Hi Everyone,

I am attempting to design a basic circuit that takes user input through buttons (H3 &H4) to have the motor spin in either direction using a L9110S Motor Driver. The part I am having trouble with is the implementation of a limiter. This motor spins a shaft that raises and lowers an object. The limiter in this case is are two ITR8307/TR8 on the top and bottom end. The issue arises where the limiter panel that the sensor sees is white while the rest of the time it sees black (This would be the inverse function of the photo-transistor. In-order to account for this, I believe I have setup a system where when the button is pressed and the sensors see black, the motor will spin in the respective direction, but when the sensor finally see white the power is shorted to ground stopping the motors from moving.

I believe my implementation of shorting the power directly to ground in this case is in-correct, but I am unsure of how to fix it. If anyone has suggestions I would be appreciative! Thanks!

 

If I have understood your requirement and circuit correctly, all that is necessary is to put a resistor (say, 10K) in the line between each HDR-F_2.54 and the 5V supply. Then when the ITR8307 sees white and conducts, the appropriate input will be pulled down to ground, but the current will be limited to a very small amount. As you have it at the moment, your ITR8307 transistors will be connected directly across the power supply and will probably have a lifetime of about 1mS!