LED Project... Is the diagram correct?

[Maxer]

Okay i came up with this....
2 transistors. the flasher wire is the current wire used for indicator because it has pulse threw the bike flasher. and 12V be applied from seprated wire only hot when ignition is on. (gonna do that with a simple automotive relay... connect a current wire that is hot when ignition comes on to the electromagnet and make the connection from battery post the the circut on the other side of magnet) So this is what you were talking about right i am not sure about those resistors. Also if everything looks good can you identify all the values of the resistors and the POT and what type of transistors to use,
thanks
Max

 

[audioguru]

Hi Max,
Sorry for the delay. I have finally finished your circuit and simplified it, I didn't like your changes.
This one should work but may need the 470K resistor changed to match the speed of your flasher.

 

[Maxer]

Hi Max,
Sorry for the delay. I have finally finished your circuit and simplified it, I didn't like your changes.
This one should work but may need the 470K resistor changed to match the speed of your flasher.

HOw many mA to each led? would this work for only white leds running at like 3V or any leds this would work? what controls the sequence rate of the LED's should i just as a POT there so i can adjust accordingly?
Thanks for helping me out i really appreceiate this
max

 

[audioguru]

Hi Max,
The LED current is regulated at about 20mA each, and is determined by R1. That reminds me, you can get rid of R2 and ground pin 8.
You can use any kind of LEDs: red, blue, white , UV or even a mixture of colours.
The scan rate is determined by the 470K resistor and is about 1/2 second.
You can use a 1M linear pot in series with a 180K resistor instead of the 470K resistor if you want to adjust it from 380ms to 1.25 seconds.
This circuit will make all the LEDs off during the other half of the flasher's time.

 

[Maxer]

Hi Max,
The LED current is regulated at about 20mA each, and is determined by R1. That reminds me, you can get rid of R2 and ground pin 8.
You can use any kind of LEDs: red, blue, white , UV or even a mixture of colours.
The scan rate is determined by the 470K resistor and is about 1/2 second.
You can use a 1M linear pot in series with a 180K resistor instead of the 470K resistor if you want to adjust it from 380ms to 1.25 seconds.
This circuit will make all the LEDs off during the other half of the flasher's time.

so when flasher is on it will provide power to ckt & charge the cap
we can use a diode that will discharge that cap though that 470/1 W resistor when flasher is off
so what is the use of those transistors?
will the capacitor charge in log or linearly?
If in LOg i wont recognize the small delay right?
thanks
max

 

[audioguru]

Hi Max,
1) Yes, when flasher is on it will provide power to ckt & charge the cap.
2) The transistors are used to discharge the cap very quickly so that you don't see the LEDs "running the scan downward", since with the flasher turned off, the LM3914 is still powered by the 100uF cap for about 150ms.
3) The 1uF cap charges through the 470K resistor exponentially (starts charging quickly then slows down near full-charge), but since it charges to only about 63% of the supply voltage, it is fairly linear and the time for each LED during the scan will appear about the same.
4) There is a very short delay when the 1uF cap charges up to the threshold voltage for the 1st LED to turn on at about 1.3V when your battery is at 13.7V. The delay will be only about 50ms.