Hello! I am new to the forums so greetings and thank you for reading this and any help you can provide!

So, I am trying to build a pulse generator to send half second, ~6V pulses to a small fan that blows into windchimes, creating a pleasant chime every so often.

I would like to make it variable by potentiometer to blow at minimum once every 30 seconds and at most around once every 5 minutes. I have been looking into using a 555 in monostable mode, but all my calculations end up with me having a R1 value of around negative 50k ohms. I am pretty new to this so bare with me.. Is it even possible for the 555 to oscillate at rates this low? Thank you for any help you can provide!!!

-William

 

I haven't used a 555 for years but I would think that this is possible using a CMOS 555.

 

Yes you can use 555 to generate such time periods but it won't be tht accurate.

Try to build one and use a LED to monitor the ouput. You are gonna need a fairly large capacitor to time 5 minutes

 

google "555 cmos timer 30 minute".

 

R-C time, 1 meg & 200 uF, discharge , pin 6 to pin 7, 150 K. Fan VCC to pin 3.

 

That takes care of the 5 minutes.

What are you planning for an output relay or 1/2sec delay off?