Electronics > Beginners
Sequential tail lights
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robjodicarter:
So what should I order from either amazon or an electronic shop that will give me what I need. I know I need at least 2 bread boards( I'll buy a pack of 10) and. A 4017, a555 and I don't know what else? Sorry to be a pain but I really don't know what I'm doing. Should I try and buy one of those cheap diy kits to get ahold of what I'm trying to do and do some more research? Do you know where I could go to learn more about those chips or others? Thank you all.
I'll get back to you in the morning, it's 9. Pm here.
Rob

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Richard Crowley:

--- Quote from: james_s on September 23, 2018, 11:51:11 pm ---A 4017 only lights one LED at a time though,
--- End quote ---
No. The LM3915, 3916, and 3917 are all easily configurable for either "dot-mode" or "bar-mode" by simply connecting one of the pins.

And it is easy enough to use a single transistor on each output of the circuit (whichever circuit) to drive ("buffer") a very bright LED (or cluster of LEDs)


--- Quote --- The 4017 itself will tolerate 12V though and the LED brightness can be changed by changing the value of resistors used to limit the current. An automotive electrical system is notoriously dirty from an electrical standpoint though so I wouldn't expect that to last long without some modifications to bulletproof it.
--- End quote ---
Indeed. Most LED flasher circuits are not "ruggedized" for use in vehicle power systems.  It is easy enough to protect them, but the raw circuits you see online may have limited life expectancy in a vehicle.  And failure of a tail-light could get you killed.

IMHO those LM3915-16-17 chips aren't very appropriate for this design.  They depend on the rise-time of an analog signal and the method of generating that analog signal could be very vulnerable to things like supply voltage, temperature, etc. Perfectly fine for fooling around on the bench, but not nearly reliable enough for vehicular use. 

It would be far more reliable/bulletproof to use a series of the ubiquitous 555 (or the dual version, the 556) timer chips. There are many 3-step sequential tail light circuits using 555/556, but EXACTLY THE SAME scheme can be extended to 10 or ANY arbitrary number of steps.  And FAR MORE RELIABLE than an LM3915-16-17
BradC:

--- Quote from: tpowell1830 on September 24, 2018, 03:46:54 am ---Wow, really, your government forces you to buy parts from exclusive shops?
--- End quote ---

No. Like most other countries in the world there are regulations surrounding modifications on vehicles that must be complied with. Things like your average motoring dickhead replacing their halogen headlamps with LED or Xenon "replacements" and blinding any oncoming traffic are dealt with in the appropriate manner, by defecting the vehicle and forcing they go through a re-inspection process to ensure compliance. All other vehicle lights are similarly regulated. Not to say you can't modify, but you need to understand and comply with the rules.

There is a reason every single LED or Xenon drop-in replacement on the market is marked "for offroad use only" or "not ADR compliant".

There are no regulations about where you must buy your components, simply that they comply with the relevant regulations. Flashy LED tail-lights would fall under that category (non-compliant and likely to attract unwanted attention, or in the worst case at night triggering an epileptic".

Sorry, one of my big bugbears.

Actually the epilepsy factor is an interesting one. Years ago the Dubai Govt decided to cheap out on some solar powered illuminated cats eyes. Turns out they were flashing at just the right rate to trigger epileptics and resulted in several severe traffic accidents before they figured out what was going on and removed them.

tpowell1830:

--- Quote from: BradC on September 24, 2018, 04:32:29 am ---
--- Quote from: tpowell1830 on September 24, 2018, 03:46:54 am ---Wow, really, your government forces you to buy parts from exclusive shops?
--- End quote ---

No. Like most other countries in the world there are regulations surrounding modifications on vehicles that must be complied with. Things like your average motoring dickhead replacing their halogen headlamps with LED or Xenon "replacements" and blinding any oncoming traffic are dealt with in the appropriate manner, by defecting the vehicle and forcing they go through a re-inspection process to ensure compliance. All other vehicle lights are similarly regulated. Not to say you can't modify, but you need to understand and comply with the rules.

There is a reason every single LED or Xenon drop-in replacement on the market is marked "for offroad use only" or "not ADR compliant".

There are no regulations about where you must buy your components, simply that they comply with the relevant regulations. Flashy LED tail-lights would fall under that category (non-compliant and likely to attract unwanted attention, or in the worst case at night triggering an epileptic".

Sorry, one of my big bugbears.

Actually the epilepsy factor is an interesting one. Years ago the Dubai Govt decided to cheap out on some solar powered illuminated cats eyes. Turns out they were flashing at just the right rate to trigger epileptics and resulted in several severe traffic accidents before they figured out what was going on and removed them.

--- End quote ---

There are cars that come from the factory with Xenon and LED headlights, as well as flashy blinky sequential tail light turn signals. If you decided that you wanted them on your car, this wouldn't be allowed?
rjp:

--- Quote from: tpowell1830 on September 24, 2018, 05:01:18 am ---
--- Quote from: BradC on September 24, 2018, 04:32:29 am ---
--- Quote from: tpowell1830 on September 24, 2018, 03:46:54 am ---Wow, really, your government forces you to buy parts from exclusive shops?
--- End quote ---

No. Like most other countries in the world there are regulations surrounding modifications on vehicles that must be complied with. Things like your average motoring dickhead replacing their halogen headlamps with LED or Xenon "replacements" and blinding any oncoming traffic are dealt with in the appropriate manner, by defecting the vehicle and forcing they go through a re-inspection process to ensure compliance. All other vehicle lights are similarly regulated. Not to say you can't modify, but you need to understand and comply with the rules.

There is a reason every single LED or Xenon drop-in replacement on the market is marked "for offroad use only" or "not ADR compliant".

There are no regulations about where you must buy your components, simply that they comply with the relevant regulations. Flashy LED tail-lights would fall under that category (non-compliant and likely to attract unwanted attention, or in the worst case at night triggering an epileptic".

Sorry, one of my big bugbears.

Actually the epilepsy factor is an interesting one. Years ago the Dubai Govt decided to cheap out on some solar powered illuminated cats eyes. Turns out they were flashing at just the right rate to trigger epileptics and resulted in several severe traffic accidents before they figured out what was going on and removed them.

--- End quote ---

There are cars that come from the factory with Xenon and LED headlights, as well as flashy blinky sequential tail light turn signals. If you decided that you wanted them on your car, this wouldn't be allowed?

--- End quote ---

if they have the ADR acreditation you can, otherwise its the tedious game of getting them tested and approved.

i was perhaps a bit flippant in my previous post but the nutshell was wacking some led's and a flashing circuit on your taillights would get  police attention here and then its your job to prove your way out of it  - after your car has been taken off the road.

hence, going to a car shop and getting licensed gear and avoiding the tedium.

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