I want to make my 20 year old car do a Tach needle sweep you see in new cars. I have made a Freq generator that outputs exactly 8k rpms.
I just need to have a relay switch this feed with key on, but I am struggling with how to have it go off in just a few seconds to go back to normal operation.
Wasn't sure if a typical R/C circuit would dissipate evenly or quickly.
Goal is to turn car to Ing-'on', tach then sweeps from 0 rpms to 8,000 rpms then back to '0'. I have not physically timed this, but I am guessing 2 seconds it takes to go from 0-8,000-0. I can time it and adjust accordingly. So the time needed is really to get it to the 8000rpm mark, then the power can be removed so it can drop back down to 0 rpms
Any recommendations of what to use would be very helpful. I have started a simple schematic attached.
Stu
I just need to have a relay switch this feed with key on, but I am struggling with how to have it go off in just a few seconds to go back to normal operation.
Wasn't sure if a typical R/C circuit would dissipate evenly or quickly.
Goal is to turn car to Ing-'on', tach then sweeps from 0 rpms to 8,000 rpms then back to '0'. I have not physically timed this, but I am guessing 2 seconds it takes to go from 0-8,000-0. I can time it and adjust accordingly. So the time needed is really to get it to the 8000rpm mark, then the power can be removed so it can drop back down to 0 rpms
Any recommendations of what to use would be very helpful. I have started a simple schematic attached.
Stu