DIY encoders for tamiya dual gearbox

Hi, Want to add encoders to my tamiya dual gearbox, since i'm using bulky opto switches, i have easy access to a gear that rotates 7 times per revolution of the wheel, i thought of making 4 holes on that gear(in a north, south, east, west orientation), reckon 28 pulses per rotation will be enough? i basically just want them to make the robot drive in a straight line, though after it's all nice and functional i want to MAYBE add some mapping to it, is 28 enough, or should i try harder to make it fit in the gear that rotates 24times per wheel revolution(with 4 holes, that's 96 pulses per rotation) ?


so i either have:

28 pulse resolution(per wheel rotation) easy to make.


96 pulse resolution(per wheel rotation) but will be harder to make.


thanks :)

looks feasable

I’m liking these:


the tamiya gearbox is quite compact, though if that is as small as it looks, it should fit :slight_smile: