Hi everyone, I am new to electronics and I'm attempting to build a emergency vehicle type light. I have 2 555 flasher circuits built that work with an adjustable flash speed, my problem is alternating between the circuits. I originally thought just another 555 adj. flash speed circuit was the answer but I can't seem to get it to switch between them. any suggestions would be very appreciated. Sorry if I'm not posting correctly or if this has been covered, but I wasn't able to find anything in the search. Thanks in advance.

 

A third 555 will do the trick…you will need to connect the output directly to one of the 555s reset and connect to the other 555s reset through a transistor or inverter.

If you need a schematic let me know.

 

A schematic would be most appreciated. Thank you for your reply.

 

Schematic for flashing police lights

Wendy's Index

LED Police lights on a R/C truck

Police lightbar

 

Here ya go, what’s at the top is what you need, the rest is up to you…values etc…

The transistor inverts the first 555s output.

 

Can't you just change the frequency of the single 555 timer?

 

I have done this a lot, try searching "Wendy" as the user and "police" inn the AAC Search bar for different forums (BTW My name used to be Bill_Marsden). You can tag me to read a post by adding @Wendy in your post, this works for all users.

P.S. I love mentoring people.

 

Thanks to everyone that commented, it was a big help!! Lights look great on my RC firetruck.

 

Just curious, what did you finally go with?

 

I have 3 555 flash circuits 1 being timed to alternate between the other 2 and the other 2 for the higher flash speed of the lights. I have a 2n3904 npn to switch between the 2 flasher circuits. I will post my schematic when I finish it.