Ideals for tach data logging

Dakota99

Hi, I'm wanting to be a tach data logger for a sbc 350 w/hei that has a max reocrding time of 1:30 hrs if the sampling rate is 1/2 to 1 sec (this may vary, once i have a working prototype). My question is what parallax product to use for this? I have a bs2p24 (2 of them). I've seen how to get the tach signal off the hei throw the other postings. The Data logging has me stumped? So i'm open to any ideals. The small the better and of course cost is a factor. Power source is 12 volt, so low power consumtion is a plus(there not alternator on the car).