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Riding around chicago, I've become very interested in installing a brake light flasher after seeing the one's on the Chicago Police cars here. Very cool. When brakes applied, it does about 3 flashes in 1 second and the holds steady.

The I idea I had was this. The existing system has battery -(A)-> brake level -(-> rear light -(C)-> Ground. Cut point ( and splice in a "Normally Closed" Relay between the two lights. At this point if I did nothing more, the brakes would behave as normal.

The add a control circuit drawing it's V+ from the supply side of ( as well. Have that supply feed a 7805 regulator that then supplies 2 subcircuits. One runs a 555 time on 50% duty cycle set to flash 3 times a second. It's output would run to the relay, so when 555 low, relay not triggered and lights on (and vice versa). Additionally, there would be an SCR running from the 555 tigger pin that when fired would hold the 555 output low. The tigger of the SCR would be based on an RC combo that reaches the SCR tigger voltage after 1 second. If the R was a trim pot, one could adjust the time it was flashing before solid. When brake level released, it would unfire the SCR, allow the 555 to flash next application, but the discharge of the RC would prevent full flashes after each closely spaced brake application.

However, all I know is this high level arrangement and don't know how to actually diagram this out successfully. The hope is that is is a one wire in, one wire out splice, but I know there might need ot be a ground wire too.

dnurdy wrote:

Riding around chicago, I've become very interested in installing a brake light flasher after seeing the one's on the Chicago Police cars here. Very cool. When brakes applied, it does about 3 flashes in 1 second and the holds steady . .

The idea I had was this:

Drive really fast. Get pulled over. When they pull you over, start talking to them in electro lingo. They will think maybe something is amiss, and may put you in the back of the squad car for safekeeping.

While in the back of the police cruiser with the brake lights you admire, crawl under the seat to both the trunk and the underdash wiring areas, looking for clues as to how Chicago's finest get such nifty lights to operate.

Chances are, you will see some sort of interface box, right next to their radios and computers.

With a manufacturer's name on it.

Don't steal that box. That's a crime. You could go to jail for that.

After all, you are already half-way there, since you are either under the dash, or in the trunk, attempting to escape partial custody.

Emerging with a switch box from a police car is probably not a good idea.

Instead, scribble down the name of the manufacturer, and contact them. Maybe you could buy one, already tested, operational, with installation directions.

And not risk frying the electrical system on your bike in the process.

Or, better idea. Go to the City service garage, and ask the mechanics who install the boxes where they get them.

nice, but it takes the fun out of the long way around...

Didn't think of it in that sort of way. I just thought that after 9 pages of posts regarding your charging challenges, you might want to enjoy riding for awhile, rather than watching your work vaporize accidentally.

Especially since the bike starts without you having to push it all the time now.

Very true, but fiddling is fun.

The product exists already, it's the Kisan TailBailzer. I was just hoping to do the cheap DIY version.

But yes, you are right....winter will have time for such projects.

There are a million ways you could do this but for simplicity, you may want to consider using a 555/4017 combo. Here is a datasheet on the 4017.

It's simplistic and not the most elegant solution but it would do what you want and you could piece it together with one input, one output and ground and have it up and running within a few minutes. Think of it as a sequential with the final grounded via a relay.


Alternately, you could use two cascaded 555 outputs, one to drive the flashing and the other to drive the driver but that's a trip down half-assed, to say the least.




Now.......if you really want something cool. Do a fade pulse on your turn signals. Hell, your brakes too, why not?!

JCWhitney has a ready made flasher for 26 buckazoids in their catalogue, but I can't get their webpage to load to post a link. But, then I understand your wanting to DIY too. ,,
Ride safe

I already have a version of that timing circuit designed. I use it to flash the signals then automatically stop after 45 seconds. You could alter it to flash faster and quit after 1 second.

The core is a 556 dual-timer (two 555's in one package). I describe the parts associated in this write up.

www.geocities.com/loudgpz/GPZturnSigInteg.html

I think a simpler and better way would be to make a circuit that just fluctuates the brightness continuously while the brake is on. That circuit wouldn't be two hard to do either.

You have to do something to make the drunks notice you've stopped in front of them.

Post edited by: loudhvx, at: 2007/07/19 22:27

loudhvx wrote:

. . . You have to do something to make the drunks notice you've stopped in front of them.

How about, jumping off the bike, just before they rear-end you?

And planting your butt cheecks on their windshield when they miss the first signal?

the flashing 23 watt brake light

These work great. Put one on my old lady's bike. She had to have one of these and another to make her headlight flash on and off during the daytime. Really helps to stop people from pulling out in front of you. They think it's a cop coming down the road and so many people stop and tell her that the headlight is bilinking. It must be working. dnpurdy wrote:

Very true, but fiddling is fun.

The product exists already, it's the Kisan TailBailzer. I was just hoping to do the cheap DIY version.

But yes, you are right....winter will have time for such projects.

building it youself is neat, but when its already been done and it works, I dont want to reinvent the wheel,