Basically what i'm trying to do is have two LDRs connected to a differential op-amp. The configuration has it high when LDR1 is low and LDR 2 is high with the rest of the combinations outputting low. Theres two op amps connected so that there are two distinct output channels so i have two high signals coming from the op-amps for both the low and high outcomes of the LDRs respectively, which represents the forward and reverse highs (for a motor). Now thats all well and good. But heres my problem. I want say for a high signal for forward, the motor to run for 5 seconds. So i've set up a monostable 555 timer circuit to do this. The problem being that the trigger of the 555 timer must be a momentary high, but the way my op-amps are they create a constant high. I don't know how to make it so that when I have a high signal for 'forward' from my op-amps the 555 timer to run just once and concurrently when i have a high signal for 'reverse' then the same thing (right now i'm using 2 555 timers, however thats if there is a simpler way to use one 555 timer to time both forward and reverse for my motor which uses a H bridge). Sorry if this sounds confusing. Ill try get a semi circuit up here if it is unclear. Thanks.