I would combine R1 and R2 into one (because they act as one resistor anyway). I guess R3 and R4 are the DIY sensors, are they? In this case it might work, but you should use PNP transistors if connected this way.
I would combine R1 and R2 into one (because they act as one resistor anyway). I guess R3 and R4 are the DIY sensors, are they? In this case it might work, but you should use PNP transistors if connected this way.