Developing Co2 sensor and regulator

Hi all,

I am developing a CO2 sensor and regulator for an incubator. I am linking a schematic of my design and hoping if I can get some feedback if there are any potential dangers.

Basically, the LED represents the sensor which can only handle between 6v to 12v. The two motors represents my regulator (solenoid) and a pump which share the same voltage source.

I want to know if this design is safe enough for my sensor where the voltage source for my two motors won't damage my sensor.

One last thing, when the arduino starts up it seems to put power into all of its pins which will send a start signal to all 3 transistors. Will this cause any damage? Right now only one motor is on at any time. Would sending a signal to close all three transistors at the same time cause damage?

Thanks,
Danh

I moved my thread to: