Blinking yellow caution street sign circuit

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wachanna

Joined May 26, 2021
12
Hello electrophiles. Does anyone actually know what circuit and every component used to wire up a yellow blinking light used in street caution signs, or a educated guess? I would like to know, with pictures or a video of a step by step process, how to make that circuit. If you know of a good link to a step by step process to make the circuit, or an exact name of the circuit i could use to google to find info on how to make the circuit, god will see your kind act. Thanks.
 

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dl324

Joined Mar 30, 2015
13,506
It's just an oscillator with around a 50% duty cycle driving the two lights. Particulars regarding how to drive the "lights" depends on what the lights are (LEDs, incandescent), the available supply voltage, brightness requirements, etc. School lights will have some control for turning them on or off. Might be a timer with a clock, or a switch to turn them on manually.
 

Tonyr1084

Joined Sep 24, 2015
6,452
A single yellow blinking light can be easily achieved with just an automotive turn signal bulb (yellow), a blinker module and a 12 volt source. Double blinking lights are a little more complicated. They may use the same blinker module but need an additional relay to control a second light.

An electronic route would involve a 555 timer chip with some circuitry. You could still go with 12 volt turn signal bulbs OR you could go with LED's. I'm sure you can find plenty of 555 timer circuits on YouTube. Just check with us to make sure you happened on one that actually knows what he's doing. Lots of people on YouTube are there just to get clicks and a check.

As for designing a circuit - that's going to be your job. You know what you have and you know what you want. The rest of us are left to a guessing game.
 

crutschow

Joined Mar 14, 2008
28,158
A 555 timer configured as an astable multivibrator with a (near) 50% duty cycle controlling an N-MOSFET driving one of the lamps, with a second N-MOSFET gate controlled from the drain of the first, should work.
 

Ian0

Joined Aug 7, 2020
3,752
There are probably rules and regulations about what frequency with it should flash, and some jobsworth with a stopwatch. . .
 

Yaakov

Joined Jan 27, 2019
3,736
Hello electrophiles. Does anyone actually know what circuit and every component used to wire up a yellow blinking light used in street caution signs, or a educated guess? I would like to know, with pictures or a video of a step by step process, how to make that circuit. If you know of a good link to a step by step process to make the circuit, or an exact name of the circuit i could use to google to find info on how to make the circuit, god will see your kind act. Thanks.
That particular circuit will be a dedicated flashing beacon device with many functions. It the school zone case it is very likely an Eltec TC-18 or the equivalent. There is also the Eltec FS-2A for application where time schedules and crossing times are not important. Both these devices (particularly the TC-18) have a lot of functionality needed for actual traffic control devices.

If you don't need that, then one of the many options that other have mentioned will work.
 

Tonyr1084

Joined Sep 24, 2015
6,452
One place I worked - we had a truck horn used to signal break and quitting times. It was also used as a signaling device to warn occupants of the need to evacuate. To operate the warning someone had to push a button on a wall three times then exit. IF someone didn't hear the horn then they were at peril should the need to evacuate be legitimate.

Using a 12 volt transformer and bridge rectifier I rigged up a blinking light with one of those old style car blinker modules. It flashed the light. When the light flashed it also triggered a 12 volt relay. The normally open contacts were wired in parallel with the button so that when you turned on one switch a light would start flashing and the horn would start blowing. Continuously - until someone turned it off. That way - if you didn't hear the first three blasts, you eventually heard the horn because it was relentlessly warning of danger. Company policy was that, other than testing and fire drills, once triggered - ONLY the shop manager or fire marshal could turn it off.

It had its flaws though. If air pressure to blow the horn was not up to pressure then the horn would whimper and whine rather than blow. And if there was a power failure there would be no power to trigger the relay that triggered the horn.

Why are you building a caution street sign? If there's a need for such then it would be better if the city would put one in. Otherwise, if your home made device malfunctioned or caused confusion that resulted in harm or damage - guess who would be held responsible.
 

Dodgydave

Joined Jun 22, 2012
10,085
Hello electrophiles. Does anyone actually know what circuit and every component used to wire up a yellow blinking light used in street caution signs, or a educated guess? I would like to know, with pictures or a video of a step by step process, how to make that circuit. If you know of a good link to a step by step process to make the circuit, or an exact name of the circuit i could use to google to find info on how to make the circuit, god will see your kind act. Thanks.

Here's one using a 555 chip...

https://www.petervis.com/GCSE_Desig...-555-circuits/555-timer-dual-led-flasher.html
 

click_here

Joined Sep 22, 2020
446
I'm thinking more along the lines of a 2 transistor flasher circuit

[edit]
> "Does anyone actually know what circuit and every component used to wire up a yellow blinking light used in street caution signs"

Oh, you don't want to build your own, you want the "actual" circuit.

Or are you just wanting that circuit as a starting point?
[/edit]
 
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MisterBill2

Joined Jan 23, 2018
9,792
As described in post #7, the circuit used in the city placed signs is more complex and built to be mechanically much more durable than a hobby class circuit. And it may also need to control solar charging of the battery that runs the sign.
The circuit in one of those temporary construction flashers with the round yellow lens is the opposite. It is, or at leat used to be, a two transistor flip-flop with a photo-resistor to bias it to stop flashing during sunlight hours.About as simple a circuit as could be.
 
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