Is the Brake Light On?

[Kiwi_Roy]

Do you ever wonder if the brake light is on?
I was worried that my toe was resting on the brake pedal. The pedal height is not adjustable on the V7 III so I dropped the tread down 15mm with a bracket to guide my foot onto the pedal.

At the same time I added an LED to indicate that the brake light was On, you can see it peeking out between the mirror bracket and the throttle.
This is completely redundant but I like little gadgets on my bikes, it didn't cost anything and made no changes to the loom.
The LED is wired to the front brake switch and of course also lights when I apply the rear brake. Its connected to the switched terminal and ground.
BTW the brake switch has a hot switched wire that would be handy to power up any bar mounted accessories e.g. heated grips or a GPS.

I was surprised to find the bars are not grounded due to the rubber mounting so I  added a jumper on the LH side as there is a handy 6mm bolt there.


As I say it's completely redundant and silly but who cares?
Although in this case it's a V7 it should apply to almost every other Guzzi with a front brake switch.

[oldbike54]

 Silly , well maybe , but I will bet more than one person copies the idea .

 Dusty

[bigbikerrick]

Thats a clever idea! I like it !
Rick.

[tris]

I don't think your simple circuit achieves it it, but if the brake light bulb failed would the LED still light up?

That would be VERY useful 

[Kiwi_Roy]

I don't think your simple circuit achieves it it, but if the brake light bulb failed would the LED still light up?

That would be VERY useful 

No, the brake/tail light bulb is an LED if the bulb failed it would still light up, its very easy to verify the operation in the dark of a garage.
I found the incandescent 7528 (26 Watt) was quite a significant drain on the overtaxed V7 alternator especially with heated gear on stopped at a light, with the motor idling the Voltage could dip down below 12, something I was ignorant of until I added a Voltmeter.
It would be quite easy to monitor the current going to an incandescent light using a reed switch but that would require some additional wiring, the LED I added just to the brake switch.

The CARC bikes monitor the blinker lamps by passing a tiny current through the incandescent bulb, it triggers an alarm on the dash if the Voltage goes over 3 Volts while the blinker is Off.

[Bert Remington]

KR -- when I saw tris's bulb question I laughed because I knew you would answer the challenge.  And you did for an incandescent bulb.  For an LED bulb how about a length of PMMA plastic fiber optic cable such as that used for LED star ceiling lights?

tris -- replace those incandescents with LEDs.  Use Red LEDs with Red lenses and Amber LEDs with Amber lenses.  Spray a little contact cleaner when changing the bulbs and you'll get many times the brightness with none of the worry.  Brake bulb is probably an 1157 and turn bulb is probably RY10W.  Be careful with size of bulb because MG housings tend to be a tight fit.

KR -- WRT grounding the handlebar, does your jumper feed the ground through the steering head bearings?  If so, that's not good for more than milliamp currents.

[Kiwi_Roy]

KR -- when I saw tris's bulb question I laughed because I knew you would answer the challenge.  And you did for an incandescent bulb.  For an LED bulb how about a length of PMMA plastic fiber optic cable such as that used for LED star ceiling lights?

tris -- replace those incandescents with LEDs.  Use Red LEDs with Red lenses and Amber LEDs with Amber lenses.  Spray a little contact cleaner when changing the bulbs and you'll get many times the brightness with none of the worry.  Brake bulb is probably an 1157 and turn bulb is probably RY10W.  Be careful with size of bulb because MG housings tend to be a tight fit.

KR -- WRT grounding the handlebar, does your jumper feed the ground through the steering head bearings?  If so, that's not good for more than milliamp currents.

BR, I didn't want to run any extra wires, fibre optics come under the same category for me but it's a good idea.
Tris, I will check on a way to monitor the brake light current for an incandescent lamp. You may be right about the lamp type, I took that from Superbrights lookup table.
The front forks are well grounded, I have a wire from the frame to the horns under the steering head, besides we are only looking at 10 mA
As promised I knocked up a current triggered switch
A typical reed switch closes at around 20 AT (Amp Turns) of magnetic field so I wound a 20 turns of 20 gauge wire around a 1/8" drill bit.
I used a scrap of Veroboard to mount it on but that's really not necessary,
The big thing when working with reed switches is not to put any stress on the leads otherwise the glass will crack, hold the leads in needle nose pliers while you bend them.

The switch closed at about 0.75 Amps and opened again below 0.5 Amps, just about perfect for an incandescent stop light.