LCD or LED rev counter(tacho) info needed

[smokie]

Hi I m a newbie to electronics and Im looking for a schematic for an LCD tacho that will register 12000rpm.....or one for a LED tacho that will light a different LED as rpm increases....Im looking to use 15 LED's to represent one for every 500 rpm.....Can anyone help with this as Ive looked almost everywhere to find one.
Many thanx Ken

 

[gunny]

after reading your post it your idea to me like something ive built before i dont have the schemtic but i can give a chip # to help you along...maxim icm7224 or icm7225 if you wanna use led or led non multiplexed ..if you want multiplexed let me know and ill dig through a couple data books..as for your led bar the lm3914 would be a good start..both chips are cascadable for any resolution desired....ive built a couple using icl7107 and 6 using a freq to voltage converter also and were pretty accurate but didnt use 1% componets so they had some lineararity issues by as much as 50 - 60 rpm in cases in either low end or high end ..oh well should of forked out for the good stuff......hope this helps