13.5 volts into a 555 timer ?

[fatfenders]

Wow, that sounds complicated. You could just use a 555 timer one shot to power the 555 flasher so that it only flashes for ten seconds (or twelve or whatever you want) so it doesn't matter if you leave the TS switch on since it stops flashing after the timed interval if you do. Next time you go to use it, you notice it's in the on (left or right) position and center it then use it as normal. Or the really simple solution I use: a 12V buzzer that beeps as the TS flashes to remind you to turn it off.

The solutions you suggest are just the situations I wanted to avoid. For me, A timed interval is unacceptable as it is too rigid. There are so many variables in terms of how long it may be desired to have the T/S on. By manually controlling the cancel function (again, by terminating an act I am currently performing) I have complete and precise control through an operation I am very unlikely to forget.
And I wouldn't even consider such an unelegant solution as the one you describe "Next time you go to use it, you notice it's in the on (left or right) position and center it then use it as normal."
And a buzzer is out of the question. Buzzers are usless in a high noise environment (a place motorcycles spent a good deal of time) where I am effectively wearing earplugs by way of a helmet.
All that said, I have to admit that I do like gadgets and this one is no exception!

 

[bountyhunter]

The solutions you suggest are just the situations I wanted to avoid. For me, A timed interval is unacceptable as it is too rigid. There are so many variables in terms of how long it may be desired to have the T/S on.

OK, for me I just need it on long enough to let the traffic behind me know I am turning.

And I wouldn't even consider such an unelegant solution as the one you describe "Next time you go to use it, you notice it's in the on (left or right) position and center it then use it as normal."

OK, since the thing turns off automatically, why would I care if the switch was not in the center? I guess I am not so hard to please.

And a buzzer is out of the question. Buzzers are usless in a high noise environment (a place motorcycles spent a good deal of time) where I am effectively wearing earplugs by way of a helmet.

Not the one I have. I have 58 year old ears damaged by a lifetime of playing drums in a band, playing music way to loud, and shooting competition pistols for the last 15 years and I hear the buzzer no problem even through the thickest padded helmet I could get. These buzzers are REALLY loud. Loud enough that I turn the turn signals off right after I make the turn because I don't want to hear it.

 

[fatfenders]

Bountyhunter,
I think you are a little confused… this thread is all about voltage input to a 555 board. Where you really want to be posting is on my thread with the subject “Please explain to me how all your ideas are better than all my ideas”. Of course, I have not posted it yet but when I do you will be one of the first to know.

 

[bountyhunter]

Bountyhunter,
I think you are a little confused… this thread is all about voltage input to a 555 board. .

I don't think I am confused. I covered that pretty concisely if you read my earlier post:

the IC will eventually die on a motorcycle unless some kind of series R and Zener protection is provided. I found that out the hard way, motorcycle electrics have a lot of transisents on the line. It killed my 555 flasher unit.

Don't know how to make it any clearer than that. Take it or leave it, your choice.

Please explain to me how all your ideas are better than all my ideas

I never claimed they were "better". Can't figure out how anybody would want to have to hold a button switch down to keep his turn signal flashing, your choice. As for:

(1)tap the left or right turn signal switch which applys that T/S for ,say, a maximum of 3 seconds.
(2)Within the time period, move my thumb down to the 'thumb' switch which keeps the T/S on until I release it
(3) Release the 'thumb' switch when I want to cancel.

You want to have your left thumb doing that when that hand is working the clutch? OK, your bike.

BTW, if you do make those mods you might want to keep a set of stock parts to restore it in case you ever have to pass registration check. The turn signals have to work as manufactured, at least in this state. Those mods would be illegal.

 

[fatfenders]

I just looked up that device you have. What is the full chip text and what voltage are the capacitors rated at?

Robert,
I did look up the chip (Fairchild KG37 LM555CN) and the voltage rating for the 2 Electrolytic Capacitors but forgot to report back... in fact this is one of the reasons I just decided to hook it up directly and see what happens. BTW, have been using the bike regularly and everything is still working fine).
Fairchild shows the chip to be rated for 16 volts, the 470μF capacitor is rated for 16v and the 1μF for 60 volts.

 

[fatfenders]

Its been exactly a month now since my last update on this thread so I decided to post this update to let those of you who where interested enough in this subject to post your thoughts, my results after running the 555 with no filtering for over a month. First, I replaced the faulty rectifier with a new O.E.M unit and now the voltage shows a very constant 14 volts at any RPM. I have used my scooter just about every day and the 'black box' continues to work flawlessly. It would seem to me that after a month of pretty continuous use that this is an indication that my 555 chip (rated for 16 volts) would have failed if it was going to fail.

 

[bountyhunter]

I use a 555 timer for the turn signal flasher on my bike. I do have zener clamp protection on mine, but some junk gets through. The 555 lasts a couple of years before it goes south. The one in there now is flaking out. I can tell when the flash rate starts to vary a little and is not consistent. I'll have to replace it soon.

 

[MrDEB]

would'nt it be cheaper?

install a better voltage regulator instead of replacing every few years?
a 555 = .50
an LDO regulator = under a $1
If one is building a project then design and build for worse case scenario. Not something that will crap out in a few months
Build crap you get crap, just don't complain why some purchased items don't work as planned due to bad design.

 

[fatfenders]

install a better voltage regulator instead of replacing every few years?
a 555 = .50
an LDO regulator = under a $1
If one is building a project then design and build for worse case scenario. Not something that will crap out in a few months
Build crap you get crap, just don't complain why some purchased items don't work as planned due to bad design.

"Build crap you get crap, just don't complain..."???

I began this thread by admitting I am just a 'hack' having some fun with some of my own ideas. What I built didn't cost much, has been fun to use, is non critical, is working fine and if/when it doesn't I can easily and cheaply go to the "B" model. In fact, right now, I am keen to determine, given all the dire predictions, just how long my 'black box' will hold up, as designed.
Its been my perception that forums such as this one are for the polite and supportive exchange of ideas and experiences. Here you refer to my effort as 'crap' and instruct me "not to complain" (as if I would in any case). I am always just a little disappointed when I see your kind of pejorative response to someone else's honest effort.

 

[MrDEB]

Sorry but I was referring to Bountyhunter

haveing to replace the 555 every few years or months??
sorry if you thought it was directed towards you.
When I design/build something be it out of wood or what ever medium I am working with, I get frustrated if it dosn't seem like it will last forever.
I have a habit of over engering just about everything I get involved with.
Sorry again if you felt my remark was directed towards you Fatfenders.

 

[bountyhunter]

Whatever.

A 555 timer is a part with maybe 18V breakdown rating. In an automotive system, that doesn't leave much headroom. I have protection on it, but sometimes stuff happens. It could be radiated high frequency noise from the CDI on my bike that puts very narrow (but high voltage) hash on the various power lines that act like antennas which degrades the part over time. Since it's only a turn signal flasher, the world doesn't come to an end if it acts up.

Whatever, it's on a socket and takes all of twenty seconds to change with a part I get for twenty five cents.

My post was a warning against the folly of putting any IC's on a bike that don't have some kind of protection, because they won't live very long. Bike/car makers have known this for many years and build it into all of their electronics.

 

[bountyhunter]

an LDO regulator = under a $1
If one is building a project then design and build for worse case scenario. Not something that will crap out in a few months

For the record, I spent about 20 years designing LDOs and their peripheral circuits. Even though a very few of them have specific protection against load dump (a specific kind of transient in an auto/bike electrical system) they are not immune to fast voltage transients and soetimes they get killed anyway. It's why designers often use zeners, tranzorbs, L-C filters and a host of other protection devices.

 

[Sceadwian]

Since it's only a turn signal flasher, the world doesn't come to an end if it acts up.

Until it fails when you're making a turn and a car turns 90% of your body into raw meat. In which case your world most definitly will come to an end.