You could use a circuit commonly known as a window comparator, having adjustable thresholds. If you are going to build one with opamps, being that your lower threshold is so close to ground, I would consider comparators using a +/- supply voltage derived from the +12 single supply. Each threshold could be set with 10-turn pots acting as voltage dividers, or with digital pots and pushbuttons to adjust the threshold. You could use single supply "rail-to-rail" comparators too, but check the specs carefully due to that lower voltage threshold.