light output one could connect that to the same wires which you tapped into the same way and need not buy this module that you used.
Do you think I am making sense, and have you or someone you know tried this out?

On a seperate note, I was thinking of buying the Canswitch from this rival of Hex ezcan, and they also offer same functionality as Hex, but with the added garage door opener capability programmed with your ABS button, and much more. But the darn thing is USD $ 216 vs $169 for Hex.
-R
 
#23 ·
Hi Rohan

I understand the Hex ezCAN is designed to operate four accessory circuits, one of which can be configured to power a (modulated if required) accessory brake light - it doesn't modify the operation of any existing lights or functions of the bike.

If you were to cut the lead to the existing brake light, rather than add a further light, and power it via the ezCAN, you would trigger a LAMP fault code on the dash, but otherwise I expect the light would operate as programmed by the exCAN like you suggest.

To get around the LAMP fault, you could get an appropriate resistor normally used when replacing regular incandescent indicators with LED equivalents, and attach it to the cut circuit to create the current draw expected by the ZFE.

The g-Force Stop Alert seems a simpler solution, unless you specifically wanted the programming sequence available from the ez-CAN.

I have often thought a means of triggering a garage remote from the handlebars would be nice, but with the CANBUS system this is a little tricky to rig up without making use of the CANBUS coding as Canswitch has. I don't know whether the Canswitch has a remote inbuilt (unlikely as there are variations in frequency and modulation) or whether it simply provides a Normally Open circuit to use to wire into a user-supplied remote. Pat from the F800 Owners forum came up with a very elegant solution.
 
#24 ·
DYNAMIC BRAKE LIGHT.
Braking in dangerous situations is one of the biggest safety risks for every motorcyclist. Especially when following traffic is unable to react in good time. This is why BMW Motorrad developed the dynamic brake light, which helps to better alert the drivers of following vehicles to the braking motorcycle in front of them. With the dynamic brake light, BMW Motorrad is the first manufacturer in the world to transfer this proven safety concept, which up to now had only been known in the automotive sector, to motorcycles.
The brake light's additional function, which is currently still limited to the EU and ECE area, is split into two levels. Level one is activated by rapid deceleration from speeds over 50 km/h. The brake light warns following traffic with a frequency of 5 Hz. In level two, the hazard warning lights system is additionally activated by panic braking to at least under 14 km/h. This remains active until the vehicle accelerates to a speed of at least 20 km/h again.
The dynamic brake light is only available as a piece of optional equipment ex-works in connection with ABS Pro (in connection with optional equipment Pro Riding Modes) from model year 2016 onwards for the models R 1200 GS and R 1200 GS Adventure and the S 1000 XR. The tourers K 1600 GT, GTL and GTL Exclusive will have this safety advantage as standard from model year 2016.


Just wondering – do any countries have DBL in conjunction with ABS Pro on their R1200/1250 LC? I recently managed to convince a LEO (after he had booked me for speeding ... 😕) that my Dynamic Brake Light Amateur that he had noticed (flashing brake light) was 'a BMW thing'. Does it exist in real Roadster life?
 
#25 ·
Well, the feature would not engage if you’re actually using the brakes. It would only react to deceleration from downshifting hard. I have aftermarket rear lights with that function, and the deceleration feature is near useless. It takes hard g-forces to trigger it on the highest sensitivity, and we’re talking going 45 mph in second then dropping into first with a closed throttle level of deceleration...basically making the rear tire skip.
 
#26 ·
Well, the feature would not engage if you’re actually using the brakes. It would only react to deceleration from downshifting hard.
Not so, ZNG. It’s designed to work in conjunction with heavy braking (in particular emergency braking, which achieves much higher negative G’s than you will ever achieve with hard downshifting).

 
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